Home About us Contact
|
Home About us Contact | ||
|
|
||
Mutation Analysis (mutation + analysis)
Selected AbstractsAssociation Study and Mutation Analysis of Adiponectin Shows Association of Variants in APM1 with Complex Obesity in WomenANNALS OF HUMAN GENETICS, Issue 5 2009Sigri Beckers Summary We performed an association study and mutation analysis of the adiponectin (APM1) gene to study its involvement in the development of obesity. We also studied the interaction with peroxisome proliferator-activated receptor , (PPAR,). 223 obese women and 87 healthy female control subjects were used for association analysis. Mutation analysis was done on 95 morbidly obese adults and 123 overweight and obese children and adolescents. We selected 6 haplotype tagging SNPs in APM1 and the Pro12Ala variant (rs1805192) in PPAR, to study the interaction. The G allele of rs2241766 was more common in controls (cases 10.8% vs. controls 18.4%, nominal p = 0.011; OR = 0.57, nominal p = 0.018). The rs2241766/rs3774261 haplotype was also associated with obesity (nominal p = 0.004). Only the latter association remained significant after controlling for the False Discovery Rate. Resequencing of exon 2, exon 3 and intron 2 in 95 individuals did not reveal any SNPs in high linkage disequilibrium with rs2241766. No interaction with the Pro12Ala variant in PPAR, was detected. Mutation analysis of APM1 did not identify mutations. In conclusion, we found an association of an APM1 haplotype with obesity and found that APM1 mutations are not a common cause of monogenic obesity in our cohort. [source] Genetics of type 2 diabetes mellitus: status and perspectivesDIABETES OBESITY & METABOLISM, Issue 2 2005Lars Hansen Throughout the last decade, molecular genetic studies of non-autoimmune diabetes mellitus have contributed significantly to our present understanding of this disease's complex aetiopathogenesis. Monogenic forms of diabetes (maturity-onset diabetes of the young, MODY) have been identified and classified into MODY1,6 according to the mutated genes that by being expressed in the pancreatic ,-cells confirm at the molecular level the clinical presentation of MODY as a predominantly insulin secretory deficient form of diabetes mellitus. Genomewide linkage studies of presumed polygenic type 2 diabetic populations indicate that loci on chromosomes 1q, 5q, 8p, 10q, 12q and 20q contain susceptibility genes. Yet, so far, the only susceptibility gene, calpain-10 (CAPN10), which has been identified using genomewide linkage studies, is located on chromosome 2q37. Mutation analyses of selected ,candidate' susceptibility genes in various populations have also identified the widespread Pro12Ala variant of the peroxisome proliferator-activated receptor-, and the common Glu23Lys variant of the ATP-sensitive potassium channel, Kir6.2 (KCNJ11). These variants may contribute significantly to the risk type 2 diabetes conferring insulin resistance of liver, muscle and fat (Pro12Ala) and a relative insulin secretory deficiency (Glu23Lys). It is likely that, in the near future, the recent more detailed knowledge of the human genome and insights into its haploblocks together with the developments of high-throughput and cheap genotyping will facilitate the discovery of many more type 2 diabetes gene variants in study materials, which are statistically powered and phenotypically well characterized. The results of these efforts are likely to be the platform for major progress in the development of personalized antidiabetic drugs with higher efficacy and few side effects. [source] Tumorigenic effect of transcription factor hAP-2, and the intricate link between hAP-2, activation and squelchingMOLECULAR CARCINOGENESIS, Issue 4 2002Yihong Yu Abstract Overexpression of human activator protein-2, (hAP-2,) is carcinogenic. Its aberrant regulation is the underlying tumorigenic event in the human teratocarcinoma cell line PA-1. In this cell line excess hAP-2, protein binds and sequesters coactivators, which interferes with the activity of other activators and with its own activity. The N-terminus of hAP-2,, which contains an activation domain, is critical in squelching and tumorigenicity. Mutation analyses of the N-terminus region showed that activation and squelching were intricately linked; nevertheless, squelching could occur in the absence of activity. Cells overexpressing squelching-proficient mutants grew efficiently on soft agar irrespective of their ability to activate transcription, which indicates that these cells are tumorigenic. Mutants that lacked both properties were nontumorigenic. These results suggest that squelching, but not activation, causes transformation and that the factors that are sequestered at this region are critical in tumorigenesis. © 2001 Wiley-Liss, Inc. [source] Preimplantation genetic diagnosis of Morquio diseasePRENATAL DIAGNOSIS, Issue 10 2008Wafa Qubbaj Abstract Objectives Morquio syndrome is an autosomal recessive disease and mutations in the N -acetylgalactosamine 6-sulfate sulfatase (GALNS) gene cause Morquio type A disease. Preimplantation genetic diagnosis (PGD), an early form of prenatal diagnosis for couples at risk of transmitting inherited diseases, was applied to prevent transmission of this disease. Methods A couple with three affected children, having homozygous W159C (p. Trp 159 Cys) mutation in GALNS gene, underwent in vitro fertilization (IVF) treatment and PGD. Mutation analyses from the embryos were performed following whole genome