Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0917816 (mental retardation)
 15,867 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cognitive impairment occurs in one-third of patients with Duchenne muscular dystrophy, a lethal X-linked, recessive disease caused by mutations in the dystrophin gene which is expressed in both brain and muscle, the two transcripts having alternative first exons. Previous reports have indicated that the 'brain-type' dystrophin transcript predominates in brain. Using in situ hybridisation with antisense oligonucleotides, expression of four distinct mRNAs in specific brain areas is demonstrated here; the 14 kb muscle-type and brain-type transcripts were found to coexist in cortical and hippocampal neurons and two new transcripts have been identified in dentate gyrus and cerebellar Purkinje neurons, respectively. The latter has a novel first exon which was isolated and sequenced from mouse and human, and which would encode a protein with a different amino-terminus from the known muscle- and brain-type isoforms. Mapping in human located this exon in a large intron between the muscle-type promoter and second exon of the dystrophin gene. This finding of four alternative transcripts regulated by different promoters in brain reveals a new complexity to dystrophin expression that may have important insights for mental retardation mechanisms.
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PMID:Expression of four alternative dystrophin transcripts in brain regions regulated by different promoters. 130 51

We describe a mother and daughter with a distinct phenotype that is different from previous reports. This is likely to constitute a new syndrome for which we propose the mnemonic GMS for G goniodysgenesis, M mental deficiency, and S short stature. The pattern of occurrence is compatible with either autosomal dominant or X-linked inheritance.
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PMID:GMS syndrome: a new dominant condition with goniodysgenesis, mental retardation, and short stature. 130 45

X-Linked Mental Retardation constitutes an important pathologic entity in genetics. The overall significance, history and background of the concept of X-Linked mental retardation is reviewed with a special mention to the cases referenced under the term non-specific X-Linked mental retardation. The concept of lod-score has brought some improvement in the clinical delineation of the X-Linked mental retardation syndromes with some recent reports of suggestive linkage studies. The fragile-X syndrome is discussed with a special focus on reports of X-linked mental retardation with X chromosomal deletions or duplications. Linkage and molecular studies are reported viewing genetic approaches based on restriction fragment length polymorphisms. DNA probes spanning the length of the X and Y chromosomes which may prove critical to the development of diagnostic tests are referred. Computer assistance for a compilation of clinical findings in the X-linked mental retardation syndromes is specified as a diagnostic review and assistance program to check on the various entities. A joint collaborative investigation is reported to ascertain families with X-linked mental retardation in order to develop direct and linkage studies for the diagnosis of there disorders.
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PMID:[Various genetic aspects of X-linked mental retardation]. 134 94

Linkage analysis was performed in a family with nonspecific X-linked mental retardation (MRX). Affected individuals had no clinical characteristics other than mental retardation. Linkage was detected to the marker loci DXS477, DXS465, DXS52, DXS15 and F8C with maximum lod scores of 1.70, 1.32, 2.52, 1.70, and 1.09, respectively (theta = 0.0). The results strongly indicate that the gene for mental retardation in the family studied maps close to DXS52.
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PMID:Linkage to Xq28 in a family with nonspecific X-linked mental retardation. 136 58

The P-20 intragenic marker was used to test for restriction fragment length polymorphisms in unrelated Chinese patients with Duchenne or Becker muscular dystrophy or X-linked mental retardation. In addition to polymorphism at the 6.0/3.5 kb MspI allelic site, we found an independent and high frequency of polymorphism at the 2.2/1.8 kb site. This differs from results found with other populations.
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PMID:Significantly higher frequency of the MspI 2.2 kb allele of the Duchenne muscular dystrophy intragenic probe P-20 in the Chinese population. 138 93

X-linked hydrocephalus-stenosis of the aqueduct of Sylvius sequence (H-SAS, MIM number 30007) is a rare genetic disorder characterized by hydrocephalus, macrocephaly, adducted thumbs, spasticity, agenesis of corpus callosum and mental retardation. We confirm here the localisation of the mutant gene on Xq (Xq 2.8) by linkage analysis in a 5-generation pedigree (maximum lod score of Z = 4.57 at theta = 0.04 with probe St14 at locus DXS52) and emphasise the phenotypic variability of the disease. Ventricular dilatation in affected males was either severe and diagnosed antenatally or moderate and consistent with a long survival with little or no macrocephaly. Since other X-linked syndromes of mental retardation with spasticity and flexion deformities of the thumbs have previously been shown to map to the Xq 2.8 region as well (e.g. MASA syndrome and spastic paraplegia), the present results raise the question of whether H-SAS syndrome, MASA syndrome and spastic paraplegia with mental retardation might represent different phenotypic expression of various mutations at the same locus.
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PMID:X-linked hydrocephalus: clinical heterogeneity at a single gene locus. 139 13

Simpson-Golabi-Behmel Syndrome (SGBS), an X-linked encephalo-tropho-schisis syndrome described in fewer than a dozen families, is characterized by pre- and postnatal overgrowth, "coarse" face, minor facial anomalies and, in more severe cases, multiple congenital anomalies and mental retardation. We report on 2 brothers with overgrowth, macrocephaly, polydactyly, supernumerary nipples, and characteristic facial appearance. In addition, the propositus also had pulmonic stenosis and a cleft palate. The findings present in our patients are compared to those in the original patients and to those in patients described more recently. Despite the fact that our patients have most of the minor and several of the more severe malformations, they are not mentally retarded.
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PMID:Report of another family with Simpson-Golabi-Behmel syndrome and a review of the literature. 145 79

This report describes a new syndrome of dysgenesis of corpus callosum with other anomalies, presenting as microcephaly, mental retardation, spasticity, and unusual facial appearance in 2 Chinese brothers and their maternal cousins. To date, there has not been any case reported in the Chinese population of this syndrome. All 4 patients in this report present with the same unusual face. Hydrocephalus and/or interhemispheric cyst were found among them. This syndrome is transmitted as an X-linked trait. The nosology is reviewed and discussed.
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PMID:X-linked recessive inheritance of dysgenesis of corpus callosum in a Chinese family. 148 21

Linkage studies and cytogenetically visible deletions associated with nonspecific X-linked mental retardation (XLMR) and a specific form of deafness (DFN3) have indicated that the genes responsible for these disorders are located at Xq21. Using DNA probes from this region, we have studied several overlapping deletions spanning different parts of Xq21. This has enabled us to assign the DFN3 gene and a gene for nonspecific XLMR to an interval that encompasses the locus DXS232 and that is flanked by DXS26 and DXS121.
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PMID:Physical fine mapping of genes underlying X-linked deafness and non fra (X)-X-linked mental retardation at Xq21. 151 79

The Lowe oculocerebrorenal syndrome (OCRL; McKusick 309000) is an X-linked disorder characterized by congenital cataracts, muscular hypotonia, mental retardation, and Fanconi syndrome of the renal tubules. A pair of yeast artificial chromosomes (YACs) that span the Xq25-q26 translocation breakpoint in a female with OCRL were used as probes to screen cDNA libraries made from bovine lens and human kidney. The methods used to prepare the YACs as probes and to screen the libraries are presented in detail. Two different transcripts were found that map to the region around the Xq25-q26 breakpoint. These transcripts are now being studied to determine whether one or the other is a candidate gene for OCRL.
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PMID:Isolation of cDNA sequences around the chromosomal breakpoint in a female with Lowe syndrome by direct screening of cDNA libraries with yeast artificial chromosomes. 152 13


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