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Phenotype Correlations (phenotype + correlation)
Selected AbstractsSequestosome 1 Mutations in Paget's Disease of Bone in Australia: Prevalence, Genotype/Phenotype Correlation, and a Novel Non-UBA Domain Mutation (P364S) Associated With Increased NF-,B Signaling Without Loss of Ubiquitin Binding,,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 7 2009Sarah L Rea Abstract Previously reported Sequestosome 1(SQSTM1)/p62 gene mutations associated with Paget's disease of bone (PDB) cluster in, or cause deletion of, the ubiquitin-associated (UBA) domain. The aims of this study were to examine the prevalence of SQSTM1 mutations in Australian patients, genotype/phenotype correlations and the functional consequences of a novel point mutation (P364S) located upstream of the UBA. Mutation screening of the SQSTM1 gene was conducted on 49 kindreds with PDB. In addition, 194 subjects with apparently sporadic PDB were screened for the common P392L mutation by restriction enzyme digestion. HEK293 cells stably expressing RANK were co-transfected with expression plasmids for SQSTM1 (wildtype or mutant) or empty vector and a NF-,B luciferase reporter gene. GST-SQSTM1 (wildtype and mutant) proteins were used in pull-down assays to compare monoubiquitin-binding ability. We identified SQSTM1 mutations in 12 of 49 families screened (24.5%), comprising 9 families with the P392L mutation and 1 family each with the following mutations: K378X, 390X, and a novel P364S mutation in exon 7, upstream of the UBA. The P392L mutation was found in 9 of 194 (4.6%) patients with sporadic disease. Subjects with SQSTM1 mutations had more extensive disease, but not earlier onset, compared with subjects without mutations. In functional studies, the P364S mutation increased NF-,B activation compared with wildtype SQSTM1 but did not reduce ubiquitin binding. This suggests that increased NF-,B signaling, but not the impairment of ubiquitin binding, may be essential in the pathogenesis of PDB associated with SQSTM1 mutations. [source] Precocious puberty in Turner syndromeJOURNAL OF PAEDIATRICS AND CHILD HEALTH, Issue 11 2007Matthew A Sabin Abstract: Turner syndrome (TS) affects approximately 1 in 2000 liveborn girls. It is a common cause of short stature and is often, but not universally, associated with characteristic dysmorphic features and ovarian dysgenesis. Genotype/phenotype correlation in TS is generally poor and girls with TS may occasionally have normal functioning ovarian tissue, with approximately 30,40% entering puberty, 4% achieving menarche and 1% being fertile. In this report, we describe a girl with mosaic TS who unusually experienced spontaneous precocious puberty with associated accelerated longitudinal growth during mid childhood. This case acts as a useful clinical vignette with which to highlight important aspects of diagnosis and treatment in children with TS, particularly in relation to future growth potential and issues relating to fertility. [source] Novel UBA Domain Mutations of SQSTM1 in Paget's Disease of Bone: Genotype Phenotype Correlation, Functional Analysis, and Structural ConsequencesJOURNAL OF BONE AND MINERAL RESEARCH, Issue 7 2004Lynne J Hocking Abstract Three novel missense mutations of SQSTM1 were identified in familial PDB, all affecting the UBA domain. Functional and structural analysis showed that disease severity was related to the type of mutation but was unrelated to the polyubiquitin-binding properties of the mutant UBA domain peptides. Introduction: Mutations affecting the ubiquitin-associated (UBA) domain of Sequestosome 1 (SQSTM1) gene have recently been identified as a common cause of familial Paget's disease of bone (PDB), but the mechanisms responsible are unclear. We identified three novel SQSTM1 mutations in PDB, conducted functional and structural analyses of all PDB-causing mutations, and studied the relationship between genotype and phenotype. Materials and Methods: Mutation screening of the SQSTM1 gene was conducted in 70 kindreds with familial PDB. We characterized the effect of the mutations on structure of the UBA domain by protein NMR, studied the effects of the mutant UBA domains on ubiquitin binding, and looked at genotype-phenotype correlations. Results and Conclusions: Three novel missense mutations affecting the SQSTM1 UBA domain were identified, including a missense mutation at codon 411 (G411S), a missense mutation at codon 404 (M404V), and a missense mutation at codon 425 (G425R). We also identified a deletion leading to a premature stop codon at 394 (L394X). None of the mutations were found in controls. Structural analysis showed that M404V and G425R involved residues on the hydrophobic surface patch implicated in ubiquitin binding, and consistent with this, the G425R and M404V mutants abolished the ability of mutant UBA domains to bind polyubiquitin chains. In contrast, the G411S and P392L mutants bound polyubiquitin chains normally. Genotype-phenotype analysis showed that patients with truncating mutations had more extensive PDB than those with missense mutations (bones involved = 6.05 ± 2.71 versus 3.45 ± 2.46; p < 0.0001). This work confirms the importance of UBA domain mutations of SQSTM1 as a cause of PDB but shows that there is no correlation between the ubiquitin-binding properties of the different mutant UBA domains and disease occurrence or extent. This indicates that the mechanism of action most probably involves an interaction between SQSTM1 and a hitherto unidentified protein that modulates bone turnover. [source] Somatic NF1 mutation spectra in a family with neurofibromatosis type 1: Toward a theory of genetic modifiers,HUMAN MUTATION, Issue 6 2003Verena Wiest Abstract Neurofibromatosis type 1 (NF1), an autosomal dominantly-inherited disorder, is mainly characterized by the occurrence of multiple