amplification of single blastomeres using multiple displacement amplification (MDA). Results Three embryos were diagnosed as normal and two were transferred on day 4. The cycle resulted in a pregnancy and a live birth of a carrier male infant. Genetic haplotyping analysis of the infant and the leftover MDA samples enabled us to determine which embryo was implanted. The discrepancy in results was explained by allele dropout (ADO) of the mutant allele from the MDA product. Conclusions A feasible strategy for PGD of Morquio disease including whole genome amplification by MDA and the use of preimplantation genetic haplotyping is described. MDA product archiving will be useful for future investigations if needed. Copyright © 2008 John Wiley & Sons, Ltd. [source] Epidemiological Approach to Identifying Genetic Predispositions for Atypical Hemolytic Uremic SyndromeANNALS OF HUMAN GENETICS, Issue 1 2010Maren Sullivan Summary Atypical hemolytic uremic syndrome (aHUS) is caused by several susceptibility genes. A registry including analyses of susceptibility genes, familial occurrence and genotype-phenotype correlation should provide classification insights. Registry data of 187 unrelated index patients included age at onset, gender, family history, relapse of aHUS and potentially triggering conditions. Mutation analyses were performed in the genes CFH, CD46 and CFI and in the six potential susceptibility genes, FHR1 to FHR5 and C4BP. Germline mutations were identified in 17% of the index cases; 12% in CFH, 3% in CD46 and 2% in CFI. Twenty-nine patients had heterozygous mutations and one each had a homozygous and compound heterozygous mutation. Mutations were not found in the genes FHR1-5 and C4BP. In 40% of the patients with familial HUS a mutation was found. Penetrance by age 45 was 50% among carriers of any mutation including results of relatives of mutation-positive index cases. The only risk factor for a mutation was family history of HUS (p = 0.02). Penetrance of aHUS in carriers of mutations is not complete. Occurrence of homo- and heterozygous mutations in the same gene suggests that the number of necessary DNA variants remains unclear. Among clinical information only familial occurrence predicts a mutation. [source] The occurrence of dominant spinocerebellar ataxias among 251 Finnish ataxia patients and the role of predisposing large normal alleles in a genetically isolated populationACTA NEUROLOGICA SCANDINAVICA, Issue 3 2005V. Juvonen Objectives,,, Frequency and distribution of dominant ataxias caused by dynamic mutations may vary in different populations, which has been explained on the basis of relative frequency of predisposing normal alleles. The aim of the study was to evaluate the occurrence of spinocerebellar ataxias (SCAs) and dentatorubral-pallidoluysian atrophy (DRPLA) in Finland, and to investigate the role of predisposing normal alleles in a genetically homogenous population. Material and methods,,, Mutation analyses for SCA1, 2, 3, 6, 7, 8, 10, 12, 17, and DRPLA and frataxin genes were performed for 251 unrelated Finnish patients who presented with progressive ataxia disorder. Results,,, Expansions of SCA1, SCA2, SCA6, SCA7, SCA8, and SCA17 genes were detected in 2, 1, 1, 7, 22, and 1 patients, respectively. Altogether, 39 and 7% of dominant and sporadic SCA patients, respectively, harboured expansions at some of the investigated loci. Normal variation, collected from 477 to 502 chromosomes at each disease loci, revealed that Finns were different from the Japanese but largely similar to other Caucasians. Conclusions,,, Lack of SCA3 and excess of SCA8 are characteristic to the Finnish population. Homozygosity for the SCA8 expansion increases penetrance. Frequencies of large normal alleles at the SCA loci predict poorly prevalence of the respective diseases in Finland. Prioritization in DNA testing, based on ethnic origin and geographical location, is recommendable in Finland, and analogous approach may be applied to other countries as well. [source] A severe form of Noonan syndrome and autosomal dominant café-au-lait spots , evidence for different genetic originsACTA PAEDIATRICA, Issue 4 2009Anna-Maja Nyström Abstract Aim: The clinical overlap among Noonan syndrome (NS), cardio-facio-cutaneous (CFC), LEOPARD and Costello syndromes as well as Neurofibromatosis type 1 is extensive, which complicates the process of diagnosis. Further genotype,phenotype correlations are required to facilitate future diagnosis of these patients. Therefore, investigations of the genetic cause of a severe phenotype in a patient with NS and the presence of multiple café-au-lait spots (CAL) spots in the patient and four members of the family were performed. Methods: Mutation analyses of candidate genes, PTPN11, NF1, SPRED1 and SPRED2, associated with these syndromes, were conducted using DNA sequencing. Results: A previously identified de novo mutation, PTPN11 F285L and an inherited NF1 R1809C substitution in the index patient were found. However, neither PTPN11 F285L, NF1 R1809C, SPRED1 nor SPRED2 segregated with CAL spots in the family. The results indicate that the familial CAL spots trait in this family is caused by a mutation in another gene, distinct from previous genes associated with CAL spots in these syndromes. Conclusion: We suggest that the atypical severe symptoms in the index patient may be caused by an additive effect on the F285L mutation in PTPN11 by another mutation, for example the NF1 R1809C or alternatively, the not yet identified