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

We report on the incidence of seizures in 113 patients with Down Syndrome (DS), 43 coming from the OASI Institute for Research on Mental Retardation and Brain Aging, Troina, and 70 from the outpatient clinic of the Department of Pediatrics, University of Catania. We obtained the following results: 15 (13.2%) patients had seizures; 6 (5.3%) febrile seizures (FS) and 9 (7.9%) afebrile seizures (aFS). Among the latter group 2 patients had generalized tonic-clonic seizures, 3 partial complex seizures, and 4 infantile spasms. The seizures appeared early in life. Only 2 adult patients had seizures. These results suggest that patients with DS show a higher incidence of FS and of aFS than non-DS individuals. Seizures in DS may be an epiphenomenon of the neurological abnormalities, both anatomical and functional, usually observed in these patients.
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PMID:Seizures in patients with trisomy 21. 214 64

Review of the clinical cytogenetic literature provides compelling evidence for a specific relationship between imbalance of particular chromosomes or chromosomal regions and the appearance of defined patterns of phenotypic abnormalities. In many instances, detailed phenotypic mapping has made it possible to assign portions of a phenotype to relatively small chromosome segments, which are sometimes referred to as "critical regions." However, since these regions are usually defined by a subset of the phenotypic manifestations of an aneuploidy syndrome--generally those anomalies that are regarded as most characteristic or readily observable--it is important not to fall into the trap of thinking that it is imbalance of only these regions that has deleterious effects on development and function. Thus, in Down syndrome, the presence of an extra copy of the proximal part of 21q22.3 appears to result in the typical physical phenotype--as defined principally in terms of the characteristic facial and hand anomalies and congenital heart defect--in addition to mental retardation. But, duplication of proximal 21q also affects mental development, and the regions responsible for many other aspects of the Down syndrome phenotype, including Alzheimer disease, have not been defined at all. Therefore, it remains likely that loci present on many parts of the long arm of chromosome 21 play a role in the development of the overall phenotype of Down syndrome. The immediate effect at the molecular level of an aneuploidy-caused alteration in gene dose appears to be a non-compensated commensurate change in the production of gene products.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The consequences of chromosome imbalance. 214 68

The philosophy of community care means that responsibility for the care of children with Down syndrome (DS) remains still more firmly with the families. Demographic changes have made the typical DS family of the 1970s and 1980s differ in structure, size, and status from that typical of earlier decades. The findings of a population study of DS children and their families, matched with children with a similar degree of mental retardation, and of a longitudinal study of DS children born 1970-1972, are discussed in relation to a series of similar studies. From these results it is possible to identify vulnerable families for appropriate help.
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PMID:Down syndrome children and their families. 214 69

Down syndrome (DS) is a major cause of mental retardation and heart disease. Although it is usually caused by the presence of an extra chromosome 21, a subset of the diagnostic features may be caused by the presence of only band q22. Molecular and cytogenetic analysis of a family with 4 DS members has significantly narrowed the chromosomal region responsible for the DS phenotype: congenital heart disease, facial features, and possibly dermatoglyphics. Using high-resolution chromosome banding and in situ hybridization, we found the DS phenotype in the family is caused by a duplication of chromosome 21 material including a region of distal band q22.1 below the limit of cytogenetic resolution, in addition to bands q22.2-q22.3. By quantitative Southern blot analyses of DS members of the family, all random DNA sequences and expressed genes mapping in band q22.1 and proximal are found not to be duplicated. These include cDNA probes for the genes for superoxide dismutase (SOD1) mapping in 21q22.1 and for the amyloid precursor protein (APP) mapping in 21q21.05; D21S46 in 21q11.2-21.05; and D21S47 and SF57 in 21q22.1-q22.3. With one exception, DNA sequences mapping in band q22.3 are duplicated (D21S39, D21SD42, and D21S43). This analysis has now been extended to show that D21S17, previously mapped to band 21q22.3, is not duplicated. In conclusion, the genes SOD1 and APP have been excluded from a necessary role in generating the classical DS features, and the proximal border of the chromosomal region causing DS has been defined.
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PMID:Down syndrome: toward a molecular definition of the phenotype. 214 83

The diffusion of hepatitis B virus was investigated in an open institution for mentally retarded patients, where 24 patients with Down's syndrome (DS) and 94 with other types of mental retardation (OMR) were being cared for. The immunogenic response to a recombinant vaccine intramuscularly injected to the deltoid muscle at a dosage of 20 mcg in the months 0, 1 and 6 was also evaluated. Seropositivity for some hepatitis B serum marker was found in 19.4% of patients (12.5% of those with DS and 21.2% of those with OMR). HBsAg was found in 8.3% of patients with DS and in 4.2% of those with OMR. The seroconversion to antiHBs induced by the vaccine 8 months after the first dose was found in 72.3% of DS and in 100% of OMR. The poor immunogenic response in DS was attributed to age, as in patients younger than 20 years it was 91.6% while in those over that age it was only 33.3%. It was concluded that in open institutions for mentally retarded patients there is a risk of hepatitis B infection, also shown in closed institutions, and that recombinant hepatitis B vaccine is highly immunogenic in this population, although it has been found that in patients with DS the age has a very marked negative influence on the response to the vaccine.
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PMID:[Hepatitis B at an open institution for the mentally retarded. Immunogenic effect of a recombinant anti-hepatitis-B vaccine]. 215 Dec 50

