Chromosomal Deletions (chromosomal + deletion)

Distribution by Scientific Domains
Life Sciences61%
Medical Sciences38%

Selected Abstracts

Molecular Genetic Study on Angelman Syndrome Patients without a Chromosomal Deletion

EPILEPSIA, Issue 2000
Shinji Saitoh
Purpose: Angelman syndrome (AS) is a ncurobehavioral disorder characterized by severe mental retardation, easily cvoked laughter, ataxic gait, and epilepsy. Epilepsy associated with AS is characterized by early childhood onset gencralized seizures with profound EEG abnormalities. Therefore, AS is a good human model for genetic epilepsy syndromes. Approximately 70% of AS cases are caused by maternal deletions of chromosomc 15q I I-qI3; whereas, 30% are not associated with a chromosomal dcletion. Thcse non-deletion AS patients are caused by paternal uniparental disomy (UPD), imprinting mutation (IM), or loss-or-function mutations of the UBE3A gene, cach of which predisposes different recurrence risk. To elucidate molecular etiology of non-dclction AS patients, we investigated 34 AS patients without a chromosomal deletion. Methods: Thirty sporadic AS patients, and 4 familial AS patients (2 families of 2 sibs) were enrolled to the study. The diagnosis of AS was based on Williams' criteria (Williams et al., Am J Med Genet 1995, 56: 237). Genomic DNA was extracted from peripheral blood by a standard procedure. DNA mcthylation tcst at SNRPN locus and genotyping using 7 highly informative PCR-based polymorphisms within 15q I I - q I3 were carried out to identify UPD and IM. When both UPD and IM were ruled out, the patients were classified :LS non-UPD, non-IM. For thcsc non-UPD, non-1M paticnts, UBE3A mutations were screened by PCR-SSCP analysis using 10 sets ofprimcrs covering all coding exons. Results: Among 30 sporadic patients, I UPD and 3 IM patients were identified, and the remaining 26 patients were classified as non-UPD, non-IM. Among 4 familial patients, 2 sibs from I family were detected as IM, whcrcas 2 sibs from another family were classified as non-UPD, non-IM. No UBE3A mutations were identified within 26 sporadic and 2 familial non-UPD, non-IM patients. Conclusion: Threc molecular classes were identified for noindeletion AS patients. Therefore, the underlying genetic mechanism was dcmonstratcd to be complex for AS patients without a chromosomal deletion. Combination of the DNA methylation test and PCR-based polymorphisms was sufficient to detect UPD and IM patients. Because recurrence risk is low for UPD and high lor IM, systematic molecular investigation including the DNA methylation test and PCR-based polymorphisms should bc donc for non-delction AS paticnts for genetic counscling purpose. A majority of non-deletion patients were classified as noii-UPD, non-1M. Although, approximate 30% of non-UPD, nonIM patients arc rcportcd to have UBE3A mutations, no such mutations were identified in our study. An underlying molecular mechanism was not rcvealcd for this group of patients, and therefore, assessment of recurrence risk was difficult. Further investigation is necessary for noii-UPD, non-1M paticnts. [source]

Patterns of chromosomal deletions identified by a birth defects registry, Hawaii, 1986,2003

CONGENITAL ANOMALIES, Issue 2 2007
Mathias B. Forrester
ABSTRACT The aim of the investigation was to describe the chromosomal deletions identified by a birth defects registry with respect to the chromosomes involved, pregnancy outcome, method of diagnosis, inheritance, sex, and the diagnosis of major structural birth defects. Cases were derived from a population-based birth defects registry in Hawaii and comprised all infants and fetuses with chromosomal deletions delivered during 1986,2003. A total of 71 cases were identified through a statewide birth defects registry in Hawaii during 1986,2003. The chromosomes involved in the greatest proportion of deletions were chromosomes 22 (14.1%), 4 (11.3%), and 5 (11.3%). Live births accounted for 58 (81.7%) of the cases. Diagnosis was made by amniocentesis or chorionic villus sampling in 19 (26.8%) of the cases. Of the 18 cases with known inheritance, the deletion was inherited in 5 (27.8%) and de novo in 13 (72.2%). Males accounted for 28 (39.4%) and females for 43 (60.6%) of the cases. Major structural birth defects were identified in 51 (71.8%) of the cases. Chromosomal deletions do not appear to affect all chromosomes equally. Most of the chromosomal deletions that were detected occurred among live births and were de novo conditions. Infants and fetuses with chromosomal deletions are more likely to be females and to be associated with major structural birth defects. [source]