gene mutation associated with CAL spots in this family. [source] Autosomal dominant nocturnal frontal lobe epilepsy with a mutation in the CHRNB2 geneEPILEPSIA, Issue 3 2008Fernando Díaz-Otero Summary Autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE; MIM 600513) has been associated with mutations in the genes coding for the alfa-4 (CHRNA4), beta-2 (CHRNB2), and alpha-2 (CHRNA2) subunits of the neuronal nicotinic acetylcholine receptor (nAChR) and for the corticotropin-releasing hormone (CRH). A four-generation ADNFLE family with six affected members was identified. All affected members presented the clinical characteristics of ADNFLE. Interictal awake and sleep EEG recordings showed no epileptiform abnormalities. Ictal video-EEG recordings showed focal seizures with frontal lobe semiology. Mutation analysis of the CHRNB2 gene revealed a c.859G>A transition (Val287Met) within the second transmembrane domain, identical to that previously described in a Scottish ADNFLE family. To our knowledge, this is the third family reported presenting a mutation in CHRNB2. The clinical phenotype appears similar to that described with mutations in CHRNA4, suggesting that mutations in these two subunits lead to similar functional alterations of the nAChR. [source] Neonatal isoimmune thrombocytopenia caused by type I CD36 deficiency having novel splicing isoforms of the CD36 geneEUROPEAN JOURNAL OF HAEMATOLOGY, Issue 1 2008Takeshi Taketani Abstract Neonatal alloimmune thrombocytopenia (NAIT) occurs because of transplacentally acquired maternal platelet alloantibodies. Most of the alloantibodies are against human platelet antigens, but the alloantibody against CD36 is rare. A full-term female baby was delivered by a mother who experienced two spontaneous abortions. The baby had thrombocytopenia with cephalhematoma. The platelet count increased by immunoglobulin therapy (400 mg/kg) for 3 d. Platelet antibody was detected in the postpartum maternal serum. The specificity of the antibody directed against platelets was identified as anti-Naka (CD36). Flow cytometric analysis showed no expression of CD36 in both platelets and monocytes from mother. Mutation analysis revealed two different splicing isoforms of maternal CD36 mRNA. One allele was exon 4 skipping, another was exon 9 skipping, both of which led to a frameshift and produced a truncated CD36 protein. These results indicate that NAIT is caused by maternal CD36 deficiency having CD36 splicing abnormalities. [source] Mutation analysis and characterization of COL7A1 mutations in dystrophic epidermolysis bullosaEXPERIMENTAL DERMATOLOGY, Issue 7 2008Ningning Dang Abstract:, Dystrophic epidermolysis bullosa (DEB) is inherited in both an autosomal dominant DEB and autosomal recessive manner RDEB, both of which result from mutations in the type VII collagen gene (COL7A1). To date, 324 pathogenic mutations have been detected within COL7A1 in different variants of DEB; many mutations are clustered in exon 73 (10.74%) which is close to the 39 amino acid interruption region. Dominant dystrophic epidermolysis bullosa usually involves glycine substitutions within the triple helix of COL7A1 although other missense mutations, deletions or splice-site mutations may underlie some cases. In recessive dystrophic epidermolysis bullosa, the mutations include nonsense, splice site, deletions or insertions, ,silent' glycine substitutions within the triple helix and non-glycine missense mutations within the triple helix or non-collagenous NC-2 domain. The nature of mutations in COL7A1 and their positions correlate reasonably logically with the severity of the resulting phenotypes. [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] Successful use of recombinant factor VIIa in a patient with inhibitor secondary to severe factor XI deficiencyHAEMOPHILIA, Issue 2 2002P. LAWLER Factor XI (FXI) inhibitors are a rare complication of inherited FXI deficiency. We report the successful use of recombinant factor VIIa (FVIIa) in a patient with a high-responding inhibitor undergoing cataract extraction. At the time of surgery there were limited available data on the optimal management of patients with FXI deficiency. A 62-year-old Ashkenazi Jewish woman had a lifelong history of excessive bleeding secondary to severe FXI deficiency (2 U dL,1), and received FXI concentrate (FXI:C) when she underwent a colposuspension procedure. She was subsequently diagnosed with a FXI inhibitor of 16 Bethesda units (BU) when she developed a poor response to FXI:C at the time of total hip replacement. Two months later she was admitted for cataract extraction. The FXI level was < 1 U dL,1 with an inhibitor titre of 48 BU. She received 90 ,g kg,1 of FVIIa immediately preoperatively followed by continuous infusion at a rate of 20 ,g kg,1 h,1 for 24 h. The cataract extraction was successful and there was no excess bleeding during surgery or in the postoperative period. Mutation analysis of the FXI gene showed that the patient was homozygous for the type II genotype [exon 5, Glu117,Ter]. The reason for the low prevalence of inhibitor formation in patients with FXI deficiency is unclear but may reflect a number of factors including reporting bias, the rarity of absent circulating FXI:C activity, and the infrequent use of FXI replacement therapy. [source] Mucopolysaccharidosis type IIID: 12 new patients and 15 novel mutations,HUMAN MUTATION, Issue 5 2010Marlies J. Valstar Abstract Mucopolysaccharidosis III D (Sanfilippo disease type D, MPS