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

Williams syndrome is a genetic disorder linked to cognitive and behavioral patterns of varying consistency; this study was conducted to clarify further the strengths and weaknesses of children with Williams syndrome. Fifteen subjects with the characteristic features of Williams syndrome were evaluated using the Stanford-Binet Intelligence Scale for Children, Fourth Edition; the Vineland Adaptive Behavior Scales, Interview Edition; and the Child Behavior Checklist. Cognitive skills ranged from the Moderate Range of Mental Retardation to the Low Average range, with relative strengths in nonverbal and quantitative reasoning. Adaptive skills were delayed, with strengths in communication and socialization. Behaviorally, clinically significant levels of attention problems, borderline-significant levels of social and thought problems, and significantly low levels of social contacts and structured activities were found. In contrast to the findings of many other studies of Williams syndrome, language skills and short-term memory skills were weak. Children with Williams syndrome may present a more evenly developed intellectual profile, with verbal and nonverbal skills being commensurate. In conclusion, a variety of cognitive, adaptive, and behavioral patterns have been shown to be possible in Williams syndrome; therefore, a single predictable cognitive or behavioral phenotype cannot be assumed.
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PMID:Cognitive, adaptive, and behavioral characteristics of Williams syndrome. 1005 Sep 77

In this study, we evaluated the prevalence of the fragile X syndrome in a cohort of 574 mentally retarded children. The only inclusion criterion was the diagnosis of mental retardation according to the DSM-IIIR classification. We used a PCR-based strategy for the diagnosis of fragile X syndrome to facilitate systematic screening. This diagnostic scheme is based on an initial PCR to eliminate most fragile X-negative patients followed by Southern blotting for fragile X syndrome diagnosis. Altogether, 403 boys and 171 girls were tested. The prevalence of this genetic disorder was 1.9% (11/574) in the whole cohort and 2.5% (10/403) in boys. Only one case of fragile X syndrome was detected among the 171 girls tested (0.6%). Clinical examination, especially in the youngest children, was often unremarkable, and the only reason for suspecting fragile X syndrome was the presence of mental retardation. Thus, a systematic screening for the fragile X syndrome in mentally retarded children seems justified because of the importance of a precise diagnosis in genetic counseling.
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PMID:Systematic screening for fragile X syndrome in a cohort of 574 mentally retarded children. 940 Nov 1

Rhizomelic chondrodysplasia punctata (RCDP) is a genetic disorder which is clinically characterized by rhizomelic shortening of the upper extremities, typical dysmorphic facial appearance, congenital contractures and severe growth and mental retardation. Patients with RCDP can be subdivided into three subgroups based on biochemical analyses and complementation studies. The largest subgroup contains patients with mutations in the PEX7 gene encoding the PTS2 receptor. This results in multiple peroxisomal abnormalities which includes a deficiency of acyl-CoA:dihydroxyacetonephosphate acyltransferase (DHAPAT), alkyl-dihydroxyacetonephosphate synthase (alkyl-DHAP synthase), peroxisomal 3-ketoacyl-CoA thiolase and phytanoyl-CoA hydroxylase, although there are differences in the extent of the deficiencies observed. Patients in the two other subgroups have been reported to be either deficient in the activity of DHAPAT (RCDP type 2) or alkyl-DHAP synthase (RCDP type 3) while no other abnormalities could be observed. To examine whether the gene encoding DHAPAT is mutated in patients with RCDP type 2, we determined the N-terminal amino acid sequence of the enzyme isolated from human placenta. Using this sequence as a query, we identified a 2040 bp open reading frame (ORF) in the human database of expressed sequence tags. Expression of this ORF in the yeast Saccharomyces cerevisiae showed that we have identified the DHAPAT cDNA. The deduced amino acid sequence revealed no PTS2 consensus sequence. In contrast DHAPAT appears to contain a putative PTS1 at the extreme C-terminus. All RCDP type 2 patients analyzed were found to contain mutations in their DHAPAT cDNA. This demonstrates that RCDP type 2 is the result of mutations in DHAPAT.
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PMID:Acyl-CoA:dihydroxyacetonephosphate acyltransferase: cloning of the human cDNA and resolution of the molecular basis in rhizomelic chondrodysplasia punctata type 2. 953 89

Three people applied for genetic counselling, but during the consultations the clinical geneticist discovered other problems for which advice could have been given but was not asked. This caused a serious dilemma. The first person was a woman who wanted to know the risks of epilepsy for her potential offspring, but then it became clear that she appeared to have Huntington's disease in the family. The second person was a man who wanted to know about the genetic risks for his offspring of a borderline psychiatric disorder, but the geneticist, seeing that the partner had severe limb defects, wondered whether these were caused by a genetic disorder. The third patient was a pregnant woman who came asking about the risks caused by mental retardation in one of her ancestors, but who appeared to be a heavy drinker and user of cocaine and ecstasy. In dealing with such 'secondary' problems, it should be kept in mind that persons seeking advice must decide for themselves whether or not they want to be informed regarding these problems or not.
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PMID:[Genetic counseling: should side issues become main issues?]. 954 32

Williams' syndrome (WS) is a rare genetic condition of autosomal dominant inheritance with varying penetrance, which consists of supravalvular aortic stenosis, a characteristic dysmorphic facies named "elf face", mental retardation and other clinical manifestations including transient infantile idiopathic hypercalcemia, growth retardation, and frequent dental problems. It usually presents sporadically, and there are only a few cases of family involvement reported in the literature. Recent studies show that mutations in the elastin gene at chromosome 7q11.23, which occur approximately in 90% of cases, could be the cause of the different clinical manifestations in this syndrome. In this paper we report a case of family involvement with five family members involved with WS (three siblings, the mother, and the siblings' maternal uncle) and all had cardiac structural disorders (supravalvular aortic stenosis being the most frequent), a characteristic face and a low intellectual coefficient. The complementary tests included blood chemistry, chest X-ray, and echocardiogram, which led to the diagnosis of the associated valve pathology. Three patients required therapeutic catheterism with Stent valve implant and valve prosthetic replacement to control cardiac manifestations.
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PMID:[William's syndrome. Report of a case with family involvement]. 955 23