dermal neurofibromas and is caused by mutations in the NF1 gene, a tumor suppressor gene. The variable expressivity of the disease and the lack of a genotype/phenotype correlation prevents any prediction of patient outcome and points to the action of genetic factors in addition to stochastic factors modifying the severity of the disease. The analysis of somatic NF1 gene mutations in neurofibromas from NF1 patients revealed that each neurofibroma results from an individual second hit mutation, indicating that factors that influence somatic mutation rates may be regarded as potential modifiers of NF1. A mutational screen of numerous neurofibromas from two NF1 patients presented here revealed a predominance of point mutations, small deletions, and insertions as second hit mutations in both patients. Seven novel mutations are reported. Together with the results of studies that showed LOH as the predominant second hit in neurofibromas of other patients, our results suggest that in different patients different factors may influence the somatic mutation rate and thereby the severity of the disease. Hum Mutat 22:423,427, 2003. © 2003 Wiley-Liss, Inc. [source] Epidermolysis bullosa simplex in Japanese and Korean patients: genetic studies in 19 casesBRITISH JOURNAL OF DERMATOLOGY, Issue 2 2006K. Yasukawa Summary Background, Epidermolysis bullosa simplex (EBS) comprises a group of hereditary bullous diseases characterized by intraepidermal blistering caused by mutations in either keratin gene, KRT5 or KRT14. Significant correlation between the position of mutations within these proteins and the clinical severity of EBS has been noted. A recent report showed EBS cases in Israel had unique genetic features compared with European or U.S.A. associated families, which suggests that the ethnic and geographical features of EBS patients may be different. Objectives, To assess the possibility that EBS may present with certain specific features in Japanese and Koreans and to identify additional EBS mutations for genotype/phenotype correlation. Methods, EBS was clinically diagnosed and confirmed by transmission electron microscopic examination of a skin biopsy. Mutation analysis of KRT5 and KRT14 was performed by direct sequencing in 17 Japanese and two Korean EBS patients. Results, We have identified six novel KRT5 missense mutations (V143D, D158V, V186M, Q191P, R352S, G517D). R352S is the first mutation in the 2A domain. Most of these novel mutations changed amino acids that were evolutionarily conserved. Eight including all five mutations in EBS-Dowling,Meara patients have been previously reported. We were unable to detect mutations in five sporadic EBS-Koebner patients. The proportion of mutations in KRT5 (11 of 14; 78%) is higher than that for KRT14 mutations (3 of 14; 21%) in these Japanese and Korean EBS patients. Conclusions, Japanese and Korean patients with EBS showed very similar phenotype and genotype correlations with patients from Western countries. Whether the higher proportion of KRT5 mutations is a definite characteristic of Japanese and Korean patients with EBS or not, requires further research into mutations in Japanese and Korean people. [source] Phenotype and genotype in females with POU3F4 mutationsCLINICAL GENETICS, Issue 6 2009S Marlin X-linked deafness is a rare cause of hereditary isolated hearing impairment estimated as at least 1% or 2% of the non-syndromic hearing loss. To date, four loci for DFN have been identified and only one gene, POU3F4 responsible for DFN3, has been cloned. In males, DFN3 is characterized by a progressive deafness associated with perilymphatic gusher at stapes surgery and with a characteristic inner ear malformation. The phenotype of eight independent females carrying POU3F4 anomalies is defined, and a late-onset hearing loss is found in three patients. Only one has an inner ear malformation. No genotype/phenotype correlation is identified. [source] ,-thalassaemia masked by , gene defects and a new polyadenylation site mutation on the ,2-globin geneEUROPEAN JOURNAL OF HAEMATOLOGY, Issue 4 2010Cornelis L. Harteveld Abstract We report three examples of chronic anaemia involving complex combinations of ,- and ,-globin gene defects. The first case had a potential Hb H disease caused by the classic SEA/RW deletions masked by Hb E [,26(B8)Glu,Lys] in the homozygous state. The second had an unusual Hb H disease caused by compound heterozygosity for two different ,2 polyadenylation site mutations masked by a ,-thalassaemia heterozygosity. The third had an intermediate ,-thalassaemia with considerable anaemia caused by an as yet unknown polyadenylation site (AATAAA>AATAAC) mutation in combination with a common RW deletion masked by a common Hb C [,6(A3)Glu,Lys] heterozygosity. Diagnostic methods, genotype/phenotype correlations and the chance of overlooking these combinations during risk assessment in a multiethnic society are discussed. [source] Multiple endocrine neoplasia type 2 RET protooncogene database: Repository of MEN2-associated RET sequence variation and reference for genotype/phenotype correlations,HUMAN MUTATION, Issue 4 2009Rebecca L. Margraf Abstract Multiple endocrine neoplasia type 2 (MEN2) is an inherited, autosomal-dominant disorder caused by deleterious mutations within the RET protooncogene. MEN2 RET mutations are mainly heterozygous, missense sequence changes found in RET exons 10, 11, and 13,16. Our group has developed the publicly available, searchable MEN2 RET database to aid in genotype/phenotype correlations, using Human Genome Variation Society recommendations for sequence variation nomenclature and database content. The MEN2 RET database catalogs all RET sequence variation relevant to the MEN2 syndromes, with associated clinical information. Each database entry lists a RET sequence variation's location within the RET gene, genotype, pathogenicity