IIID) is a rare autosomal recessive lysosomal storage disorder previously described in only 20 patients. MPS IIID is caused by a deficiency of N-acetylglucosamine-6-sulphate sulphatase (GNS), one of the enzymes required for the degradation of heparan sulphate. So far only seven mutations in the GNS gene have been reported. The clinical phenotype of 12 new MPS IIID patients from 10 families was studied. Mutation analysis of GNS was performed in 16 patients (14 index cases). Clinical signs and symptoms of the MPS IIID patients appeared to be similar to previously described patients with MPS III. Early development was normal with onset of behavioral problems around the age of 4 years, followed by developmental stagnation, deterioration of verbal communication and subsequent deterioration of motor functions. Sequence analysis of the coding regions of the gene encoding GNS (GNS) resulted in the identification of 15 novel mutations: 3 missense mutations, 1 nonsense mutation, 4 splice site mutations, 3 frame shift mutations, 3 large deletions and 1 in-frame small deletion. They include the first missense mutations and a relatively high proportion of large rearrangements, which warrants the inclusion of quantitative techniques in routine mutation screening of the GNS gene. © 2010 Wiley-Liss, Inc. [source] Mutational spectrum of DMD mutations in dystrophinopathy patients: application of modern diagnostic techniques to a large cohort,HUMAN MUTATION, Issue 12 2009Kevin M. Flanigan Abstract Mutations in the DMD gene, encoding the dystrophin protein, are responsible for the dystrophinopathies Duchenne Muscular Dystrophy (DMD), Becker Muscular Dystrophy (BMD), and X-linked Dilated Cardiomyopathy (XLDC). Mutation analysis has traditionally been challenging, due to the large gene size (79 exons over 2.2,Mb of genomic DNA). We report a very large aggregate data set comprised of DMD mutations detected in samples from patients enrolled in the United Dystrophinopathy Project, a multicenter research consortium, and in referral samples submitted for mutation analysis with a diagnosis of dystrophinopathy. We report 1,111 mutations in the DMD gene, including 891 mutations with associated phenotypes. These results encompass 506 point mutations (including 294 nonsense mutations) and significantly expand the number of mutations associated with the dystrophinopathies, highlighting the utility of modern diagnostic techniques. Our data supports the uniform hypermutability of CGA>TGA mutations, establishes the frequency of polymorphic muscle (Dp427m) protein isoforms and reveals unique genomic haplotypes associated with "private" mutations. We note that 60% of these patients would be predicted to benefit from skipping of a single DMD exon using antisense oligonucleotide therapy, and 62% would be predicted to benefit from an inclusive multiexonskipping approach directed toward exons 45 through 55. Hum Mutat 30:1657,1666, 2009. © 2009 Wiley-Liss, Inc. [source] Genetic variability in the mitochondrial serine protease HTRA2 contributes to risk for Parkinson disease,HUMAN MUTATION, Issue 6 2008Veerle Bogaerts Abstract In one genetic study, the high temperature requirement A2 (HTRA2) mitochondrial protein has been associated with increased risk for sporadic Parkinson disease (PD). One missense mutation, p.Gly399Ser, in its C-terminal PDZ domain (from the initial letters of the postsynaptic density 95, PSD-95; discs large; and zonula occludens-1, ZO-1 proteins [Kennedy, 1995]) resulted in defective protease activation, and induced mitochondrial dysfunction when overexpressed in stably transfected cells. Here we examined the contribution of genetic variability in HTRA2 to PD risk in an extended series of 266 Belgian PD patients and 273 control individuals. Mutation analysis identified a novel p.Arg404Trp mutation within the PDZ domain predicted to freeze HTRA2 in an inactive form. Moreover, we identified six patient-specific variants in 5, and 3, regulatory regions that might affect HTRA2 expression as supported by data of luciferase reporter gene analyses. Our study confirms a role of the HTRA2 mitochondrial protein in PD susceptibility through mutations in its functional PDZ domain. In addition, it extends the HTRA2 mutation spectrum to functional variants possibly affecting transcriptional activity. The latter underpins a previously unrecognized role for altered HTRA2 expression as a risk factor relevant to parkinsonian neurodegeneration. Hum Mutat 29(6), 832,840, 2008. © 2008 Wiley-Liss, Inc. [source] Mutation analysis in nephronophthisis using a combined approach of homozygosity mapping, CEL I endonuclease cleavage, and direct sequencing,HUMAN MUTATION, Issue 3 2008Edgar A. Otto Abstract Nephronophthisis (NPHP), an autosomal recessive kidney disease, is the most frequent genetic cause of chronic renal failure in the first three decades of life. Mutations in eight genes (NPHP1,8) have been identified. We here describe a combined approach for mutation screening of NPHP1, NPHP2, NPHP3, NPHP4, and NPHP5 in a worldwide cohort of 470 unrelated patients with NPHP. First, homozygous NPHP1 deletions were detected in 97 patients (21%) by multiplex PCR. Second, 25 patients with infantile NPHP were screened for mutations in inversin (NPHP2/INVS). We detected a novel compound heterozygous frameshift mutation (p.