Fragile X (fra[X]) syndrome is a newly discovered, but relatively common, genetic disorder with an estimated frequency of 1:1000. Several ocular dysfunctions may be associated with this syndrome, but there are few articles that fully report on these. A review of this genetic disorder is provided, as well as a discussion of a case review of a family with three siblings with fragile X syndrome. Since this disorder is the most common familial cause of mental retardation, is second only to Down's syndrome as a genetic cause for mental retardation, and may play a significant role in learning disabilities, the eye care practitioner should be aware of its importance.
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PMID:Ocular anomalies in fragile X syndrome. 218 24

We examined the brains of 385 mentally retarded adults aged 23-90 years without Down's syndrome (DS), metabolic disorder, or hydrocephalus to extend our knowledge about the occurrence of Alzheimer-type neuropathology in this population. Relevant measures of neuropathology also were related to selected information available from clinical records. The presence of one or more neurofibrillary tangles (NFT) and/or neuritic plaques (NP) was observed in 63.4% of all cases and varied with age. The prevalence of positive cases was higher when mental retardation was due to head trauma, congenital malformation, or familial factors and when a history of seizures was reported. Comprehensive morphometric analyses of neocortical, hippocampal and parahippocampal areas indicated that recommended age-specific quantitative criteria for the diagnosis of Alzheimer disease [Khachaturian ZS (1985) Arch Neurol 42:1097-1105] were met in 9.5% of cases less than 50 years of age, 54.2% between 50 and 65, 70% between 66 and 75, and 87% of the cases greater than 75 years of age. However, a limited immunohistochemical study revealed that in most cases the NP did not have a neuritic component containing paired helical filaments and in this respect most of the plaques observed in this population may differ from those most strongly associated with Alzheimer disease. In addition, substantial numbers of NFT were seen in frontal cortex, contrasting with results reported in the literature for nonretarded populations. The number of NP per mm2 consistently increased with age for all areas examined, while the relationship between NFT density and age varied across areas, and was clearly not monotonic.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Alzheimer neuropathology in non-Down's syndrome mentally retarded adults. 223 48

The present study describes the cytogenetic findings in cases suspected with chromosomal abnormalities, in cases of mental retardation, multiple congenital malformations, clinical features of Down's syndrome, Klinefelter's syndrome, Turner's syndrome, ambiguous sex, sterility, amenorrhea and history of repeated spontaneous abortions in couples. Cytogenetic studies were done in 144 of the total 205 cases. In all, 57 (39.58%) were shown to have chromosomal abnormality and of these, 34 cases (25.7%) were Down's syndrome. Sex chromosome abnormality was found in 19 cases (13.2%). The results confirm the significant contribution of chromosomal abnormalities in the genesis of mental retardation, and abnormal sexual development.
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PMID:Cytogenetic studies in a population suspected to have chromosomal abnormalities. 224 22

The clinical significance of low numbers of aneuploid cells in routine cytogenetic studies of cultured lymphocytes is not always clear. We compared the frequencies of chromosome loss and gain among five groups of subjects whose karyotypes were otherwise normal; these groups were (1) subjects studied because of multiple miscarriages, (2) parents of live borns with autosomal trisomy, (3) subjects studied because they had a relative with Down syndrome, (4) an age-matched control group of phenotypically normal adults studied for other reasons (e.g., parent of a dysmorphic child or member of a translocation family), and (5) other mostly younger and phenotypically abnormal subjects who could not be assigned to the first four groups (e.g., individuals with multiple congenital anomalies or mental retardation). No significant age, sex, or group effects were observed for autosomal loss (hypodiploidy) or gain (hyperdiploidy). Autosomal loss was inversely correlated with relative chromosome length, but autosomal gain was not. Sex-chromosome gain was significantly more frequent in females than in males, but sex-chromosome loss was not significantly different between the sexes. Significant age effects were observed for both gain and loss of sex chromosomes. When age and sex were accounted for, the frequencies of sex-chromosome loss and gain were not significantly different among the five clinical groups. In general, low numbers of aneuploid cells are not clinically important when observed in blood chromosome preparations of subjects studied because of multiple miscarriages or a family history of autosomal trisomy.
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PMID:The frequency of aneuploidy in cultured lymphocytes is correlated with age and gender but not with reproductive history. 233 3

In a study of special education programs in five urban school systems, parent interview data for 1726 children revealed how early the children's problems were identified and how the medical system was involved in the diagnosis. Problems included speech impairment, learning disabilities, emotional disturbance, mental retardation, sensory disorders, and physical and health disabilities. Overall, 4.5% of the children's problems were identified at birth, and only 28.7% before the age of 5 years. Variation in age at identification depended on the condition: 1 year for Down syndrome and cerebral palsy versus a 6-year range for mental retardation. Although physicians were most likely to identify the less common, more severe handicaps, they also identified from 15% to 25% of learning disabilities, speech impairments, emotional disorders, hyperactivity, and "other" development problems. The type, severity, and complexity of the condition were significant predictors of physician identification. No racial, socioeconomic, or site biases were associated with whether a physician was first to identify. Age at identification was predicted by the complexity of the problem, the association with other health and developmental concerns, socioeconomic indicators, and whether a physician was involved in the diagnosis. In the absence of clear assumption of responsibility for early identification, much terrain remains uncharted by medical practitioners and the schools. A better systematic sharing of responsibility for the early identification of developmentally disabling conditions is needed.
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PMID:Early identification of children's special needs: a study in five metropolitan communities. 244 88


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