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Query: UMLS:C0025362 (mental retardation)
 15,878 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Aniridia can arise as part of the WAGR syndrome (Wilms tumour. aniridia, genitourinary anomalies, and mental retardation), due to a deletion or chromosomal region 11p13. We report a girl with a complete WAGR syndrome, whose brother presented hypospadias. Cytogenetic, FISH and molecular studies showed a deletion in one chromosome 11 of the patient. No cytogenetic rearrangement or deletion affecting the genes included in this region (PAX6 and WT1) were observed in her brother and parents. This excludes a higher risk than that of the general population for developing Wilms tumour in the brother and supports that the presence of WAGR syndrome in the patient and hypospadias in her brother is a chance association. We conclude that the identification and definition of the deletions in the WAGR region, which include the WT1 locus are important in order to identify a high tumour risk in infant patients with aniridia including those without other WAGR anomalies.
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PMID:Aniridia as part of a WAGR syndrome in a girl whose brother presented hypospadias. 1215 Feb 18

Poly-Y karyotypes, except for 47,XYY, are rare events in humans. For instance, Y chromosome tetrasomy has been reported 10 times, 2 of which were by structural rearrangement. We present a 2-year-and-4-month-old boy who was referred for cytogenetic assessment because of global psychomotor delay. The GTG- and CBG-banded karyotypes on PHA-stimulated lymphocytes showed two cell populations, one of them contained two identical isodicentric Y chromosomes, which was seen in 93% of metaphases analyzed, and a 45,X cell line (7%). This was confirmed by FISH with probes DYZ3 (recognizing the centromeric region of the Y chromosome), 91H4.5 (recognizing Yp11.2), and DYZ1 (recognizing Y heterochromatin in Yq12). The breakpoint has occurred near the telomeric end of the heterochromatic region. Therefore, the karyotype is mos 47,X,idic(Y)(q12)x2[123]/45,X[9]. This is the second time that such a karyotype has been reported. This chromosomal anomaly was formed most likely by a U-type exchange. Clinical features included speech delay, short stature, brachycephaly, large ears, bilateral epicanthal folds, hypertelorism, delayed teeth eruption, bilateral radio-ulnar synostosis, bilateral fifth finger clinodactyly, normal external genitalia, and impulsive behavior. The father had normal phenotype and karyotype. A review of the tetrasomy Y patients is presented. All patients with Y chromosome tetrasomy exhibit some degree of mental retardation, various skeletal abnormalities, and facial dysmorphism. Nevertheless, the correlation between karyotype and phenotype is not yet well defined since few cases have been reported. This clinical report will be helpful in defining the phenotypic range associated with tetrasomy Y.
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PMID:Tetrasomy Y by structural rearrangement: clinical report. 1221 Feb 99

Overgrowth is rarely associated with chromosomal imbalances. Here we report on four children from two unrelated families presenting with overgrowth and a terminal duplication of the long arm of chromosome 15 diagnosed using cytogenetic and FISH studies. In both cases, chromosome analysis of the parents showed a balanced translocation involving 15q26.1-qter. Molecular and cytogenetic studies showed three copies of the insulin-like growth factor 1 receptor (IGF1R) gene. This finding suggests that overgrowth observed in our patients might be causally related to a dosage effect of the IGF1R gene, in contrast to severe growth retardation observed in patients with terminal deletion of 15q. The present observation emphasises the importance of chromosome analysis in patients with overgrowth and mental retardation. Moreover, it further delineates a specific phenotype related to trisomy 15q26.1-qter with macrosomia at birth, overgrowth, macrocephaly and mild developmental delay being the major clinical features.
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PMID:Overgrowth and trisomy 15q26.1-qter including the IGF1 receptor gene: report of two families and review of the literature. 1240 1

We report on a female patient who had mosaic trisomy 9, presenting with severe scoliosis and mental retardation. Scoliosis is seldom reported in patients with mosaic trisomy 9 syndrome. FISH studies in our proband detected no trisomic cell line in the paravertebral muscle.
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PMID:Tissue specific mosaicism of trisomy 9 in a patient with severe torsion scoliosis. 1255 17

We report a 24-year-old woman with minor facial anomalies, mental retardation, seizures, and partial agenesis of the corpus callosum. Cytogenetic analysis showed a de novo terminal chromosome 1 long arm deletion. FISH with a panel of chromosome 1q42-qter bands-specific BAC and YAC clones located the breakpoint at the 1q42-q43 junction, with monosomy restricted to the 1q43 and 1q44 bands. The changing craniofacial phenotype of this patient with age is described as part of the del(1)(q) syndrome natural history. The patient's features are compared with those of other patients with similar deletions, and variable phenotypic findings due to different deleted chromosomal segments are discussed.
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PMID:FISH and cytogenetic characterization of a terminal chromosome 1q deletion: clinical case report and phenotypic implications. 1609 3