[Q485fs]+[R687fs]), and a homozygous nonsense mutation (p.R899X). Third, 37 patients presenting with NPHP and retinitis pigmentosa (Senior-Løken syndrome [SLS]) were screened for NPHP5/IQCB1 mutations by direct sequencing. We discovered five different (three novel) homozygous premature termination codon (PTC) mutations (p.F142fsX; p.R461X; p.R489X; p.W444X; and c.488,1G>A). The remaining 366 patients were further investigated for mutations in NPHP1, NPHP3, and NPHP4. We applied a "homozygosity only" strategy and typed three highly polymorphic microsatellite markers at the respective loci. A total of 32, eight, and 14 patients showed homozygosity, and were screened by heteroduplex crude celery extract (CEL I) endonuclease digests. The sensitivity of CEL I was established as 92%, as it detected 73 out of 79 different known mutations simply on agarose gels. A total of 10 novel PTC mutations were found in NPHP1 (p.P186fs, p.R347X, p.V492fs, p.Y509X, and c.1884+1G>A), in NPHP3 (c.3812+2T>C and p.R1259X), and in NPHP4 (p.R59X, p.T1004fs, and p.V1091fs). The combined homozygosity mapping and CEL I endonuclease mutation analysis approach allowed us to identify rare mutations in a large cohort of patients at low cost. Hum Mutat 29(3), 418,426, 2008. © 2007 Wiley-Liss, Inc. [source] USH2A Mutation analysis in 70 Dutch families with Usher syndrome type II,,HUMAN MUTATION, Issue 2 2004Ronald J.E. Pennings Abstract Usher syndrome type II (USH2) is characterised by moderate to severe high-frequency hearing impairment, progressive visual loss due to retinitis pigmentosa and intact vestibular responses. Three loci are known for USH2, however, only the gene for USH2a (USH2A) has been identified. Mutation analysis of USH2A was performed in 70 Dutch USH2 families. Ten mutations in USH2A were detected, of which three are novel, c.949C>A, c.2242C>T (p.Gln748X) and c.4405C>T (p.Gln1468X). Including 9 previously published Dutch USH2a families, estimates of the prevalence of USH2a in the Dutch USH2 population were made. Mutations were identified in 62% of the families. In 28% both mutated alleles were identified, whereas in 34% the mutation in only one allele was found. It is estimated that about 28% of the Dutch USH2 families have a different causative gene. Analysis of deduced haplotypes suggests that c.1256G>T (p.Cys419Phe) is a Dutch ancestral mutation, occurring in 16% of the alleles. © 2004 Wiley-Liss, Inc. [source] Knobloch syndrome: Novel mutations in COL18A1, evidence for genetic heterogeneity, and a functionally impaired polymorphism in endostatin,HUMAN MUTATION, Issue 1 2004Olivier Menzel Abstract Knobloch syndrome (KNO) is an autosomal recessive disorder characterized by high myopia, vitreoretinal degeneration with retinal detachment, and congenital encephalocele. Pathogenic mutations in the COL18A1 gene on 21q22.3 were recently identified in KNO families. Analysis of two unrelated KNO families from Hungary and New Zealand allowed us to confirm the involvement of COL18A1 in the pathogenesis of KNO and to demonstrate the existence of genetic heterogeneity. Two COL18A1 mutations were identified in the Hungarian family: a 1-bp insertion causing a frameshift and a premature in-frame stop codon and an amino acid substitution. This missense variant is located in a conserved amino acid of endostatin, a cleavage product of the carboxy-terminal domain of collagen alpha 1 XVIII. D1437N (D104N in endostatin) likely represents a pathogenic mutation, as we show that the endostatin N104 mutant is impaired in its affinity towards laminin. Linkage to the COL18A1 locus was excluded in the New Zealand family, providing evidence for the existence of a second KNO locus. We named the second unmapped locus for Knobloch syndrome KNO2. Mutation analysis excluded COL15A1, a member of the multiplexin collagen subfamily similar to COL18A1, as being responsible for KNO2. Hum Mutat 23:77,84, 2004. © 2003 Wiley-Liss, Inc. [source] Mutation analysis in mitochondrial fatty acid oxidation defects: Exemplified by acyl-CoA dehydrogenase deficiencies, with special focus on genotype,phenotype relationshipHUMAN MUTATION, Issue 3 2001Niels Gregersen Abstract Mutation analysis of metabolic disorders, such as the fatty acid oxidation defects, offers an additional, and often superior, tool for specific diagnosis compared to traditional enzymatic assays. With the advancement of the structural part of the Human Genome Project and the creation of mutation databases, procedures for convenient and reliable genetic analyses are being developed. The most straightforward application of mutation analysis is to specific diagnoses in suspected patients, particularly in the context of family studies and for prenatal/preimplantation analysis. In addition, from these practical uses emerges the possibility to study genotype,phenotype relationships and investigate the molecular pathogenesis resulting from specific mutations or groups of mutations. In the present review we summarize current knowledge regarding genotype,phenotype relationships in three disorders of mitochondrial fatty acid oxidation: very-long chain acyl-CoA dehydrogenase (VLCAD, also ACADVL), medium-chain acyl-CoA dehydrogenase (MCAD, also ACADM), and short-chain acyl-CoA dehydrogenase (SCAD, also ACADS) deficiencies. On the basis of this knowledge we discuss current understanding of the structural implications of mutation type, as well as the modulating effect of the mitochondrial protein quality control systems, composed of molecular chaperones and intracellular proteases. We propose that the unraveling of the genetic and cellular determinants of the modulating effects of protein quality control