Molecular Genetic Study on Angelman Syndrome Patients without a Chromosomal Deletion

EPILEPSIA, Issue 2000
Shinji Saitoh
Purpose: Angelman syndrome (AS) is a ncurobehavioral disorder characterized by severe mental retardation, easily cvoked laughter, ataxic gait, and epilepsy. Epilepsy associated with AS is characterized by early childhood onset gencralized seizures with profound EEG abnormalities. Therefore, AS is a good human model for genetic epilepsy syndromes. Approximately 70% of AS cases are caused by maternal deletions of chromosomc 15q I I-qI3; whereas, 30% are not associated with a chromosomal dcletion. Thcse non-deletion AS patients are caused by paternal uniparental disomy (UPD), imprinting mutation (IM), or loss-or-function mutations of the UBE3A gene, cach of which predisposes different recurrence risk. To elucidate molecular etiology of non-dclction AS patients, we investigated 34 AS patients without a chromosomal deletion. Methods: Thirty sporadic AS patients, and 4 familial AS patients (2 families of 2 sibs) were enrolled to the study. The diagnosis of AS was based on Williams' criteria (Williams et al., Am J Med Genet 1995, 56: 237). Genomic DNA was extracted from peripheral blood by a standard procedure. DNA mcthylation tcst at SNRPN locus and genotyping using 7 highly informative PCR-based polymorphisms within 15q I I - q I3 were carried out to identify UPD and IM. When both UPD and IM were ruled out, the patients were classified :LS non-UPD, non-IM. For thcsc non-UPD, non-1M paticnts, UBE3A mutations were screened by PCR-SSCP analysis using 10 sets ofprimcrs covering all coding exons. Results: Among 30 sporadic patients, I UPD and 3 IM patients were identified, and the remaining 26 patients were classified as non-UPD, non-IM. Among 4 familial patients, 2 sibs from I family were detected as IM, whcrcas 2 sibs from another family were classified as non-UPD, non-IM. No UBE3A mutations were identified within 26 sporadic and 2 familial non-UPD, non-IM patients. Conclusion: Threc molecular classes were identified for noindeletion AS patients. Therefore, the underlying genetic mechanism was dcmonstratcd to be complex for AS patients without a chromosomal deletion. Combination of the DNA methylation test and PCR-based polymorphisms was sufficient to detect UPD and IM patients. Because recurrence risk is low for UPD and high lor IM, systematic molecular investigation including the DNA methylation test and PCR-based polymorphisms should bc donc for non-delction AS paticnts for genetic counscling purpose. A majority of non-deletion patients were classified as noii-UPD, non-1M. Although, approximate 30% of non-UPD, nonIM patients arc rcportcd to have UBE3A mutations, no such mutations were identified in our study. An underlying molecular mechanism was not rcvealcd for this group of patients, and therefore, assessment of recurrence risk was difficult. Further investigation is necessary for noii-UPD, non-1M paticnts. [source]

Thermoregulation of the Escherichia coli O157:H7 pO157 ecf operon and lipid A myristoyl transferase activity involves intrinsically curved DNA