classification, MEN2 phenotype, first literature reference, and comments (which may contain information on other clinical features, complex genotypes, and additional literature references). The MEN2 phenotype definitions were derived from the International RET Mutation Consortium guidelines for classification of MEN2 disease phenotypes. Although nearly all of the 132 RET sequence variation entries initially cataloged in the database were from literature reports, novel sequence variation and updated phenotypic information for any existing database entry can be submitted electronically on the database website. The database website also contains links to selected MEN2 literature reviews, gene and protein information, and RET reference sequences. The MEN2 RET database (www.arup.utah.edu/database/MEN2/MEN2_welcome.php) will serve as a repository for MEN2-associated RET sequence variation and reference for RET genotype/MEN2 phenotype correlations. Hum Mutat 0,1,9, 2009. © 2009 Wiley-Liss, Inc. [source] Screening of 25 Italian patients with Niemann-Pick a reveals fourteen new mutations, one common and thirteen private, in SMPD1,,HUMAN MUTATION, Issue 1 2004V. Ricci Abstract Niemann-Pick disease (NPD) results from the deficiency of lysosomal acid sphingomyelinase (SMPD1). To date, out of more than 70-disease associated alleles only a few of them have a significant frequency in various ethnic groups. In contrast, the remainder of the mutations are rare or private. In this paper we report the molecular characterization of an Italian series consisting of twenty-five NPD patients with the severe neurodegenerative A phenotype. Mutation detection identified a total of nineteen different mutations, including 14 novel mutations and five previously reported lesions. The known p.P189fs and the novel p.T542fs were the most frequent mutations accounting for 34% and 18% of the alleles, respectively. Screening the alleles for the three common polymorphisms revealed the variant c.1516G>A (exon 6) and the repeat in exon 1, but not the variant c.965C>T (exon 2). In absence of frequent mutations, the prognostic value of genotyping is limited. However, new genotype/phenotype correlations were observed for this disorder that could in the future facilitate genetic counseling and guide selection of patients for therapy. © 2004 Wiley-Liss, Inc. [source] Sequestosome 1 Mutations in Paget's Disease of Bone in Australia: Prevalence, Genotype/Phenotype Correlation, and a Novel Non-UBA Domain Mutation (P364S) Associated With Increased NF-,B Signaling Without Loss of Ubiquitin Binding,,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 7 2009Sarah L Rea Abstract Previously reported Sequestosome 1(SQSTM1)/p62 gene mutations associated with Paget's disease of bone (PDB) cluster in, or cause deletion of, the ubiquitin-associated (UBA) domain. The aims of this study were to examine the prevalence of SQSTM1 mutations in Australian patients, genotype/phenotype correlations and the functional consequences of a novel point mutation (P364S) located upstream of the UBA. Mutation screening of the SQSTM1 gene was conducted on 49 kindreds with PDB. In addition, 194 subjects with apparently sporadic PDB were screened for the common P392L mutation by restriction enzyme digestion. HEK293 cells stably expressing RANK were co-transfected with expression plasmids for SQSTM1 (wildtype or mutant) or empty vector and a NF-,B luciferase reporter gene. GST-SQSTM1 (wildtype and mutant) proteins were used in pull-down assays to compare monoubiquitin-binding ability. We identified SQSTM1 mutations in 12 of 49 families screened (24.5%), comprising 9 families with the P392L mutation and 1 family each with the following mutations: K378X, 390X, and a novel P364S mutation in exon 7, upstream of the UBA. The P392L mutation was found in 9 of 194 (4.6%) patients with sporadic disease. Subjects with SQSTM1 mutations had more extensive disease, but not earlier onset, compared with subjects without mutations. In functional studies, the P364S mutation increased NF-,B activation compared with wildtype SQSTM1 but did not reduce ubiquitin binding. This suggests that increased NF-,B signaling, but not the impairment of ubiquitin binding, may be essential in the pathogenesis of PDB associated with SQSTM1 mutations. [source] MECP2 mutations in Serbian Rett syndrome patientsACTA NEUROLOGICA SCANDINAVICA, Issue 6 2007A. Djarmati Background,,, Rett syndrome is a severe neurodevelopmental X-linked dominant disorder affecting 1/15,000 girls worldwide. Eight years ago, the MECP2 gene was associated with the devastating clinical features observed in Rett syndrome patients. Objectives,,, To investigate the spectrum and the frequency of MECP2 mutations in Serbian Rett syndrome patients. Patients and methods,,, We screened the MECP2 coding region by conventional mutational screening (single-strand conformation polymorphism/sequencing) in 24 patients of Serbian origin and in their 41 unaffected family members. In search for gene dosage alterations in seemingly mutation-negative girls, we developed a new, specific quantitative PCR method. Results,,, Nineteen patients (79%) carried MECP2 mutations, five of which were novel (one nonsense mutation, one duplication and three deletions). Fourteen previously described disease-causing sequence changes and one polymorphism were also detected. Detailed case reports are given for the carriers of the novel mutations. Large MECP2 rearrangements cause Rett syndrome in a significant number of girls without ,classic' mutations in this gene. Therefore, we developed a specific quantitative PCR method, covering MECP2 exons 3 and 4, which previously has not been used for screening. No dosage alterations of the two exons were found in the four tested mutation-negative girls. Conclusions,,, This is the first genetic study of Rett syndrome in