Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0025362 (mental retardation)
 15,878 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An analytical description is presented of 942 mentally retarded persons from the county of West Zealand. The prevalence of mental retardation (i.e. persons who were registered with an IQ below 75) was 0.36%. Almost half of the patients were living in institutions. Of the patients 43% were women and 57% men. Important aetiological factors are listed. In almost one third of the patients, similar cases were present among the closest relatives; 30% of the patients were born as the fourth or subsequent child in the family; one sixth of the mothers were more than 35 years old at the birth of the handicapped child. Twenty-two percent of the patients with IQs below 50 had Down's syndrome. Seventeen percent of the patients had epilepsy had 11% cerebral palsy. In the central institution all patients had psychiatric or somatic complications.
 ...
PMID:Disease pattern among 942 mentally retarded persons in a Danish county. 15 88

There is increasing recognition that autism is a syndrome, not a disease entity. But it is not yet clear why some children develop autistic behavior more easily than others. It has been noted that autistic symptoms occur more frequently in children with mental retardation, blindness, congenital rubella, phenylketonuria, etc., and that there are very few cases of classical infantile autism in the general population. Very rarely has autism been associated with Down's syndrome. This is a report of a case of Down's syndrome and infantile autism.
 ...
PMID:A case of infantile autism associated with Down's syndrome. 15 85

Chromosome imbalance (aneusomy) is the leading known cause of both spontaneous abortion and mental retardation in human beings. The primary abnormality is thought to result from quantitative changes of transcription products from the unbalanced genetic material. To document this point, I compared chromosome 21-specific transcription in skin fibroblasts from subjects with monosomy 21, disomy 21 (normal), and trisomy 21 (Down syndrome). Polyadenylylated RNA [poly(A)-RNA], which is enriched in messenger and messenger-precursor RNA sequences, was isolated from the above fibroblast lines. Radioactive DNA (cDNA) complementary to these RNAs was synthesized with reverse transcriptase (RNA-dependent DNA polymerase). These cDNAs were hybridized with (i) DNA from a cell line with a mouse genome plus human chromosome 21 and (ii) mouse DNA. Subtraction of the amount of hybridization in experiment ii from that in experiment i yielded a measure of human chromosome 21-specific RNA sequences. The results were consistent with gene dosage at the transcriptional level; for monosomy 21-derived cDNA, 0.6% (of the total cDNA) hybridized specifically to human chromosome 21; for disomy 21-derived cDNA, 2% hybridized; and for trisomy 21-derived cDNA, 3% hybridized. Thus, for DNA sequences on chromosome 21 in human skin fibroblasts, transcription depends on DNA dosage. Characterization of the chromosome 21-specific RNA sequences quantitated in these experiments could help to elucidate the mechanisms by which abnormal karyotypes result in abnormal phenotypes.
 ...
PMID:Down syndrome: gene dosage at the transcriptional level in skin fibroblasts. 15 66

A total of 600 handicapped patients had dental rehabilitation under general anesthesia during an eight-year period. Handicaps included mental retardation, cerebral palsy, Down syndrome, seizure disorders, autism, cystic fibrosis, osteogenesis imperfecta, and muscular dystrophy. No significant complications developed in the majority of patients. This is attributed to thorough preoperative evaluation, appropriate anesthetic management, and vigilant postoperative observation.
 ...
PMID:Complications related to the administration of general anesthesia in 600 developmentally disabled dental patients. 15 47

Three girls with mosaic mongolism (46, XX/47, XX, +21) were followed cytogenetically and psychologically from the time of diagnosis at 8, 17 and 32 months of age, respectively, to the age of 13--15.5 years. All showed muscular hypotonia and hyperflexible joints at the time of diagnosis, but otherwise the physical characteristics of Down's syndrome were weakly expressed. The percentage of trisomic cells in the peripheral blood decresed with time, but were still higher in lymphocytes than in skin fibroblasts at the last investigation. Developmental milestones were delayed in all cases, and the developmental and intelligence quotients were decreased. Mental retardation was only slight in one of the cases (I.G. = 65 at the age of 14 years 8 months). The intelligence quotients showed declining trends with time. Social ability and school results tended to be better than could be expected from the test results.
 ...
PMID:A prospective psychological and cytogenetic study of three girls with mosaic mongolism. 15 51

Pseudocholinesterase activity and the phenotypes controlled by the E1 locus have been determined in a sample of 307 Down's syndrome patients and 206 patients suffering from nonspecific mental retardation and compared to those in the healthy population. Both groups of patients have an elevated frequency of phenotypes possessing the rate E1f allele. The mentally retarded patients have a higher mean pseudocholinesterase activity than those with Down's syndrome who, in turn, have activity than the healthy controls.
 ...
PMID:Pseudocholinesterase activity and E1 phenotypes in Down's syndrome and mental retardation. 15 60