MOLECULAR MICROBIOLOGY, Issue 2 2004
Jang W. Yoon
Summary Escherichia coli O157:H7 survives in diverse environments from the ruminant gastrointestinal tract to cool nutrient-dilute water. We hypothesized that the gene regulation required for this flexibility includes intrinsically curved DNA that responds to environmental changes. Three intrinsically curved DNAs were cloned from the E. coli O157:H7 virulence plasmid (pO157), sequenced and designated Bent 1 through Bent 3 (BNT1, BNT2 and BNT3). Compared to BNT1 and BNT3, BNT2 had characteristics typical of intrinsically curved DNA including electrophoretic gel retardation at 4°C, six partially phased adenine:thymine tracts and transcriptional activation. BNT2::lacZ operon fusions showed that BNT2 activated transcription at 24°C compared to 37°C and was partially repressed by a bacterial nucleoid-associated protein H-NS. BNT2 regulated the E. coli attaching and effacing gene-positive conserved fragments 1,4 (ecf1,4) that are conserved in Shiga toxin-producing E. coli associated with human disease. Experimental analyses showed that ecf1,4 formed an operon. ecf1, 2 and 3 encoded putative proteins associated with bacterial surface polysaccharide biosynthesis and invasion and ecf4 complemented a chromosomal deletion of lpxM encoding lipid A myristoyl transferase. Mass spectrometric analysis of lipid A from ecf and lpxM single and double mutants showed that myristoylation was altered at lower temperature. [source]

14q32/miRNA Clusters loss of heterozygosity in acute lymphoblastic leukemia is associated with up-regulation of BCL11a,

AMERICAN JOURNAL OF HEMATOLOGY, Issue 8 2010
Cecilia Agueli
This study evaluated the loss and expression level of miRNAs 14q32 clusters in acute lymphoblastic leukemia (ALL) patients with cryptic deletions at 14q32 chromosomal band to investigate their involvement in this disease. We demonstrate that a subset of ALL cases bearing 14q32 LOH showed a down-regulation of miRNA 14q32 clusters, which is directly linked to the submicroscopic chromosomal deletion. As a consequence of miRNAs deregulation we reported an inverse correlation with the expression of their target BCL11a, a transcription factor involved in lymphoid differentiation. These results suggest that 14q32/miRNA clusters LOH may be another mechanism involved in lymphoid B cell transformation and differentiation and therefore, could be used as a diagnostic marker and therapeutic target in subsets of ALL. Am. J. Hematol., 2010. © 2010 Wiley-Liss, Inc. [source]

Perinatal findings and molecular cytogenetic analyses of de novo interstitial deletion of 9q (9q22.3,q31.3) associated with Gorlin syndrome

PRENATAL DIAGNOSIS, Issue 8 2006
Chih-Ping Chen
Abstract Objectives To present the perinatal findings and the molecular cytogenetic analyses of a de novo interstitial deletion of 9q (9q22.3,q31.3) associated with Gorlin syndrome. Methods Amniocentesis was performed at 18 weeks' gestation on a 27-year-old woman at a community hospital because of a high Down syndrome risk of 1/178, a low maternal serum ,-fetoprotein (MSAFP) level of 0.66 multiples of the median (MoM), and a high maternal serum human chorionic gonadotrophin (MShCG) level of 3.13 MoM. The karyotype was initially determined to be 46,XY. However, fetal macrocephaly and overgrowth were found at 30 weeks' gestation. Postnatally, the infant manifested characteristic features of Gorlin syndrome. High-resolution chromosomal bandings of the peripheral blood lymphocytes, polymorphic DNA marker analysis to determine the parental origin of the deletion, array comparative genomic hybridization (CGH) to determine the extent of the chromosomal deletion, and fluorescence in situ hybridization (FISH) to determine the deletion of the PTCH gene were performed. Results The 850-band level of resolution showed an interstitial deletion of 9q (9q22.3,q31.3). The parental karyotypes were normal. The karyotype of the proband was 46,XY,del(9)(q22.3q31.3)de novo. Polymorphic DNA marker analysis revealed that the deletion was of paternal origin. Array CGH revealed that the deleted region was about 12 Mb, encompassing the segment from 9q22.32 to 9q31.3. FISH analysis using the BAC probe RP11-34D4 and the probe RP11-43505 indicated the deletion of the PTCH gene. Conclusions Fetuses with an interstitial deletion of 9q (9q22.3,q31.3) may be associated with a low level of MSAFP and a high level of MShCG in the second trimester, and sonographic findings of overgrowth and macrocephaly in the third trimester. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Deletion 15q24-26 in prenatally detected diaphragmatic hernia: increasing evidence of a candidate region for diaphragmatic development