systems may help to assess the balance between genetic and environmental factors in the clinical expression of a given mutation. The realization that the effect of the monogene, such as disease-causing mutations in the VLCAD, MCAD, and SCAD genes, may be modified by variations in other genes presages the need for profile analyses of additional genetic variations. The rapid development of mutation detection systems, such as the chip technologies, makes such profile analyses feasible. However, it remains to be seen to what extent mutation analysis will be used for diagnosis of fatty acid oxidation defects and other metabolic disorders. Hum Mutat 18:169,189, 2001. © 2001 Wiley-Liss, Inc. [source] Insulin-like 3 signalling in testicular descentINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 5 2004Ibrahim M. Adham Summary Undescended testis is one of the most common congenital defects in the newborn boys and the common cause of cryptorchidism. If left untreated, this condition is strongly associated with infertility and drastically increased risk of testicular cancer in adulthood. Testis position in developing males is defined by sexual dimorphic differentiation of two gonadal ligaments, gubernaculum and cranial suspensory ligament. Recent transgenic mouse studies identified testicular hormone insulin-like 3 (INSL3), and its receptor, GREAT/LGR8, as the critical regulators of the gubernacular differentiation. Mutation analysis of the two genes in patients with undescended testis revealed functionally deleterious mutations, which may be responsible for the abnormal phenotype in some of the patients. [source] Juvenile Paget's Disease: The Second Reported, Oldest Patient Is Homozygous for the TNFRSF11B "Balkan" Mutation (966_969delTGACinsCTT), Which Elevates Circulating Immunoreactive Osteoprotegerin Levels,,§¶JOURNAL OF BONE AND MINERAL RESEARCH, Issue 6 2007Michael P Whyte MD Abstract The oldest person (60 yr) with juvenile Paget's disease is homozygous for the TNFRSF11B mutation 966_969delTGACinsCTT. Elevated circulating levels of immunoreactive OPG and soluble RANKL accompany this genetic defect that truncates the OPG monomer, preventing formation of OPG homodimers. Introduction: Juvenile Paget's disease (JPD), a rare autosomal recessive disorder, features skeletal pain, fracture, and deformity from extremely rapid bone turnover. Deafness and sometimes retinopathy also occur. Most patients have diminished osteoprotegerin (OPG) inhibition of osteoclastogenesis caused by homozygous loss-of-function defects in TNFRSF11B, the gene that encodes OPG. Circulating immunoreactive OPG (iOPG) is undetectable with complete deletion of TNFRSF11B but normal with a 3-bp in-frame deletion. Materials and Methods: We summarize the clinical course of a 60-yr-old Greek man who is the second reported, oldest JPD patient, including his response to two decades of bisphosphonate therapy. Mutation analysis involved sequencing all exons and adjacent mRNA splice sites of TNFRSF11B. Over the past 4 yr, we used ELISAs to quantitate his serum iOPG and soluble RANKL (sRANKL) levels. Results: Our patient suffered progressive deafness and became legally blind, although elevated markers of bone turnover have been normal for 6 yr. He carries the same homozygous mutation in TNFRSF11B (966_969delTGACinsCTT) reported in a seemingly unrelated Greek boy and Croatian man who also have relatively mild JPD. This frame-shift deletes 79 carboxyterminal amino acids from the OPG monomer, including a cysteine residue necessary for homodimerization. Nevertheless, serum iOPG and sRANKL levels are persistently elevated. Conclusions: Homozygosity for the TNFRSF11B "Balkan" mutation (966_969delTGACinsCTT) causes JPD in the second reported, oldest patient. Elevated circulating iOPG and sRANKL levels complement evidence that this deletion/insertion omits a cysteine residue at the carboxyterminus needed for OPG homodimerization. [source] The correlation between alteration of p16 gene and clinical status in oral squamous cell carcinomaJOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 9 2001Chung-Hung Tsai Abstract: The purpose of the study was to evaluate the presence of alteration of the tumor suppressor gene p16 and to correlate these changes with the clinical status of the patients in oral squamous cell carcinoma. Forty-eight oral squamous cell carcinomas were included in the analyses. Deletion analysis was performed by the polymerase chain reaction (PCR). Mutation analysis was restricted to exon 1 and exon 2 of the p16 gene, previously shown to have a high incidence of mutations. The sequences containing exon 1 and exon 2 were amplified by PCR and screened with a single-strand conformation polymorphism (SSCP) technique. Samples showing band shifts in SSCP were sequenced by PCR direct sequencing. Western blots were used to detect the protein expression of the p16 gene, and the results were evaluated with regard to their biological relevance in correlation with clinicopathological factors. Seven (14.6%) deletions were found; 5 (10.4%) mutations were discovered and located in different codons; 26 (54%) specimens had no p16 protein expression; in 11 specimens with p16 deletion or mutation, p16 protein could not be detected. One mutation was non-sense. The p16 gene alterations showed no relationship with location and clinical stage of cancer; however, a close relationship between p16 alterations and cancer metastasis to neck lymph node was found. The alteration rate gradually