Since mongoloids have been reported to differ from other patients with mental retardation by being virtually free of atheromatosis, we analysed plasma lipids and lipoproteins in twenty mongoloid and in twenty age-matched non-mongoloid mentally retarded patients living in the same institution. Plasma total cholesterol in the mongoloids did not differ significantly from that of the control group, but it was low in both groups in comparison with the Finnish population in general. Plasma total triglyceride concentration was higher (P less than 0.01) in the mongoloids than in the controls. This was reflected in higher VLDL-triglyceride and-cholesterol concentrations in the mongoloids. Plasma apolipoprotein B levels were higher (P less than 0.05) and the ratio of apolipoprotein A-1 to apolipoprotein B was lower (less than 0.05) in the mongoloids. The plasma lipid concentrations were in accordance with the significantly higher relative body weights in the mongoloid group. Blood pressure was slightly but significantly lower and cigarette smoking was less common in patients with Down's syndrome. Our results did not explain the reported lower frequency of atheromatosis in Down's syndrome.
 ...
PMID:Plasma lipids and lipoproteins in Down's syndrome. 16 Jun 10

The prevalence of antibody to hepatitis A virus (anti-HAV) was determined in 854 people living in a large institution for the mentally retarded in Melbourne. Altogether 638 (74.4%) of the subjects were found to have specific antibody detectable by solid-phase radioimmunoassay (SPRIA). No difference in antibody prevalence was observed between males and females; however, the prevalence was higher among subjects with Down syndrome (84.1%) than those of other forms of mental retardation (72.8%). In both groups there was an increase in prevalence of antibody with increasing age and duration of institutionalization. When compared with the open community, patients in this institution have a higher prevalence of antibody and appear to acquire their infections at an earlier age.
 ...
PMID:Prevalence of antibody to the hepatitis A virus in a large institution for the mentally retarded. 21 14

Visualization of the neuron in its entirety through the use of the rapid Golgi method has permitted detection of several pathobiological features of neurons that are intimately associated with profound mental retardation in infants and children. In cases of unclassified mental retardation, dendrites and particularly dendritic spines exhibit severe developmental abnormalities. Dendritic spines, the postsynaptic components of axospinodendritic synapses, may be absent or abnormally long and thin in retardates. Evidence is presented that some cases of progressive neurobehavioral deterioration in infancy and early childhood may be due to progressive degeneration of dendritic spine systems (dendritic spine "dysgenesis"). Golgi and electron microscopic studies of neurons in human and feline ganglioside storage diseases indicate that ganglioside accumulation in cortical neurons initiates several complex alterations in neuronal geometry and morphology. Small and medium pyramidal cells form massive structural compartments (meganeurites) that frequently give rise to secondary neurites and other embryonic growth processes. Meganeurites may possess spines and spine-synapses. Other cells such as large pyramidal neurons may exhibit many somatic spines, whereas intrinsic cells of the cortex (and caudate) are unaffected morphologically by ganglioside accumulation. It is suggested that neuronal geometry distortion and aberrant synaptogenesis are important factors in the onset of neuronal dysfunction in ganglioside storage disorders. These studies also point to an important role of gangliosides in neurite formation in immature mammalian cortical neurons. Perisomatic processes and somatic spines are normal morphological components of the cell body of Purkinje cells through the 28th fetal week of human gestation. By 36 weeks the Purkinje cell somas exhibit a smooth surface contour. Prominent polydendritic processes, perisomatic protuberances, and somatic spines are detectable by Golgi methods applied to Purkinje cells in Menkes' disease and Down's syndrome long after these somatic components should normally disappear. Thus Purkinje cell soma membrane differentiation is a particularly sensitive process that can provide information on mechanisms of site-specific membrane regulation.
 ...
PMID:Pathobiology of cortical neurons in metabolic and unclassified amentias. 21 50

The marked binding of antibodies specific for 5-methylcytidine to the short arm of chromosome 15 distinguishes this chromosome from the other human acrocentrics. This method has been used to study over 60 individuals including 12 who did not have Down's syndrome, but who did have an extra G-group sized acrocentric chromosome. In six cases the extra chromosome did not show intensive binding of anti-5-methylcytidine. In the other six cases, the extra chromosome contained a 5-methylcytidine rich band at each end indicating that both ends were derived from chromosome 15 and contained centromeric heterochromatin normally present on the short arm of chromosome 15. The duplication of short arm material in the abnormal chromosomes was confirmed in all cases by quinacrine staining, nucleolar organizer (Ag-AS) staining or C-banding. In three cases, the abnormal chromosome appeared to arise from two different chromosomes 15. Several possible mechanisms for the production of the abnormal chromosome are discussed. The individuals with this abnormal chromosome all showed some degree of mental retardation, but few common physical findings.
 ...
PMID:Preferential derivation of abnormal human G-group-like chromosomes from chromosome 15. 32 37


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>