PRENATAL DIAGNOSIS, Issue 4 2001
D. Schlembach
Abstract Survival of children with congenital diaphragmatic hernia (CDH) is mainly dependent on the extent of lung hypoplasia and the presence of additional congenital anomalies or chromosomal aberrations. A chromosomal deletion 15q25-q26.2 in a fetus with prenatally diagnosed CDH and growth retardation is reported. Despite optimal pre- and neonatal management the baby died shortly after birth. There is increasing evidence that the long arm of chromosome 15, and especially the region 15q24 to 15q26, plays a crucial role in the development of the diaphragm. The finding of a deletion within 15q24-26 in a fetus with CDH has to be considered a predictor of poor prognosis. It is of utmost interest for proper parental counselling to search in fetuses with CDH for subtle chromosomal lesions paying special attention to chromosome 15q. Copyright © 2001 John Wiley & Sons, Ltd. [source]

Patterns of chromosomal deletions identified by a birth defects registry, Hawaii, 1986,2003

CONGENITAL ANOMALIES, Issue 2 2007
Mathias B. Forrester
ABSTRACT The aim of the investigation was to describe the chromosomal deletions identified by a birth defects registry with respect to the chromosomes involved, pregnancy outcome, method of diagnosis, inheritance, sex, and the diagnosis of major structural birth defects. Cases were derived from a population-based birth defects registry in Hawaii and comprised all infants and fetuses with chromosomal deletions delivered during 1986,2003. A total of 71 cases were identified through a statewide birth defects registry in Hawaii during 1986,2003. The chromosomes involved in the greatest proportion of deletions were chromosomes 22 (14.1%), 4 (11.3%), and 5 (11.3%). Live births accounted for 58 (81.7%) of the cases. Diagnosis was made by amniocentesis or chorionic villus sampling in 19 (26.8%) of the cases. Of the 18 cases with known inheritance, the deletion was inherited in 5 (27.8%) and de novo in 13 (72.2%). Males accounted for 28 (39.4%) and females for 43 (60.6%) of the cases. Major structural birth defects were identified in 51 (71.8%) of the cases. Chromosomal deletions do not appear to affect all chromosomes equally. Most of the chromosomal deletions that were detected occurred among live births and were de novo conditions. Infants and fetuses with chromosomal deletions are more likely to be females and to be associated with major structural birth defects. [source]

Rapid detection of submicroscopic chromosomal rearrangements in children with multiple congenital anomalies using high density oligonucleotide arrays,,

HUMAN MUTATION, Issue 5 2006
Jeffrey E. Ming
Abstract Chromosomal rearrangements such as microdeletions and interstitial duplications are the underlying cause of many human genetic disorders. These disorders can manifest in the form of multiple congenital anomalies (MCA), which are a significant cause of morbidity and mortality in children. The major limitations of cytogenetic tests currently used for the detection of such chromosomal rearrangements are low resolution and limited coverage of the genome. Thus, it is likely that children with MCA may have submicroscopic chromosomal rearrangements that are not detectable by current techniques. We report the use of a commercially available, oligonucleotide-based microarray for genome-wide analysis of copy number alterations. First, we validated the microarray in patients with known chromosomal rearrangements. Next, we identified previously undetected, de novo chromosomal deletions in patients with MCA who have had a normal high-resolution karyotype and subtelomeric fluorescence in situ hybridization (FISH) analysis. These findings indicate that high-density, oligonucleotide-based microarrays can be successfully used as tools for the detection of chromosomal rearrangement in clinical samples. Their higher resolution and commercial availability make this type of microarray highly desirable for application in the diagnosis of patients with multiple congenital defects. Hum Mutat 27(5), 467,473, 2006. © Published 2006 Wiley-Liss, Inc. [source]

