Gene/Protein Disease Symptom Drug Enzyme Compound
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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 a 5-generation Hispanic family with 13 males and 1 female affected with MASA syndrome. The proposita, a 17-year-old female, and her affected male relatives shared many of the cognate manifestations--mental retardation (14/14), aphasia or delayed speech (13/13), shuffling gait (8/13), adduction of thumbs (14/14)--as well as scoliosis (2/13) and increased deep tendon reflexes in the lower extremities (10/13). Southern analysis with the polymorphic DNA probes DXS14 (Xp11), DXS72 (Xq21), and F8C (Xq28) confirmed linkage to the Xq28 region with a maximum lod score of 3.01 for this family.
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PMID:Clasped-thumb mental retardation (MASA) syndrome: confirmation of linkage to Xq28. 160 19

We report on 4 generations in a family with 3 living males, 3 males who died in infancy, and 3 females with neurologic impairment and agenesis of the corpus callosum (ACC). Manifestations in the surviving males include severe acquired micrencephaly, mental retardation, limb contractures, scoliosis, tapered digits with hyperconvex nails, a characteristic face with large eyes, prominent supraorbital ridges, synophris, optic atrophy, broad alveolar ridges and seizures. Urologic anomalies include renal dysplasia, cryptorchidism, and hypospadias. Two affected females were less severely impaired and continued to be socially responsive as adults, but had spastic quadriplegia and seizures. One obligate heterozygote was retarded with emotional problems while another obligate carrier female and her daughter were clinically normal. Pedigree analysis suggested X-linked inheritance with variable expression in females. These findings are inconsistent with the well-described X-linked conditions with ACC including FG syndrome and Aicairdi syndrome. ACC has not been described in Coffin-Lowry syndrome, a condition with similar clinical findings, which also demonstrates marked variability of expression in carrier females. In order to assist in carrier determination, brain imaging studies and DNA linkage analysis of the affected relatives was performed. We found a spectrum of agenesis of the corpus callosum with the most severe manifestations in the most severely affected males. DNA analysis using a series of X-linked probes suggests linkage with a LOD score of 1.26 at theta = 0 to a region between p 11.3 and p 21.3.
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PMID:New X-linked syndrome with seizures, acquired micrencephaly, and agenesis of the corpus callosum. 846 65

A family in which 6 males have X-linked mental retardation has been studied with polymorphic DNA probes. The males differ from unaffected males only in impaired intellect and in smaller head size. The gene that causes mental retardation in the family appears to be located in band Xq21 on the basis of linkage with 3 markers: DXS250, DXS345 and DXS3 (theta max = 0.00; Zmax = 1.6). A multipoint lod score of 2.36 was obtain with no recombination relative to DXS326 in Xq21. This family is considered to have nonspecific X-linked mental retardation and has been given the designation MRX8.
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PMID:MRX8: an X-linked mental retardation condition with linkage to Xq21. 160 27

The concept of anticipation, the occurrence of a genetic disorder at progressively earlier ages in successive generations, has been debated from the early years of this century, with myotonic dystrophy as the most striking example. Throughout most of this period there has been controversy as to whether the phenomenon resulted from observational and ascertainment biases or reflected a more fundamental mechanism. The recent discovery of inherited unstable DNA sequences, first in fragile-X mental retardation and now in myotonic dystrophy, not only confirms that anticipation indeed has a true biological basis but provides a specific molecular mechanism for it; this discovery can explain many of the puzzling anomalies in the inheritance of myotonic dystrophy and may prove relevant to comparable problems in other genetic disorders.
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PMID:Anticipation in myotonic dystrophy: new light on an old problem. 160 89

Neuronal ceroid lipofuscinosis (NCL, Batten disease) is an autosomal recessive disease characterized by progressive mental retardation, cortical atrophy, seizures, and retinal degeneration. Several subtypes have been delineated on the basis of age-at-onset and histological characteristics; the most common is the juvenile (JNCL) form. Recently, the gene for JNCL was shown to reside on chromosome 16 through linkage studies to the haptoglobin locus and anonymous DNA markers using numerous European families. We have now examined 8 families from North America with JNCL for linkage to markers in 16q21-23. Results in 3 families tend to support linkage to chromosome 16;3 families remained uninformative, and 2 families produced negative lod scores in this region. A test of homogeneity was suggestive, but could not significantly reject the null hypothesis of homogeneity. We are continuing to collect families, particularly those with multiple living affecteds, and are identifying other probes in this region. Given close localization on chromosome 16 for JNCL, molecular strategies, including candidate gene strategies, are being explored.
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PMID:Linkage analysis in juvenile neuronal ceroid lipofuscinosis. 160 35

