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

Six cases of translocation trisomy for the distal half of the short arm of a number 9 chromosome and four asymptomatic balanced translocation carriers are presented in a three-generation pedigree. The clinical features are remarkably similar to those recently recognized and increasingly reported in full short arm (9p) trisomy and should be considered a modification of the same syndrome. In addition to non-specific mental retardation and short stature, there is, in common, a characteristic facies, including down-turned corners of the mouth, a slightly bulbous nose, moderately large ears, suggestively wide-set eyes with an antimongoloid slant, dysplasia and hypolasis of the nails, clindactyly of the 5th fingers, and abnormal dermatoglyphs. It appears that the 'trisomy 9p syndrome' in its variant forms, including trisomies for more or less than just the short (p) arm, is one of the most common clinical autosome anomalies in humans, exceeded only by trisomy 21 (Down's syndrome) and possibly trisomies of chromosomes 13 and 18.
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PMID:Familial 'partial 9p' trisomy: six cases and four carriers in three generations. 5 62

The prevalence of hepatitis B surface antigen (HBsAg) in 155 patients with Down's syndrome (DS) and 209 with other types of mental retardation (OMR) at Huronia Regional Centre, Orillia, Ontario was 34.8 and 5.3%, respectively. There was no significant difference in prevalence between males and females in either group of patients. In 75 matched pairs (DS-OMR) the HBsAg prevalence was 45% in DS and 8.3% in OMR males; in females 40% of those with DS were HBsAg-positive, whereas all the OMR residents were negative. The prevalence of HBsAg in both DS and OMR groups was higher in those admitted in early childhood and in those who had resided in the institution for more than 10 years. In all 54 HBsAg-positive DS patients the antigen subtype was ad. Among the 11 HBsAg-positive OMR patients the subtype was ad in 10 cases and ay in 1.
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PMID:Hepatitis B surface antigen and its subtypes in an institution for the mentally retarded. 12 13

Computer analyses of the electroencephalograms of normal children, and children with Down's syndrome who were mentally retarded, revealed differences in the distribution of amplitude between the two groups. Normal children, in the early postnatal period, generate EEG's which have a non-Gaussian distribution of amplitude that becomes increasingly Gaussian before one year of age and remains so throughout subsequent development. Conversely, the EEG's of children with Down's syndrome exhibit highly non-Gaussian properties at all ages studied. The EEG's of two mentally retarded autistic children did not show this property, so it is not merely a concomitant of mental retardation. The first-order Gaussian distribution may reflect the degree of inteneuronal coupling; since an increased number of connections on any neuron implies decreased functional dependence of that neuron on any other particular single neuron, the present evidence, which indicates stronger interneuronal coupling in mongoloids, suggests that Down's syndrome may be associated with incomplete postnatal development of interconnections between cortical neurons.
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PMID:Non-Gaussian behavior of the EEG in Down's syndrome suggests decreased neuronal connections. 12 3

To date, a total of eight cases of the Turner-mongolism polysyndrome have been recognized. The clinical manifestations included retarded growth (resulting in a small and infantile appearance), with shield-like chest, poorly developed breasts, absent body hair, brachycephaly, short neck with foldings and low hairline, oblique eyes with epicanthal folds, squat nose, scrotal or normal tongue, abnormal hard palate (high or cleft), short hands and feet, frequent cubitis valgus, normal clitoris (may be either hypoplastic or peniform), mental retardation, and the XO/G+ karyotype, mosaic for XO in most instances. At this time, a single cause for all cases of the double aneuploidy is not known.
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PMID:Turner-mongolism polysyndrome. Review of the first eight known cases. 12 53

Hepatitis-Associated (Australia) Antigen (HAA) was detected in 13 (5.8%) of 223 patients with Down's syndrome and in 14 (3.7%) of 378 patients with other forms of mental retardation. The frequency of HAA was 2.4 per cent in 127 noninstitutionalized patients with Down's syndrome, and 10.4 per cent in 96 institutionalized patients. The frequency of HAA with Down's syndrome was lower on the average in Japan than in the United States or Germany. HAA was detected in one (1.3%) of 78 mothers of infants with Down's syndrome. Our study suggests that maternal exposure to HAA, as reflected by the presence of either HAA or anti-HAA, was not associated with the subsequent birth of an infant with Down's syndrome.
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PMID:Hepatitis-associated (Australia) antigen and Down's syndrome. 12 83