Mapping of IS6110 flanking regions in clinical isolates of Mycobacterium tuberculosis demonstrates genome plasticity

MOLECULAR MICROBIOLOGY, Issue 6 2000
R. M. Warren
Southern hybridization was used in combination with IS6110 insertion-locus-specific probes in a comparative study to determine the structure of chromosomal domains flanking IS6110 elements in clinical isolates of Mycobacterium tuberculosis. The resulting restriction fragment length polymorphism (RFLP) data demonstrated three mutational mechanisms responsible for the polymorphisms observed: IS6110 insertion, chromosomal mutation and deletion. The frequency of IS6110 insertion within many of the chromosomal regions demonstrates that preferential integration regions are common in M. tuberculosis. Mapping the IS6110 insertion positions and chromosomal deletions in relation to the M. tuberculosis H37Rv and M. bovis BCG genome sequences reveals numerous disruptions of predicted open reading frames (ORFs). A phylogenetic tree, based on the mutational data, showed a number of independently evolving lineages of M. tuberculosis, while analysis of the mutational events occurring at each branch point suggests both divergent and convergent evolution. A significant positive correlation was demonstrated between the mutation rate and the frequency of occurrence of different isolates in families of strains, suggesting that evolution may impact on strain ,fitness' or that strain proliferation may increase the chance of mutation. We conclude that the genome of clinical isolates of M. tuberculosis continues to evolve. [source]

Dystonia in a patient with ring chromosome 21,

MOVEMENT DISORDERS, Issue 12 2003
Craig E. Hou MD
Abstract Dystonia associated with chromosomal abnormalities is typically attributed to chromosomal deletions. We describe a patient with ring chromosome 21, with karyotype 46XX,r(21)(p11.2q22.3); 46,XX,dic r(21)(p11.2q22.3); 45, XX, ,21, who developed childhood onset cervical dystonia. © 2003 Movement Disorder Society [source]

The concomitant occurrence of multiple epidermal cysts, osteomas and thyroid gland nodules is not diagnostic for Gardner syndrome in the absence of intestinal polyposis: a clinical and genetic report

BRITISH JOURNAL OF DERMATOLOGY, Issue 4 2003
S.-M. Herrmann
Summary Gardner syndrome, a phenotypic variant of familial adenomatous polyposis, is characterized by the classical clinical triad of skin and soft tissue tumours, osteomas and intestinal polyposis, but disease patterns with pairs of these findings have also been reported. Different mutations in the adenomatous polyposis coli (APC) gene have been shown to be associated with Gardner syndrome disease phenotypes. A 36-year-old patient presented with multiple epidermal cysts on the face, left ear lobe and neck, and the possible diagnosis of Gardner syndrome was based on the additional findings of two classical osteomas in the left radius and ulna and a cold non-malignant nodule of the thyroid gland. Intestinal polyposis was lacking at the time of examination. Major deletions but not microdeletions were excluded by a cytogenetic analysis with 650 chromosomal bands per haploid set. Systematic sequencing of the entire coding region of the APC gene (> 8500 bp) of the patient and five healthy controls was also performed. As a results, new APC gene polymorphisms were identified in exons 13 [A545A (A/G)] and 15 [G1678G (A/G), S1756S (G/T), P1960P (A/G)]. We also detected D1822V (A/T) which has recently been reported to be potentially related to colorectal carcinoma, and genotyped 194 randomly chosen healthy individuals from the Glasgow area for this as well as for the above variants in exons 13 and 15. Interestingly, of the 194 controls, 112 carried the DD (57·7%), 71 the DV (36·6%), and the remaining 11 (5·7%), including our patient, the VV genotype. It is therefore unlikely that APC D1822V serves as an important marker for colorectal carcinoma. In conclusion, we failed to identify obvious germline candidate mutations in >,8500 bp of the coding region of the APC gene in a patient with multiple epidermal cysts, osteomas and a thyroid gland nodule; major chromosomal deletions were excluded. Therefore, we assume that only the presence of intestinal polyposis is a marker for Gardner syndrome. [source]