Serbian patients describing the MECP2 mutational and phenotypic spectrum in this population. Detailed clinical descriptions of this ethnically homogeneous patient population add to our knowledge of genotype/phenotype correlations in this severe condition. [source] Inverted duplications deletions: underdiagnosed rearrangements??CLINICAL GENETICS, Issue 6 2009O Zuffardi Molecular techniques led to the discovery that several chromosome rearrangements interpreted as terminal duplications were in fact inverted duplications contiguous to terminal deletions. Inv dup del rearrangements originate through a symmetric dicentric chromosome that, after asymmetric breakage, generates an inv dup del and a deleted chromosome. In recurrent inverted duplications the dicentric chromosome is formed at meiosis through non-allelic homologous recombination. In non-recurrent inv dup del cases, dicentric intermediates are formed by non-homologous end joining or intrastrand annealing. Some authors hypothesized that in these cases the dicentric may have been formed directly in the zygote. Healing of the broken dicentric chromosomes can occur not only in a telomerase-dependent way but also through telomere capture and circularization thus creating translocated or ring inv dup del chromosomes. In all the cases reported up to now, the duplicated region was always longer than the deleted one, but we can safely assume that there is another group of rearrangements where the deleted region is longer than the duplicated portion. In general, in these cases, the cytogeneticist will suspect the presence of a deletion and confirm it by FISH with a subtelomeric probe, but he/she will almost certainly miss the duplication. It is likely that the conventional analysis techniques used until now have led to a substantial underestimate of the frequency of inv dup del rearrangements and that the widespread use of array-CGH in routine analysis will allow a more realistic estimate. Obviously, the concomitant presence of deletion and duplication has important consequences in genotype/phenotype correlations. [source] DNA sequence analysis for structure/function and mutation studies in Becker muscular dystrophyCLINICAL GENETICS, Issue 1 2005SA Hamed We systematically screened the whole coding region of 18 male muscular dystrophy patients whose clinical, histological and laboratory findings suggest Becker muscular dystrophy (present but abnormal dystrophin). No systematic mutation study of a cohort of patients with dystrophin of normal quality but abnormal quantity has been published. The complete coding sequence of the dystrophin gene (11 kb) of each patient was subjected to an automated sequence analysis by using muscle biopsy RNA; 535 bp of the gene promoter and 5,UTR were likewise sequenced. We identified seven disease-causing mutations (40%). Six were novel, including missense, nonsense, small deletion and splice site mutations. Sixty percent (11/18) of patients with decreased quantities of normal molecular weight dystrophin showed no mutation, but most of them had a family history highly suggestive of X-linked inheritance, suggesting transcription or translational deleterious affection, i.e. outside what was screened. Quantitative multiplex fluorescence polymerase chain studies of mutation-negative patients showed normal levels of dystrophin mRNA. In three patients, there was some reduction of the transcript suggesting a deleterious undetected gene change resulted in the reduction of RNA levels. Our data address important structure/function and genotype/phenotype correlations and it suggests that dystrophin protein studies must be interpreted with caution in deletion-negative male muscular dystrophy patients. [source] Genotype,phenotype correlation in skin fragility-ectodermal dysplasia syndrome resulting from mutations in plakophilin 1EXPERIMENTAL DERMATOLOGY, Issue 2 2002T. Hamada Abstract: We report a 42-year-old Japanese man with an unusual autosomal recessive genodermatosis. The clinical features comprised normal skin at birth, loss of scalp hair at 3-months of age after a febrile illness, progressive nail dystrophy during infancy, palmoplantar keratoderma starting around the age of 18 years and trauma-induced skin fragility and blisters noted from the age of 20 years. Skin biopsy of rubbed non-lesional skin revealed widening of spaces between adjacent keratinocytes from the suprabasal layer upwards. Electron microscopy demonstrated a reduced number of hypoplastic desmosomes. Immunohistochemical labeling showed a reduction in intercellular staining for the desmosome component plakophilin 1. Mutation analysis revealed a homozygous intron 11 donor splice site mutation in the plakophilin 1 gene, 2021+1 G>A (GenBank no. Z34974). RT-PCR, using RNA extracted from the skin biopsy, provided evidence for residual low levels of the full-length wild-type transcript (,8%) as well as multiple other near full-length transcripts, one of which was in frame leading to deletion of 17 amino acids from the 9th arm-repeat unit of the plakophilin 1 tail domain. Thus, the molecular findings help explain the clinical features in the patient, who has a similar but milder phenotype to previously reported patients with skin fragility-ectodermal dysplasia syndrome associated with complete ablation of plakophilin 1 (OMIM 604536). This new ,mitis' phenotype provides further clinicopathological evidence for the role of plakophilin 1 in keratinocyte cell,cell adhesion and ectodermal development. [source] Somatic APC mosaicism: a frequent cause of familial adenomatous polyposis (FAP),HUMAN MUTATION, Issue 10 2007Stefan Aretz Abstract Somatic mutational mosaicism presents a challenge for both molecular and clinical diagnostics and may contribute to deviations from predicted genotype,phenotype correlations. During APC mutation screening in 1,248 unrelated patients with