DiGeorge syndrome in humans is characterized by immunodeficiency, heart defects, mental retardation and facial dysmorphism; cytogenetic analysis has shown that deletions at 22q11 occur in approximately 25% of cases. To generate DNA markers from this region, we have microdissected and microcloned band q11 of human Chromosome (Chr) 22. Nineteen thousand clones were obtained from material dissected from 20 chromosome fragments. Seventeen of 61 clones analyzed (28%) were repetitive, 27 (44%) gave no signal, and 17 (28%) detected single copy sequences of which ten mapped to Chr 22. Two of these were found to be deleted in patients with DiGeorge syndrome and either monosomy for 22q11-pter or visible interstitial deletions of 22q11. These two markers are also hemizygous in patients with no visible chromosomal abnormality, demonstrating that submicroscopic deletions are common in DiGeorge syndrome patients.
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PMID:Interstitial deletions in DiGeorge syndrome detected with microclones from 22q11. 161 13

Fragile X syndrome, associated with the fragile X chromosome, is the most common cause of familial mental retardation. A breakthrough has been made in molecular biological research into the fragile X site. In this review we describe the molecular investigations that have led to the isolation of the FMR-1 gene. The nature of the fragile X mutation as well as the implications of the DNA test for the mutation are discussed.
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PMID:The fragile X syndrome: isolation of the FMR-1 gene and characterization of the fragile X mutation. 161 21

A 2 8/12-year-old boy with severe growth failure and mental retardation was found to have a maternally derived tandem duplication of the long arm of X chromosome, dup(X) (q13.3----q21.2). Karyotypic interpretation was further confirmed in this patient by a double gene dose for red blood cell phosphoglycerate kinase. DNA replication study showed that the duplicated X chromosome was always late replicating in peripheral blood lymphocytes as well as in skin fibroblasts from the mother. Endocrine studies in the patient demonstrated growth hormone deficiency. Magnetic resonance imaging of the head then disclosed the empty sella syndrome. This appears to be the first report of a dup(Xq) patient associated with a growth hormone deficiency and the empty sella syndrome. We emphasize that duplication of the proximal Xq in males represents another microduplication syndrome (Thode-Leonard syndrome).
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PMID:Growth hormone deficiency and empty sella syndrome in a boy with dup(X) (q13.3----q21.2). 163 33

We describe a young man with a progressive neurological disorder including myoclonus, mental retardation, muscle weakness and a mitochondrial myopathy (myoclonus epilepsy and ragged red fibres--MERRF). Multiple abnormalities of the mitochondrial respiratory chain in skeletal muscle are shown by direct measurement of the flux through the individual complexes, low-temperature redox spectroscopy and decreased immunodetectable subunits of complexes I and IV by immunoblotting. No abnormality of mitochondrial DNA was found. This is the first report of combined defects of complexes I, III and IV as a cause of this clinical syndrome. However, we propose that the occurrence of multiple respiratory chain defects may be more common than previously recognised and that this particular combination of defects, involving complexes I, III and IV, may be the predominant biochemical abnormality in MERRF.
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PMID:Multiple defects of the mitochondrial respiratory chain in a mitochondrial encephalopathy (MERRF): a clinical, biochemical and molecular study. 164 12

Wilms' tumour (WT), aniridia, genitourinary abnormalities and mental retardation form a symptom group (WAGR syndrome) associated with hemizygous deletions of DNA in chromosome band 11p13 (refs 1,2). However, it has not been clear whether hemizygosity at a single locus contributes to more than one phenotype. The tumour suppressor gene for Wilms' tumour, WT1, has been characterized: it is expressed at high levels in the glomeruli of the kidney, as well as the gonadal ridge of the developing gonad, the Sertoli cells of the testis and the epithelial and granulosa cells of the ovary, suggesting a developmental role in the genital system in addition to the kidney. We now report constitutional mutations within the WT1 genes of two individuals with a combination of WT and genital abnormalities as evidence of a role for a recessive oncogene in mammalian development.
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PMID:WT1 mutations contribute to abnormal genital system development and hereditary Wilms' tumour. 165 25


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