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

We describe an adult male who was diagnosed with Down syndrome (DS) at 9 months of age, but had repeatedly normal karyotypes until recent mid-resolution chromosome studies showed a possible duplication of 21q22.13 to 21q22.3. The abnormality was investigated using fluorescent in situ hybridization (FISH) studies. These showed hybridization of a whole chromosome paint probe (wcp21, Oncor Coatasome 21) to the entire length of both chromosome 21 homologues and one very large hybridization signal of a cosmid contig probe localized within bands 21q22.13-21q22.2(LSI-21, Vysis) on the ?dup(21q) homologue. CGH analysis identified a ratio of 1.5 for the segment of chromosome 21 involving band 21q22, indicating a gain of part, or all, of the terminal band of chromosome 21. The karyotype was thus defined as 46,XY,?dup(21) (q22.13q22.2).ish dup(21)(LSI-21++,wcp21+). Common DS characteristics in our case and 12 previously reported cases with duplications involving chromosome 21 included mental retardation, fifth finger clinodactyly, open mouth and oblique eye fissures. Transverse palmar creases and congenital heart defects, seen in DS less than 40% of the time, were infrequent. Presence of these features did not appear to depend on the specific portion of chromosome 21 that was duplicated. A review of 18 additional clinical features showed no consistent phenotype-genotype correlations.
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PMID:Cryptic duplication of 21q in an individual with a clinical diagnosis of Down syndrome. 1145 76

Ring chromosome 22, a rare cytogenetic finding, was first described in 1968, and since then about 60 patients have been reported. We describe a new patient with ring chromosome 22 syndrome and discuss the common features of the previously reported cases. Our patient had the major features of this syndrome including mental retardation, hypotonia, motor delay, microcephaly, dysplastic large ears, lack of speech, and hyperactivity disorder. Magnetic resonance imaging findings also revealed an arachnoid cyst, found in the posterior cerebellum. In patients with ring chromosome 22, variable clinical manifestations may be seen due to the size of lost sequences near the telomere. By fluorescent in situ hybridization (FISH) technique, LSI DiGeorge/VCFS/ ARSA locus-specific probes are used to detect deleted sequences. We found that 22q11.2 regions were intact on both chromosomes 22, but 22q13.3 (Arylsulfatase A; ARSA region) was absent in the ring chromosome. As far as we know this is the first reported Turkish patient in the literature.
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PMID:A case with a ring chromosome 22. 1866 89

We present a girl with a terminal 22q duplication due to an unbalanced chromosomal translocation: 46, XX, der(22)(qter --> q13.31::p11 --> qter). She presented with mild to moderate mental retardation, autism spectrum disorder, microcephaly and mild dysmorphic facial features. Because of nasal speech and mental retardation, FISH analysis for the DiGeorge/VCFS region was performed. In this analysis, an extra signal for the control probe LSI ARSA (22q13) on the short arm of one of the chromosomes 22 revealed the terminal duplication 22qter. The duplication was confirmed by means of 1Mb array-CGH and further delineated as a 5.5 Mb region: 46, XX, dup(22)(q13.31qter)(CTA-268H5 --> CTB-99K24)x3. Important phenotypic variability has been described among patients with terminal 22q duplications. However, by considering the present patient and a careful selection of literature reports describing pure trisomy 22qter and comparably small duplicated regions 22q13.3 to qter, we find evidence for a consistent clinical presentation: mild to moderate mental retardation, microcephaly and similar mild dysmorphic features. Furthermore we conclude that small terminal duplications of chromosome 22q may be more common than generally assumed but may remain undetected by high resolution karyotyping. The application of array-CGH in patients with mental retardation and only very mild dysmorphism may allow to detect small 22qter duplications more frequently.
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PMID:A cryptic duplication 22q13.31 to qter leads to a distinct phenotype with mental retardation, microcephaly and mild facial dysmorphism. 1923 79

We report a girl with a de novo pure partial trisomy 21 with some clinical features of Down syndrome. The girl patient presented a flat broad face, brachycephaly, and a flat nasal bridge. She also had upwardly slanted palpebral fissures, epicanthal folds, blepharitis, brushfield spots, and strabismus. Her mouth was wide with downturned corners, prominent lower lip, narrow and furrowed tongue, and short palate. G-banded chromosomal analysis of metaphases in cells from both skin and blood showed a 46,XX karyotype with additional chromosomal material on the distal short arm of one chromosome 21. Parental chromosomes were normal. Molecular analyses with the short-tandem-repeat (STR) marker D21S2039 (interferon-alpha/beta receptor [IFNAR]) (21q22.1) showed a triallelic pattern. Subtelomeric fluorescent in situ hybridization (FISH) analyses, LSI 13 (retinoblastoma 1 [RB1])/LSI 21(21q22.13-q22.2), and whole chromosome painting probes specific for chromosome 21 showed trisomy for the segment 21q22.13-21q22.2 due to a de novo intrachromosomal duplication. A 500K SNP microarray analysis was then performed and revealed a 13-Mb duplication of 21q22.11-qter. This duplicated material had been translocated onto the end of the "p" arm of one of the chromosome 21s. The karyotype was provisionally defined as 46,XX,add(21)(p12).ish der (21)t(21;21)(p12;q22.11)(WCP21q+,PCP21q++,D215259/D21S341/D21S342++)dn. At the age of 4 years and 10 months, a comprehensive psychological examination was performed and the diagnostic criteria for mental retardation were not fulfilled. In comparison with previously published cases of pure partial trisomy 21, this is a rare finding. Additional studies of such rare patients should aid in the study of the pathogenesis of Down syndrome.
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PMID:Clinical, cytogenetic, and molecular characterization of a girl with some clinical features of Down syndrome resulting from a pure partial trisomy 21q22.11-qter due to a de novo intrachromosomal duplication. 2014 12

Marker chromosomes are very rare in Klinefelter patients and phenotypic findings are related to the affected chromosomal region. The phenotypic effects of small supernumerary marker chromosomes (sSMC) range from multiple malformations/mental retardation to no effect (ie a normal phenotype). This wide spectrum of phenotypes is due to the origin, structure and gene content of the marker chromosome. The first Klinefelter case with sSMC 9 was published by Liehr et al in 2005. The present case was referred for chromosomal analysis because of dysmorphic features, speech delay and mild mental retardation. Conventional cytogenetic analysis revealed the 47XXY karyotype in 17 metaphases and the 48 XXY + marker karyotype in eight metaphases. Fluorescence in situ hybridization (FISH) analysis to identify the marker chromosome was performed using the LSI p16 (9p21) Spectrum Orange/CEP 9 SpectrumGreen Probe (Vysis CDKN2A/CEP 9 FISH Probe) and partial trisomy 9 mosaicism was confirmed in this patient. To our knowledge, this is the second case of Klinefelter syndrome with a small supernumerary marker chromosome derived from chromosome 9.
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PMID:Another small supernumerary marker chromosome derived from chromosome 9 in a Klinefelter patient. 2402 Feb 36