The oculocerebrorenal syndrome of Lowe (OCRL) is an X-linked human genetic disorder characterized by mental retardation, congenital cataracts, and renal tubular dysfunction. The Lowe syndrome gene, OCRL1, encodes a phosphatidylinositol 4,5-bisphosphate 5-phosphatase in the Golgi complex. The pathogenesis of Lowe syndrome due to deficiency of a phosphatidylinositol 4,5-bisphosphate 5-phosphatase in the Golgi complex is unknown. We have used targeted disruption in embryonic stem cells to make mice deficient in Ocrl1, the mouse homologue for OCRL1, as an animal model for the disease. Surprisingly, mice deficient in Ocrl1 do not develop the congenital cataracts, renal Fanconi syndrome, or neurological abnormalities seen in the human disorder. We hypothesized that Ocrl1 deficiency is complemented in mice by inositol polyphosphate 5-phosphatase (Inpp5b), an autosomal gene that encodes a phosphatidylinositol bisphosphate 5-phosphatase highly homologous to Ocrl1. We created mice deficient in Inpp5b; the mice were viable and fertile without phenotype except for testicular degeneration in males beginning after sexual maturation. We crossed mice deficient in Ocrl1 to mice deficient in Inpp5b. No liveborn mice or embryos lacking both enzymes were found, demonstrating that Ocrl1 and Inpp5b have overlapping functions in mice and suggesting that the lack of phenotype in Ocrl1-deficient mice may be due to compensating Inpp5b function.
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PMID:Functional overlap between murine Inpp5b and Ocrl1 may explain why deficiency of the murine ortholog for OCRL1 does not cause Lowe syndrome in mice. 959 60

Lesch-Nyhan syndrome is a hereditary disorder of purine metabolism causing overproduction of uric acid and neurological problems including spasticity, choreoathetosis, mental retardation, and compulsive self-mutilation. The syndrome is caused by a defect in the enzyme hypoxanthine-guanine phosphoribosyltransferase (HPRT), which converts guanine and hypoxanthine to the nucleotides GMP and IMP. There is evidence that the neurological problems are due to an adverse effect of the HPRT deficiency on the survival and/or development of dopaminergic neurons, specifically. Here we report that HPRT-deficient PC12 mutants that have a normal or near normal dopamine content (55-97% of that of wild-type cells) fail to undergo neuronal differentiation induced by nerve growth factor (NGF) when the de novo pathway of purine synthesis is partially inhibited. However, nerve growth factor-induced differentiation is near normal under these conditions in PC12 HPRT-deficient mutants containing much lower dopamine levels (<8% of that of wild type cells), indicating a neurotoxic effect of the endogenous dopamine in the mutants. The degree of inhibition of the de novo pathway of purine synthesis was the same in both classes of HPRT-deficient mutants. Expression of BCl-2 in a PC12 mutant that has a normal dopamine content allowed partial NGF-induced differentiation suggesting that the apoptotic pathway might be involved in the failure of differentiation when the de novo pathway of purine synthesis is partially inhibited.
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PMID:Impaired differentiation of HPRT-deficient dopaminergic neurons: a possible mechanism underlying neuronal dysfunction in Lesch-Nyhan syndrome. 967 Sep 94

We report a patient with Prader-Willi syndrome (PWS) complicated by diabetes mellitus. PWS is a genetic disorder characterized by obesity, mental retardation and hypogonadism. Glucose intolerance in this syndrome is thought to be secondary to insulin resistance associated with morbid obesity. Therapy was directed primarily at decreasing insulin resistance and thereby improving glucose intolerance by the administration of troglitazone, which increases insulin sensitivity. Changes in glucose disposal rate assessed by euglycemic hyperinsulinemic clamp test were measured, as well as glucose and insulin responses to a 75 g-OGTT before and after troglitazone therapy. Glucose disposal rate increased by 36% and plasma glucose responses to 75 g-OGTT decreased by about 50% during 12 weeks of troglitazone therapy despite slight weight gain. Thus, troglitazone has beneficial effects on glycemic control by improving insulin sensitivity in patients with PWS complicated by diabetes mellitus.
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PMID:Troglitazone ameliorates insulin resistance in a diabetic patient with Prader-Willi syndrome. 992 52

Congenital insensitivity to pain with anhidrosis (CIPA) is a very rare genetic disorder of the peripheral nervous system characterized by recurrent episodes of unexplained fever, generalized anhidrosis, insensitivity to pain and temperature, and accompanied by self-mutilating behavior and mental retardation. We report on a 16 month-old boy with CIPA who exhibited these characteristic clinical features. A sural nerve biopsy revealed markedly reduced numbers of unmyelinated and small myelinated fibers, consistent with the characteristic features of CIPA.
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PMID:Congenital insensitivity to pain with anhidrosis: a case report. 1048 30

Hennekam syndrome is a rare, recently described genetic disorder in which facial anomalies and mental retardation accompany congenital lymphedema and intestinal lymphangiectasia. Several other somatic abnormalities have variously been described, as have milder degrees of lymphatic dysfunction. The authors herein describe a case of Hennekam syndrome in which the diagnostic difficulties were partially overcome by the judicious use of radionuclide scintigraphy to verify the lymphedematous component of the patient's presentation.
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PMID:Lymphoscintigraphic manifestations of Hennekam syndrome--a case report. 1060 68


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