familial adenomatous polyposis (FAP), we identified 75 cases with an assumed or confirmed de novo mutation. Prescreening methods (protein truncation test [PTT], DHPLC) indicated the presence of somatic mosaicism in eight cases (11%). Sequencing of the corresponding fragments revealed very weak mutation signals, pointing to the presence of either nonsense or frameshift mutations at low level. All mutations were confirmed and quantified by SNaPshot analysis: in leukocyte DNA from the eight patients, the percentage of mosaicism varied between 5.5% and 77%, while the proportion of the mutation in DNA extracted from adenomas of the respective patient was consistently higher. The eight mutations identified as mosaic are localized within codons 216,1464 of the APC gene. According to the known genotype,phenotype correlation, patients with mutations in this region exhibit typical or severe FAP. However, six of the eight patients presented with an attenuated or atypical polyposis phenotype. Our data demonstrate that in a fraction of FAP patients the causative APC mutation may not be detected due to weak signals or somatic mosaicism that is restricted to tissues other than blood. SNaPshot analysis was proven to be an easy, rapid, and reliable method of confirming low-level mutations and evaluating the degree of mosaicism. Some of the deviations from the expected phenotype in FAP can be explained by the presence of somatic mosaicism. Hum Mutat 28(10), 985,992, 2007. © 2007 Wiley-Liss, Inc. [source] Argininosuccinate lyase deficiency: mutational spectrum in Italian patients and identification of a novel ASL pseudogene,HUMAN MUTATION, Issue 7 2007Eva Trevisson Abstract Argininosuccinic aciduria (ASAuria) is an inborn error of metabolism caused by mutations in the argininosuccinate lyase (ASL) gene, which leads to the accumulation of argininosuccinic acid (ASA) in body fluids and severe hyperammonemia. A severe neonatal form and a milder late-onset variant are described. We report a novel ASL pseudogene located in the centromeric region of chromosome 7, 14 novel mutations in the ASL gene, and a novel intronic polymorphism found in a cohort of Italian patients. Our approach relied exclusively on genomic DNA analysis. We found seven missense mutations, two nonsense, three small insertions/deletions, and two splicing mutations. Only two patients harbored previously described mutations, and among the novel variants only two were present in more than one kindred. The pathogenicity of the splicing mutations was demonstrated by a functional splicing assay that employed a hybrid minigene. We also performed molecular modeling using the reported three-dimensional structure of ASL to predict the functional consequences of the missense mutations. There was no genotype,phenotype correlation. Patients with neonatal onset display developmental delay and seizures despite adequate metabolic control. Moreover, hepatomegaly, fibrosis, and abnormal liver function tests are common complications in these patients, but not in patients with the late infancy form. We stress the importance of mutation analysis in patients with ASAuria, to confirm the clinical diagnosis, and to perform DNA-based prenatal diagnosis in future pregnancies of these families. Hum Mutat 28(7), 694,702, 2007. © 2007 Wiley-Liss, Inc. [source] ZFHX1B mutations in patients with Mowat-Wilson syndrome,HUMAN MUTATION, Issue 4 2007Florence Dastot-Le Moal Abstract Mowat-Wilson syndrome (MWS) is a recently delineated mental retardation (MR)-multiple congenital anomaly syndrome, characterized by typical facies, severe MR, epilepsy, and variable congenital malformations, including Hirschsprung disease (HSCR), genital anomalies, congenital heart disease (CHD), and agenesis of the corpus callosum (ACC). It is caused by de novo heterozygous mutations or deletions of the ZFHX1B gene located at 2q22. ZFHX1B encodes Smad-interacting protein-1 (SMADIP1 or SIP1), a transcriptional corepressor involved in the transforming growth factor-, signaling pathway. It is a highly evolutionarily conserved gene, widely expressed in embryological development. Over 100 mutations have been described in patients with clinically typical MWS, who almost always have whole gene deletions or truncating mutations (nonsense or frameshift) of ZFHX1B, suggesting that haploinsufficiency is the basis of MWS pathology. No obvious genotype,phenotype correlation could be identified so far, but atypical phenotypes have been reported with missense or splice mutations in the ZFHX1B gene. In this work we describe 40 novel mutations and we summarize the various mutational reports published since the identification of the causative gene. Hum Mutat 28(4), 313,321, 2007. © 2007 Wiley-Liss, Inc. [source] Schimke immunoosseous dysplasia: suggestions of genetic diversity,,HUMAN MUTATION, Issue 3 2007J. Marietta Clewing Abstract Schimke immunoosseous dysplasia (SIOD), which is characterized by prominent spondyloepiphyseal dysplasia, T-cell deficiency, and focal segmental glomerulosclerosis, is a panethnic autosomal recessive multisystem disorder with variable expressivity. Biallelic mutations in switch/sucrose nonfermenting (swi/snf) &!ndash;related, matrix-associated, actin-dependent regulator of chromatin, subfamily a-like 1 (SMARCAL1) are the only identified cause of SIOD. However, among 72 patients from different families, we identified only 38 patients with biallelic mutations in the coding exons and splice junctions of the SMARCAL1 gene. This observation, the variable expressivity, and poor genotype,phenotype correlation led us to test several hypotheses including modifying haplotypes, oligogenic inheritance, or locus heterogeneity in SIOD. Haplotypes associated with the two more common mutations, R820H and E848X, did not correlate with phenotype. Also, contrary to monoallelic SMARCAL1 coding mutations