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)

Axonal swellings and spheroids in various human diseases were studied by light and electron microscopy. 4 cases of infantile neuroaxonal dystrophy, 2 of degenerative diseases, 2 brain tumors and 3 of cerebrovascular disease were examined. Ultrastructurally most spheroids in infantile neuroaxonal dystrophy consisted of interconnected tubules, stacked membranotubular profiles, alternating layered membranes and accumulations of neurofilaments. Combinations of these four constituents were seen only in infantile neuroaxonal dystrophy. "Torpedos" (fusiform swelling of the axon of a Purkinje cell) consisted exclusively of neurofilaments. Spheroids in case 6 (mental retardation) and 7 (atypical teratoma) consisted of interwoven skeins of neurofilaments and grouped mitochondria. Spheroids in case 8 (demyelination) and 9 (cerebrovascular disease) consisted of packed complex bodies and mitochondria. Spheroids in cases 10 and 11 (cerebrovascular disease) consisted of degenerating organelles only. The morphological differences between cases 9, 10 and 11 probably depends on the severity and timing of the cerebral injury. Most spheroids show similar histological and histochemical properties, but ultrastructural study may give some clue to the origin of the bodies.
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PMID:Morphological investigations on axonal swellings and spheroids in various human diseases. 15 Jan 8

Retarded body and brain growth and a deficit of myelin in the cerebral hemispheres and the cerebellum were observed in an animal model of phenylketonuria, the p-chlorophenylalanine and L-phenylalanine treated preweanling rat. These manifestations of phenylketonuria were reproduced in rats treated with phenylacetate in amounts approximating those likely to be produced in phenylketonuria. Young rats treated with equivalent amounts of other metabolites of phenylalanine, namely, phenylpyruvate, phenyllactate, and mandelate, which also accumulate in the brain during hyperphenylalaninemia, did not exhibit any toxic effects. Phenylpyruvate did not give rise to phenylacetate in the brain, but a small percentage was converted to phenyllactate. The gross composition of myelin isolated from the brains of saline and phenylacetate treated animals was similar. At various time intervals after subcutaneous injection, phenylacetate in the brain reached levels thirty times those of phenylpyruvate and phenyllactate, although animals received equivalent amounts of the three metabolites. The retarded growth of the body and brain of the young animal treated with phenylacetate may be attributed to the formation of phenylacetylcoenzyme A in the tissues. The site of action is very likely linked to acylcoenzyme A metabolism, i.e., the synthesis and utilization of acetylCoA and acetoacetylCoA, which are involved in reactions generating ATP and energy and in the synthesis of cholesterol and fatty acids. Results of this investigation indicate that growth retardation induced by phenylacetate during the period of very rapid development of the brain is responsible for the mental retardation in phenylketonuria.
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PMID:Myelin deficiency in experimental phenylketonuria: contribution of the aromatic acid metabolites of phenylalanine. 15 97

The relations between chromosomal diseases and mental retardation can be envisaged in three different ways: 1) Pharmacological approach shows a peculiar sensitivity of the cholinergic system in trisomic 21 children. A trouble in the manufacture of cholinergic mediator is plausible. 2) General biochemistry shows a slight shift of the glycolytic pathway in trisomics 21 as well as some localised abnormalities of amino-acids. 3) Gene mapping allows the localisation of the main responsable genes on band q22. 1 and among them the gene coding for superoxide dismutase 1. Also glutathion peroxidase is elevated. These disparate facts are discussed in the light of a model of the machinery regulating the production of chemical mediators. Comparison with other diseases lead to the hypothesis that rather simple and localised mechanisms could be specially important.
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PMID:[Chromosomal anomalies and intelligence deficiency (author's transl)]. 15 20

Tuberous sclerosis is a rare disease in which hamartomas may be found in the brain, the retina, the skin and in other internal organs. The classic form of the disease showing mental retardation, epilepsy and adenoma sebaceum is easily recognised. Incomplete forms, however, can provide considerable diagnostic difficulties. Angiographically, appearances are found which cannot be differentiated with certainty from those of malignant tumours. Malignant tumours are very rare in this condition. Nephrectomy can be avoided if the diagnosis is made at an early stage. Two female patients are reported, in one of whom the diagnosis was made by renal angiography. Despite the presence of large tumours in both kidneys, these organs could be preserved by surgery. In the second patient there were also bilateral renal hamartomas, but surgery was not carried out. Both cases showed typical changes in the fingers and toes as well as intracerebral calcification, and in one the lungs were affected.
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PMID:[The place of radiology in tuberous sclerosis (author's transl)]. 15 82

Content of phenylalanine and tyrosine was increased in blood serum in mongolism. When 4 patients with mongolism and 10 healthy persons were loaded with 1-phenylalanine, content of the amino acid in blood serum of patients exceeded 1.5--2-fold that found in healthy persons within 4 and 6 hrs after the treatment. The hydroxylation rate of phenylalanine was lower in mongolism as compared to normal state; it corresponded to the rate of phenylalanine hydroxylation in atypical homo- and heterozygote patients bearing "phenylketonuria" gene and in patients with viral hepatitis. Concentration of tyrosine was distinctly higher in the impaired patients within 2--6 hrs after the loading as compared with the healthy persons. But content of tyrosine was increased only slightly in patients with mongolism during the loading and excretion of homogentisinic acid with urine was decreased. These data suggest that activity of phenylalanine hydroxylase system is impaired in liver tissue in mongolism. Excretion of phenylpyruvic acid with urine was not observed in the patients and healthy persons both before and during the amino acid loading. The data obtained suggest that impairment of phenylalanine and tyrosine turnover in mongolism appears to be one of the factors responsible for disturbance of neurotransmitter synthesis and to be related to development of mental retardation.
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PMID:[Disorders of phenylalanine and tyrosine metabolism in Down's syndrome]. 15 71

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.
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PMID:Disease pattern among 942 mentally retarded persons in a Danish county. 15 88

The prevalence, in children aged under 15, of severe impairments of social interaction, language abnormalities, and repetitive stereotyped behaviors was investigated in an area of London. A "socially impaired" group (more than half of whom were severely retarded) and a comparison group of "sociable severely mentally retarded" children were identified. Mutism or echolalia, and repetitive stereotyped behaviors were found in almost all the socially impaired children, but to a less marked extent in a minority of the sociable severely retarded. Certain organic conditions were found more often in the socially impaired group. A subgroup with a history of Kanner's early childhood autism could be identified reliably but shared many abnormalities with other socially impaired children. The relationships between mental retardation, typical autism, and other conditions involving social impairment were discussed, and a system of classification based on quality of social interaction was considered.
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PMID:Severe impairments of social interaction and associated abnormalities in children: epidemiology and classification. 15 84

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.
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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.
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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.
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PMID:Complications related to the administration of general anesthesia in 600 developmentally disabled dental patients. 15 47


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