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Query: UMLS:C0013080 (Down syndrome)
 14,180 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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 21q22. We now present evidence that significantly narrows the chromosomal region responsible for several of the phenotypic features of DS. We report a molecular and cytogenetic analysis of a three-generation family containing four individuals with clinical DS as manifested by the characteristic facial appearance, endocardial cushion defect, mental retardation, and probably dermatoglyphic changes. Autoradiograms of quantitative Southern blots of DNAs from two affected sisters, their carrier father, and a normal control were analyzed after hybridization with two to six unique DNA sequences regionally mapped on chromosome 21. These include cDNA probes for the genes for CuZn-superoxide dismutase (SOD1) mapping in 21q22.1 and for the amyloid precursor protein (APP) mapping in 21q11.2-21.05, in addition to six probes for single-copy sequences: D21S46 in 21q11.2-21.05, D21S47 and SF57 in 21q22.1-22.3, and D21S39, D21S42, and D21S43 in 21q22.3. All sequences located in 21q22.3 were present in three copies in the affected individuals, whereas those located proximal to this region were present in only two copies. In the carrier father, all DNA sequences were present in only two copies. Cytogenetic analysis of affected individuals employing R and G banding of prometaphase preparations combined with in situ hybridization revealed a translocation of the region from very distal 21q22.1 to 21qter to chromosome 4q. Except for a possible phenotypic contribution from the deletion of chromosome band 4q35, these data provide a molecular definition of the minimal region of chromosome 21 which, when duplicated, generates the facial features, heart defect, a component of the mental retardation, and probably several of the dermatoglyphic changes of DS. This region may include parts of bands 21q22.2 and 21q22.3, but it must exclude the genes S0D1 and APP and most of band 21q22.1, specifically the region defined by S0D1, SF57 and D21S47.
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PMID:Molecular definition of a region of chromosome 21 that causes features of the Down syndrome phenotype. 214 53

Down syndrome is the most common cause of mental retardation in children. The children need opportunities to become important members of their families. The preschool years are an excellent time for the children and family to learn about the condition and to establish behaviors that will optimize opportunities for the children to reach their maximum potential. Examples of nursing interventions based on developmental periods are provided.
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PMID:Down syndrome: nursing interventions newborn through preschool age years. 214 45

In trisomy 21, pathogenesis of mental retardation is still poorly understood although the knowledge of the genic content of chromosome 21 is steadily increasing. Short of discovering how to silence selectively one of the 3 chromosomes 21, no rational medication can be envisaged before pathogenesis has been unraveled, at least partially. A biochemical scheme of impairment of mental efficiency is presented. Secondarily, the possible deleterious effects of a given gene overdose are discussed. Cu/Zn SOD, cystathionine beta synthase, S 100 beta protein, phosphofructokinase, purine synthesis and adenosine pharmacology, thyroid disturbance, and elevated TSH with low rT3 as well as biopterine metabolism interferences are reviewed. It is observed that the metabolic paths controlled by these genes, although unrelated at first glance, are in fact tightly related by their effects, just as if synteny was in some way related to biochemical cooperation or mutually controlled regulation. Experiments in vitro have demonstrated a peculiar sensitivity of trisomic 21 lymphocytes to methotrexate. From this starting point, systematic research of special sensitivities has begun. Clinical observations and relevant statistical methods allow study of the speed of mental development under various medications. The interest of regulating thyroid metabolism, when needed, is exemplified. Reequilibration of monocarbon metabolism is discussed and the seemingly favourable effect of folinic acid medication in pseudo-Alzheimer complication is presented.
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PMID:Pathogenesis of mental deficiency in trisomy 21. 214 47

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


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