indicating oligogenic inheritance, we found that all these patients did not express RNA and/or protein from the other allele and thus have biallelic SMARCAL1 mutations. We hypothesize therefore that the variable expressivity among patients with biallelic SMARCAL1 mutations arises from environmental, genetic, or epigenetic modifiers. Among patients without detectable SMARCAL1 coding mutations, our analyses of cell lines from four of these patients showed that they expressed normal levels of SMARCAL1 mRNA and protein. This is the first evidence for nonallelic heterogeneity in SIOD. From analysis of the postmortem histopathology from two patients and the clinical data from most patients, we propose the existence of endophenotypes of SIOD. Hum Mutat 28(3), 273,283, 2007. Published 2006, Wiley-Liss, Inc. [source] Mutational spectrum and genotype,phenotype correlations in mevalonate kinase deficiency,HUMAN MUTATION, Issue 8 2006Saskia H.L. Mandey Abstract Mevalonate kinase deficiency (MKD) is an autosomal recessive autoinflammatory disorder caused by mutations in the MVK gene resulting in deficient activity of mevalonate kinase (MK). Depending on the clinical severity, MKD may present as hyper-IgD and periodic fever syndrome (HIDS) or the more severe mevalonic aciduria (MA). We analyzed the MVK gene in 57 patients with MKD and found 39 different mutations including 15 novel mutations, expanding the total mutational spectrum of MKD to 63 mutations. To get more insight into the genotype,phenotype correlation in MKD, we studied the effect of selected missense mutations on MK protein stability and activity in various patient fibroblast cell lines. All MKD cell lines showed markedly decreased MK activities that correlated well with the clinical severity and, for most of the cell lines, with the amount of MK protein. When fibroblasts of MKD patients were cultured under conditions known to promote a more controlled protein folding, all cell lines of patients with the HIDS phenotype and few cell lines of patients with the MA phenotype showed an increase in the residual MK activity. This increase in enzyme activity correlates well with an increase in the MK protein levels in these cell lines, indicating that most of the mutations in MKD affect stability and/or folding of the MK protein rather than affecting the catalytic properties of the enzyme. The finding that the residual activity in MKD can be manipulated by environmental conditions may offer therapeutic options to alleviate or prevent the clinical symptoms associated with MKD. Hum Mutat 27(8), 796,802, 2006. © 2006 Wiley-Liss, Inc. [source] Genotype,phenotype correlation in von Hippel-Lindau families with renal lesionsHUMAN MUTATION, Issue 5 2004Catherine Gallou The original article to which this Erratum refers was published in Human Mutation 24:215,224 Human Mutation(2004) 24(3) 215,224 In the published version of this article, the key to Figure 2 was omitted. Please find Figure 2 printed here in its entirety. [source] The Y chromosome and male fertility and infertility,INTERNATIONAL JOURNAL OF ANDROLOGY, Issue 2 2003Csilla Krausz Summary Since 1995, thanks to a large number of studies, Y chromosome microdeletion screening has become part of the routine diagnostic work-up of severe male factor infertility. Many initial contradictory issues such as variability in deletion frequency, markers to be tested, presence of deletions in ,fertile' men, and genotype,phenotype correlation has been resolved. Past and present unresolved issues are discussed in this review. [source] Behavioural phenotype in Börjeson-Forssman-Lehmann syndromeJOURNAL OF INTELLECTUAL DISABILITY RESEARCH, Issue 4 2009C. F. De Winter Abstract Background Börjeson-Forssman-Lehmann syndrome (BFLs) is an X-linked inherited disorder characterised by unusual facial features, abnormal fat distribution and intellectual disability. As many genetically determined disorders are characterised not only by physical features but also by specific behaviour, we studied whether a specific behavioural phenotype exists in BFLs. Methods We studied in detail the behaviour of four molecularly proven BFLs patients, and reviewed available literature on BFLs specifically for behavioural characteristics. Results Behaviour in persons with BFLs is in general friendly, but can be challenging with externalising and thrill-seeking features. Social skills are good. However, variation among patients is wide. Three patients from a single family showed expressed hypersexual behaviour. This was not present in other patients. Conclusion In BFLs a specific behavioural phenotype exists and in behaviour general is challenging besides a friendly habit. Within single families more problematic behaviour may occur. Further behavioural and molecular analysis of a larger group of patients is warranted to determine whether a genotype-behavioural phenotype correlation exists. [source] Genotype,phenotype correlation in some autosomal recessive hereditary spastic paraplegiasJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 2 2004F Manganelli Hereditary spastic paraplegias (HSPs) are a group of clinically and genetically inherited disorders. Spastic paraparesis (SP), the main clinical feature of all HSPs can occur in relative isolation in the "pure" form or in combination with other neurological deficits in "complicated" forms. Autosomal dominant, autosomal recessive (AR) and X-linked recessive inheritance pattern of HSPs have been reported. At present, among AR-HSPs, three genes, paraplegin (SPG7), spartin (SPG20 , Troyer syndrome) and maspardin (SPG21) have been identified and six genetic loci have been mapped (SPG5, SPG11, SPG14, SPG15, SPG24, SPG25). We have evaluated 11 patients belonging to six AR-HSP families genetically identified as SPG5, SPG7, SPG11 and SPG15. In all patients electromyography, nerve conduction velocity