Data obtained concerning Hepatitis B as a possible couse of Down's syndrome, neonatal hepatitis, and the occurrence of Hepatitis A and B in institutionalized Down's syndrome and matched non-Down's syndrome retarded patients was summarized. The results of our studies indicated that Hepatitis B infection during pregnancy was not related to the genetic changes associated with Down's syndrome. It was further indicated that in institutionalized patients the incidence of Hepatitis B infection in both Down's syndrome and other mentally retarded patients was similar. Within the institition we studied, the incidence of Hepatitis B varied among wards. This ward variation seemed to be related to age at time of institutionalization and degree of mental retardation. Those patients with most retardation and those institutionalized at an early age were placed on wards with highest incidence of Hepatitis B antigenemia.
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PMID:Hepatitis and Down's syndrome. 12 5

698 children below age sixteen years with severe mental handicap (below IQ50) who were admitted to hospital between 1956 and 1959 were surveyed for genetic prognosis. They were divided into 23.7% ascribed primarily to environmental factors, 50.9% unclassified aetiologically, 16.2% of Down's syndrome, 5.3% other genetic syndromes and 3.9% with congenital hydrocephalus. The incidence of a similar degree of mental retardation among the sibs of 660 whose families were traced, was 1.1% in the "environmental" group; 4.7% for the unclassified; 1.7% for Down's syndrome, 11.5% for other genetic syndromes and 4.3% for hydrocephalus with spina bifida. There were no affected sibs of the uncomplicated cases of congenital hydrocephalus. This survey underlines the fact that a high proportion of cases of mental handicap remain without aetiological diagnosis. It emphasises the value of such a diagnosis for genetic counselling. Advice given depends on the circumstances of the particular case which requires a detailed social history and sympathetic rapport by members of the team as well as appropriate clinical expertise (Kirman, 1971, 1972). When families with similarly affected new relative or previous severely mentally handicapped sibs are set aside, the recurrent risk for unclassified cases is reduced to three per cent.
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PMID:Genetic prognosis in severe mental handicap. 12 70

The neuronal organization of the motor cortex of a 19-month old child with Down's syndrome (mongolism) has been studied with the rapid Golgi method. This congenital syndrome, also known as 21 Trisomy is caused by a chromosomal abnormality consisting of the presence of an extra chromosome in the group 21. Various structural abnormalities have been found in the dendritic spines (postsynaptic structures) of the pyramidal neurons of the motor cortex of this child. The axo-spinous synapses of these neurons are considered to be altered by these spine abnormalities. In addition, a peculiar form of intrinsic vacuolar change affecting the dendrites and scattered neuronal fragmentation and necrosis have also been found. At least three different types of abnormality involving the spines--(the unusually long spine, the very short spine and a reduction in the number of spines)--are recognized among the pyramidal cells of the motor cortex. It is postulated herein: that a basic anomaly, possibly related to the genetic disorder affects primarily some cortical neurons which undergo progressive degenerative changes terminating in cell fragmentation and death. The different spine abnormalities are considered to represent various developmental stages of the common genetic anomaly. These changes might be structural correlates of the motor incoordination and mental retardation which are characteristic of this genetic disorder, but, final conclusions should await the investigation of other cases with this or similar methods capable of demonstrating the normal as well as the abnormal structural organization of the human cerebral cortex.
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PMID:Pyramidal cell abnormalities in the motor cortex of a child with Down's syndrome. A Golgi study. 13 10

An abnormal chromosome 21 is reported in a child with a phenotype strongly reminiscent of trisomy 21 syndrome. It is shown to result from duplication of the segment 21q21 leads to 21q22.2. Comparison of the phenotype with that of other partial and total trisomics shows that the characteristic features of the trisomy 21 syndrome (mongolism), the mental retardation in particular - is due to trisomy 21q22.2 and perhaps 21q22.2.
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PMID:[Partial trisomy 21 (21q21 - 21q22.2)]. 13 30

A cytogenetic survey of the complete population of mentally subnormal in the North-East of Scotland has been undertaken. A register for the mentally subnormal within the region already existed, and all persons recorded, whether they resided at home or in subnormality hospitals or other institutional care, were included. The total number recorded was 3020 and of these 2770 were examined cytologically. In all 297 (10.7%) were shown to have a chromosomal abnormality, and of these Down's syndrome accounted for 250 (9%). Within this category was an unexpected excess of males. Deletions and supernumeraries comprised the remaining autosomal anomalies. Increased numbers of sex chromosome abnormalities among high grade mentally subnormal individuals were confirmed for both sexes. The survey has shown that abnormal chromosome complements contribute significantly to the causation of mental retardation, and has also provided estimates which cannot be obtained from hospital surveys alone.
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PMID:Chromosome survey of total population of mentally subnormal in North-East of Scotland. 13 60


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