elevated from well to poorly differentiated grades. We perceive two results. First, the alterations of the p16 gene are common in oral squamous cell carcinoma. Second, the alterations of the p16 gene may attribute to the metastatic behavior or histological grade of cancer cells. [source] Heterogeneous mutations of the ATP2C1 gene causing Hailey,Hailey disease in Hong Kong ChineseJOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 10 2010TS Cheng Abstract Background, Hailey,Hailey disease (HHD) is a rare autosomal dominant dermatosis. It causes suprabasilar acantholysis leading to vesicular and crusted erosions affecting the flexures. Mutation of ATP2C1 gene encoding the human secretory pathway Ca2+/Mn2+ -ATPase (hSPCA1) was identified to be the cause of this entity. Objective, The aim of this study was to study the mutational profile of the ATP2C1 gene in Hong Kong Chinese patients with HHD. Methods, Patients with the clinical diagnosis of HHD proven by skin biopsy were included in this study. Mutation analysis was performed in 17 Hong Kong Chinese patients with HHD. Results, Ten mutations in the ATP2C1 gene were found. Six of these were novel mutations. The novel mutations included a donor splice site mutation (IVS22+1G>A); a missense mutation (c.1049A>T); two deletion mutations (c.185_188delAGTT and c.923_925delAAG); an acceptor splice site mutation (IVS21-1G>C) and an insertion mutation (c.2454dupT). Conclusion, The six novel mutations provide additions to the HHD mutation database. No hot-spot mutation was found and high allelic heterogeneity was demonstrated in the Hong Kong Chinese patients. [source] Mutation analysis of 12 candidate genes for distal hereditary motor neuropathy type II (distal HMN II) linked to 12q24.3JOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 2 2002Joy Irobi Abstract Distal hereditary motor neuropathies (distal HMNs) are characterized by degeneration of anterior horn cells of the spinal cord resulting in muscle weakness and atrophy. Distal HMN type II is genetically linked to chromosome 12q24.3 and located within a 13 cM region flanked by D12S86 and D12S340. We previously excluded 5 positional and functional candidate genes for distal HMN II. Here, we report the exclusion of 12 additional candidate genes localized within the distal HMN II region; the genes include musashi (Drosophila) homolog 1 (MSI1), protein inhibitor of neuronal nitric oxide synthase (PIN), peripherin (PRPH), tubulin alpha ubiquitous (K-ALPHA-1), tubulin alpha 3 (TUBA3), tubulin alpha 6 (TUBA6), splicing factor arginine/serine-rich 9 (SFRS9), U5 snRNP 100 kd (U5-100K), putative chemokine receptor, GTP-binding protein (HM74), MondoA, cut (Drosophila)-like homeobox 2 (CUX2) and ADP-ribosylation factor 3 (ARF3). [source] Large-scale identification of serotype 4 Streptococcus pneumoniae virulence factorsMOLECULAR MICROBIOLOGY, Issue 5 2002David L. Hava Summary Streptococcus pneumoniae (the pneumococcus) is carried in the nasopharynx of healthy individuals, but can spread to other host sites and lead to pneumonia, bacteraemia, otitis media and meningitis. Although it is logical to think a priori that differential gene expression would contribute to the ability of this patho-gen to colonize different sites, in fact very few genes have been demonstrated to play tissue specific roles in virulence or carriage. Using signature-tagged mutagenesis to screen 6149 mariner -transposon insertion strains, we identified 387 mutants attenuated for infection in a murine model of pneumonia. Among these mutants are ones with disruptions in a number of putative tissue-specific transcriptional regulators, surface proteins, metabolic proteins and proteins of unknown function, most of which had not previously been associated with virulence. A subset of these, including most of those with insertions in putative transcriptional regulators, was examined for phenotypes in murine models of bacteraemia and nasopharyngeal carriage. Four classes of mutants defective in infection models of the: (I) lung, (II) lung and blood, (III) lung and nasopharynx, and (IV) all three tissues were identified, thus demonstrating the ex-istence of tissue-specific pneumococcal virulence factors. Included in these strains were two with disruptions in a genetic locus that putatively codes for a transcriptional regulator, three surface proteins and three sortase homologues. Mutation analysis revealed that three of the seven genes in this locus are virulence factors that are specific to mucosal surfaces. [source] Features of the blink reflex in individuals at risk for Huntington's diseaseMUSCLE AND NERVE, Issue 11 2001Marina de Tommaso MD Abstract The aim of the study was to correlate the features of the blink reflex (BR) with the genetic abnormalities and the clinical findings in patients with Huntington's disease (HD) and asymptomatic gene carriers. Twenty patients with HD and 20 relatives were studied. Mutation analysis was performed for the CAG expansion within the HD gene using HD 333,HD 447 as oligonucleotide primers. The BR was elicited transcutaneously by electrical stimulation of the right supraorbital nerve. The recovery curve of the R2 and R3 responses after a conditioning stimulus was evaluated. R2 latency and duration and R3 duration were significantly increased in HD patients and in presymptomatic carriers in comparison with controls; reduced R2 recovery was also clear in both HD and gene-carrier relatives. In HD patients, the R2 latency increase correlated significantly with the severity of facial chorea. The R2 abnormalities are probably caused by impaired suprasegmental control by the basal ganglia over brainstem interneurons, which may precede the onset of involuntary movements, probably conditioning the severity of facial chorea during development of the disease. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1520,1525, 2001 [source] Mutation analysis of hepcidin and ferroportin genes in Italian prospective blood donors with iron overload,AMERICAN JOURNAL OF HEMATOLOGY, Issue 9 2009Lorena Duca No abstract is available for this article. [source] Prenatal diagnosis of oculocutaneous albinism type II and novel mutations in two Chinese familiesPRENATAL DIAGNOSIS, Issue 6 2007Li Hongyi Abstract Objective The prenatal genetic diagnosis and counseling of oculocutaneous albinism type II (OCA2) by detecting mutations in the OCA2 gene Methods DNA samples were extracted from peripheral whole blood and amniocentesis-derived cells. Polymerase chain reaction and automatic sequence analysis were used to screen the OCA2 gene. Results Case 1: Two novel heterozygous mutations (p.N476D and p.Y827H) in the P gene were detected in the proband. Molecular prenatal diagnosis on fetal DNA revealed N476D. The pregnancy progressed uneventfully to a normal outcome. Case 2: Mutation analysis of the DNA of family 2 revealed compound heterozygosities for two novel P gene mutations (p.N476D and p.G775R). The pregnant female and the fetus each presented with a single P gene mutation (p.V443I and G775R, respectively). The pregnancy was continued. Conclusion This is the first report of prenatal diagnosis performed in families with oculocutaneous albinism type II (OCA2). Also, this report reveals three novel mutations of the P gene. Copyright © 2007 John Wiley & Sons, Ltd. [source] X-Linked dominant chondrodysplasia punctata: prenatal diagnosis and autopsy findingsPRENATAL DIAGNOSIS, Issue 13 2006Shalini Umranikar Abstract Objective To report our experience of the prenatal diagnosis of X-linked dominant chondrodysplasia punctata (CDPX2) and highlight its variable phenotypic presentation. Methods We report the sonographic features of three female fetuses affected with CDPX2. The ultrasound, radiographic and pathological findings were compared. Results Family 1: Two affected pregnancies, both terminated. Fetus 1: Presented with epiphyseal stippling involving the vertebrae, upper and lower limbs, asymmetric shortening of the long bones and flat facial profile. Fetus 2: Prenatal findings included premature epiphyseal stippling, paravertebral cartilaginous calcific foci, mild shortening of the long bones and flat facies. Mutation analysis of the mother and both fetuses revealed mutation in the emopamil-binding protein (EBP) gene. Family 2: Prenatal sonography showed scattered epiphyseal stippling, minimal vertebral segmentation anomalies, mild asymmetric limb shortening and flat facies. Female infant delivered at 39 weeks of gestation. Biochemical analysis in all three fetuses showed increased levels of serum 8(9)-cholestenol consistent with delta (8), delta (7)-isomerase deficiency and CDPX2. Conclusion Prenatal diagnosis of CDPX2 is difficult because of marked phenotypic variation. Epiphyseal stippling, ectopic paravertebral calcifications, asymmetric shortening of long bones and dysmorphic flattened facies are crucial for prenatal diagnosis. DNA analysis of the CDPX2 gene and biochemical determination of the serum 8(9)-cholestenol level are important for diagnosis, especially if future pregnancies are planned. Copyright © 2006 John Wiley & Sons, Ltd. [source] Rapid genetic analysis of oculocutaneous albinism (OCA1) using denaturing high performance liquid chromatography (DHPLC) systemPRENATAL DIAGNOSIS, Issue 5 2006Shin-Yu Lin Abstract Objectives To present the prenatal genetic diagnoses and counseling for two cases of oculocutaneous albinism (OCA) type I family by detection of mutations in the OCA1 gene by denaturing high performance liquid chromatography (DHPLC) system and a review of the literature. Methods All DNA samples were extracted from peripheral whole blood and amniocentesis-derived cells. Mutation analysis was performed for all five coding exons of the TYR gene, which were amplified by PCR. DHPLC was used for heteroduplex detection and sequence analysis was performed to demonstrate the mutation loci. Results Case 1: After sampling of blood from the family members and performing amniocentesis of the fetus, it was demonstrated that the affected boy and the female fetus were shown to be compound heterozygotes for mutations in the TYR gene. In addition, it was shown that the parents were carriers of the two mutations. However, the couple chose to keep the baby. Case 2: Mutation analysis of the DNA of the siblings revealed two heterozygous mutations in the TYR gene. Her husband is free of the disease. According to the principles of autosomal recessive inheritance, the incidence of affected offspring is very low. Conclusions Herein we introduce a novel application for molecular diagnostic of DHPLC coupled with direct sequencing, which can provide an effective and exact diagnosis in patients with albinism. Clinicians should be cognizant of the risk of OCA inheritance by the offspring through careful identification of genetic mutations and the inheritance mode, both important to ensure comprehensive genetic counseling. Copyright © 2006 John Wiley & Sons, Ltd. [source] | |||||||||||||||||||||||||||||||||||||