studies, visual (VEPs), somatosensory (SSEPs), brainstem auditory (BAEPs) and magnetic motor (MMEPs) evoked potentials were performed. All 4 SPG5 patients, affected by a pure form of SP, showed abnormalities of both MMEPs and SSEPs, and two of them also VEP alterations. In the two SPG7 patients with complicated SP, MMEP abnormalities only were discovered. Among the three SPG11 patients affected by SP, complicated by mental retardation and thin corpus callosum, electrophysiological studies revealed MMEP abnormalities and signs of motor neuropathy in one of them. Finally, in the SPG15 family, presenting with SP associated with mental retardation and neurosensorial deafness, MMEP and BAEP alterations were found. [source] Genetic counseling and "molecular" prenatal diagnosis of holoprosencephaly (HPE),AMERICAN JOURNAL OF MEDICAL GENETICS, Issue 1 2010Sandra Mercier Abstract Holoprosencephaly (HPE) is a structural anomaly of the developing brain in which the forebrain fails to divide into two separate hemispheres and ventricles. The poor prognosis in the most severe forms justifies the importance of genetic counseling in affected families. The genetic counseling requires a thorough clinical approach given the extreme variability of phenotype and etiology. The karyotype is an essential diagnostic tool. Since mutations in the four major genes (SHH, ZIC2, SIX3, and TGIF) have been identified in HPE patients, molecular study is performed routinely in nonsyndromic HPE. New molecular tools, such as array-CGH analysis, are now part of the diagnostic process. Prenatal diagnosis is based primarily on fetal imaging, but "molecular" prenatal diagnosis can be performed if a mutation has been previously identified in a proband. Interpretations of molecular diagnosis must be given with caution, given the lack of strict genotype,phenotype correlation, and should be offered in addition to fetal imaging, using ultrasound followed by fetal MRI. We report on our experience of 15 molecular prenatal diagnoses from chorionic villi or amniotic fluid sampling. In eight instances, we were able to reassure the parents after taking into account the absence of the mutation in the fetus, previously identified before in a parent and/or a proband. Fetal RMI was normal later in pregnancy, and no child had medical problems after birth. The mutation was found in the seven other cases: four children were born, either without brain malformation and asymptomatic, or had a less severe form than the index case. © 2010 Wiley-Liss, Inc. [source] Methylmalonic acidaemia leads to increased production of reactive oxygen species and induction of apoptosis through the mitochondrial/caspase pathway,THE JOURNAL OF PATHOLOGY, Issue 4 2007E Richard Abstract Methylmalonic acidaemia (MMA) is a heterogeneous group of rare genetic metabolic disorders caused by defects related to intracellular cobalamin (vitamin B12) metabolism. Increasing evidence has emerged suggesting that free radical generation is involved in the pathophysiology of neurodegenerative diseases, including some inborn errors of metabolism. We have previously identified in MMA patients several differentially expressed proteins involved in oxidative stress [mitochondrial superoxide dismutase (MnSOD) and mitochondrial glycerophosphate dehydrogenase (mGPDH)] and apoptosis by a proteomic approach. We have now extensively evaluated various parameters related to oxidative stress and apoptosis in cultured fibroblasts from a spectrum of patients with methylmalonic acidaemia. Fibroblasts from several MMA patients showed a significant increase in intracellular reactive oxygen species (ROS) content and in MnSOD expression level with respect to controls, suggesting a cellular response to intrinsic ROS stress. Moreover, we have demonstrated, using siRNA, that mGPDH is an important ROS generator in MMA patients. Cells from patients with MMA had a higher rate of apoptosis than those of controls and there was evidence that this process primarily involves the mitochondrial/caspase-dependent pathway. ROS level,phenotype correlation revealed that patients with severe neonatal cblB disorder had elevated intracellular ROS content. These findings support the possible role of oxidative stress in the pathophysiology of methylmalonic acidaemia. Copyright © 2007 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [source] BAC-based upgrading and physical integration of a genetic SNP map in Atlantic salmonANIMAL GENETICS, Issue 1 2010S. Lorenz Summary A better understanding of the genotype,phenotype correlation of Atlantic salmon is of key importance for a whole range of production, life history and conservation biology issues attached to this species. High-density linkage maps integrated with physical maps and covering the complete genome are needed to identify economically important genes and to study the genome architecture. Linkage maps of moderate density and a physical bacterial artificial chromosome (BAC) fingerprint map for the Atlantic salmon have already been generated. Here, we describe a strategy to combine the linkage mapping with the physical integration of newly identified single nucleotide polymorphisms (SNPs). We resequenced 284 BAC-ends by PCR in 14 individuals and detected 180 putative SNPs. After successful validation of 152 sequence variations, genotyping and genetic mapping were performed in eight salmon families comprising 376 individuals. Among these, 110 SNPs were positioned on a previously constructed linkage map containing SNPs derived from expressed sequence tag (EST) sequences. Tracing the SNP markers back to the BACs enabled the integration of the genetic and physical maps by assigning 73 BAC contigs to Atlantic salmon linkage groups. [source] Categorizing immunoflourescence mapping in epidermolysis bullosa with pyloric atresia: Use as a broad prognostic indicatorAUSTRALASIAN JOURNAL OF