In this report we describe the case of an 11-year-old male with autism and mental retardation, presenting a tetrasomy of chromosome 3q. Cytogenetic analysis showed a mosaic for an unbalanced karyotype consisting of mos46,XY,add(12)(p13.3)(56)/46,XY(45). FISH using WCP and subtelomeric probes identified the extra material on 12p to be an inverted duplication of the distal segment of chromosome 3q. Anomalies in chromosome 3q have not been previously described in association with autism, although association with psychomotor delays and behavior problems has been frequently reported and are here further discussed. This chromosomal 3q segment is therefore likely to include genes involved in specific neurodevelopment pathways, and further analysis of the region is warranted for the identification of the molecular alterations that lead to the autistic features described.
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PMID:Partial tetrasomy of chromosome 3q and mosaicism in a child with autism. 1275 57

Chromosomal abnormalities, such as deletions and duplications, are characterized by specific and often complex phenotypes resulting from an imbalance in normal gene dosage. However, routine chromosome banding is not sensitive enough to detect subtle chromosome aberrations (<5-10 Mb). Array-based comparative genomic hybridization (array CGH) is a powerful new technology capable of identifying chromosomal imbalance at a high resolution by co-hybridizing differentially labeled test and control DNAs to a microarray of genomic clones. We used a previously assembled contig of large-insert clones that span 10.5 Mb of the most distal region of 1p36 to design a microarray. The array includes 97 clones from 1p36, 41 clones from the subtelomeric regions of all human chromosomes, and three clones from each of the X and Y chromosomes. We used this microarray to study 25 subjects with well-characterized deletions of 1p36. All array CGH results agree with the deletion sizes and locations of the breakpoints in these subjects as determined previously by FISH and microsatellite analyses. Terminal deletions, interstitial deletions, derivative chromosomes and complex rearrangements were also identified. We anticipate that array CGH will change the diagnostic approach to many congenital and acquired genetic diseases such as mental retardation, birth defects and cancer.
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PMID:Development of a comparative genomic hybridization microarray and demonstration of its utility with 25 well-characterized 1p36 deletions. 1291 73

We here describe a submicroscopic translocation affecting the subtelomeric regions of chromosomes 2q and 6q identified in a patient referred to us because of mental retardation, obesity, brachydactyly, and short stature. FISH analysis using subtelomeric probes showed a 46,XY,der(2)t(2;6)(q37.3;q26) in the propositus, and a balanced t(2;6) in his father and sister. FISH with region-specific genomic clones made it possible to map the 2q37.3 breakpoint precisely to the region covered by BAC 585E12, and the 6q26 breakpoint to between the regions encompassed by 414A5 and 480A20. The 2q subtelomeric deletion has often been found in patients with Albright hereditary osteodystrophy (AHO)-like syndrome but, to the best of our knowledge, the 2q37.3-qter monosomy ascertained in our patient is the smallest so far described within the syndrome's critical interval, and may thus enhance the search for the responsible genes.
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PMID:Narrowing the candidate region of Albright hereditary osteodystrophy-like syndrome by deletion mapping in a patient with an unbalanced cryptic translocation t(2;6)(q37.3;q26). 1296 29

Sotos syndrome (SoS) is an autosomal dominant overgrowth syndrome with characteristic craniofacial dysmorphic features and various degrees of mental retardation. We previously showed that haploinsufficiency of the NSD1 gene is the major cause of SoS, and submicroscopic deletions at 5q35, including NSD1, were found in about a half (20/42) of our patients examined. Since the first report, an additional 70 SoS cases consisting of 53 Japanese and 17 non-Japanese have been analyzed. We found 50 microdeletions (45%) and 16 point mutations (14%) among all the 112 cases. A large difference in the frequency of microdeletions between Japanese and non-Japanese patients was noted: 49 (52%) of the 95 Japanese patients and only one (6%) of the 17 non-Japanese had microdeletions. A sequence-based physical map was constructed to characterize the microdeletions. Most of the microdeletions were confirmed to be identical by FISH analysis. We identified highly homologous sequences, i.e., possible low copy repeats (LCRs), in regions flanking proximal and distal breakpoints of the common deletion, This suggests that LCRs may mediate the deletion. Such LCRs seem to be present in different populations. Thus the different frequency of microdeletions between Japanese and non-Japanese cases in our study may have been caused by patient-selection bias.
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PMID:Fifty microdeletions among 112 cases of Sotos syndrome: low copy repeats possibly mediate the common deletion. 1451 49

In this study we describe a 3-generation family carrying a (X;Y)(p22.3;q11.2) translocation in seven individuals of both sexes. Molecular analysis of the aberrant (X;Y)(p22.3;q11.2) chromosome was performed by FISH using X and Y-specific painting probes and also PCR amplification of the Y-specific sequences. Using these approaches it was demonstrated that the translocation resulted in a deletion of both X and Y pseudoautosomal regions. Moreover, using RBG banding it was shown that in all females the X-derivative chromosome was inactive in over 90% of mitoses. From the preliminary results obtained in this study we assumed that in this particular family the observed phenotype of the patients was caused by a deletion of the cluster of pseudoaotosomal genes responsible for the stature. More proximal loci, like STS or MRX49, were probably not deleted, since neither ichtyosis nor mental retardation was observed in this family.
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PMID:A familial X/Y translocation: cytogenetic and molecular study. 1456 57


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