DERMATOLOGY, Issue 3 2010John W Frew ABSTRACT Epidermolysis bullosa with pyloric atresia is a form of junctional epidermolysis bullosa associated with gastrointestinal abnormalities, which may include pyloric atresia. Genotype phenotype correlation is poorly understood and prognosis is difficult, if not impossible, to predict. Immunoflourescence mapping is an ideal candidate for developing a broad prognostic indicator for epidermolysis bullosa with pyloric atresia without the need for genetic mutation analysis. However, the tool developed in this paper does have limitations due to the small number of cases available and the effects of deleterious mutations in highly conserved cysteine residues on the predicted length of survival. [source] Molecular basis of EEC (ectrodactyly, ectodermal dysplasia, clefting) syndrome: five new mutations in the DNA-binding domain of the TP63 gene and genotype,phenotype correlationBRITISH JOURNAL OF DERMATOLOGY, Issue 1 2010S.E. Clements Summary EEC (ectrodactyly, ectodermal dysplasia, clefting; OMIM 604292) syndrome is an autosomal dominant developmental disorder. Characteristic clinical features comprise abnormalities in several ectodermal structures including skin, hair, teeth, nails and sweat glands as well as orofacial clefting and limb defects. Pathogenic mutations in the TP63 transcription factor have been identified as the molecular basis of EEC syndrome and to date 34 mutations have been reported. The majority of mutations involve heterozygous missense mutations in the DNA-binding domain of TP63, a region critical for direct interactions with DNA target sequences. In this report, we present an overview of EEC syndrome, discuss the role of TP63 in embryonic development and skin homeostasis, and report five new TP63 gene mutations. We highlight the significant intra- and interfamilial phenotypic variability in affected individuals and outline the emerging paradigm for genotype,phenotype correlation in this inherited ectodermal dysplasia syndrome. [source] The molecular genetics of the genodermatoses: progress to date and future directionsBRITISH JOURNAL OF DERMATOLOGY, Issue 1 2003A.D. Irvine Summary The Human Genome Mapping Project and allied rapid advances in genetic technology over the past decade have facilitated accurate association of allelic variations in several genes with specific skin phenotypes. Currently the genetic bases of the majority of the more common genodermatoses have been elucidated. In scientific terms this work has been extraordinarily successful and has yielded many new biological insights. These advances, although exciting, have yet to be translated into direct benefit for patients with these diseases. Genetic counselling has been greatly aided by gene identification, by the better understanding of genotype,phenotype correlation and by the disclosure of unexpected genetic mechanisms in some families. Knowledge of the molecular basis of these disorders has also been vital in enabling DNA-based prenatal diagnosis in several conditions and DNA-based preimplantation diagnosis has been used in a selected few. While this successful period of gene mapping is now nearing completion, progress towards the next goal, that of developing therapeutic strategies based on the knowledge of these underlying genetic mechanisms, has proven frustratingly slow. Despite the ready access to the skin compared with solid internal organs, the challenges of cutaneous gene therapy are legion and many technical issues need to be surmounted to enable gene replacement or modification of gene expression to have a useful role in these disorders. In this article we make a comprehensive review of progress to date in gene identification, genotype,phenotype correlation, prenatal diagnosis and cutaneous gene therapy, and we examine future directions for research in this field. [source] An adult female patient with ring chromosome 21: behavioural phenotype and results of high-resolution molecular characterisationACTA NEUROPSYCHIATRICA, Issue 4 2010Willem M.A. Verhoeven Verhoeven WMA, Bon BV, Egger JIM, Hoischen A, Doelman JC. An adult female patient with ring chromosome 21: behavioural phenotype and results of high-resolution molecular characterisation. Objective: A female adult patient with mild to moderate mental retardation and minor dysmorphisms was referred for neuropsychiatric examination because of psychotic and autistic symptoms and impulsive behaviours. Methods: Standardized neuropsychiatric and neuropsychological assessment as well as detailed somatic and neurological examination was performed. For genetic analysis, karyotyping, whole genome array analysis, and high-resolution detailed analysis of chromosome 21 were carried through. Results: Karyotyping showed a de novo ring chromosome 21: 46,XX,der(21)r(21)(p11q22.3). High-resolution array analysis demonstrated a complex aberration consisting of an interstitial duplication in 21q21.1, an interstitial deletion in 21q22.2q22.3, an interstitial deletion in 21q22.3 and a terminal deletion of 21q22.3. Apart from mild dysmorphisms, visual and auditory impairments, and infertility, no somatic or neurological abnormalities were found. A formal psychiatric diagnosis could not be established. The behavioural problems and the supposed psychiatric symptoms could be related to her disharmonic social cognitive profile. The behaviour normalized after the patient returned to a stable and structured living environment. Conclusion: High-resolution micro-array analysis techniques are essential to substantiate the genotype,phenotype correlation in patients with r(21) and other genetic disorders. Moreover, the results of this study stress the importance of the recognition of alexithymia as a potential cause for behavioural problems and psychiatric symptoms in patients with mental retardation in general. [source] | |||||||||||||