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

A four-generation Swedish family with a new type of X-linked mental retardation syndrome was recently reported by Gustavson et al. The complex syndrome includes microcephaly, severe mental retardation, optical atrophy with decreased vision or blindness, severe hearing defect, characteristic facial features, spasticity, seizures, and restricted joint motility. The patients die during infancy or early in childhood. Twenty-one family members, including two affected males, were available for study. Linkage analysis was conducted in the family by using 11 RFLP markers and 10 VNTR markers spread along the X chromosome. A hypervariable short tandem repeat of DXS294 at Xq26 showed a peak two-point lod score of 3.35 at zero recombination fraction. Calculations using the same markers revealed a multipoint peak lod score of 3.65 at DXS294. Crossover events with the centromeric marker DXS424 and the telomeric marker DXS297 delimit a probable region for the gene localization. It is noteworthy that hte disease loci of two other syndromes with overlapping clinical manifestations recently were shown by Turner et al. and Pettigrew et al. to be linked to markers at Xq26.
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PMID:Linkage mapping of a severe X-linked mental retardation syndrome. 850 40

The Norrie disease and MAO genes are tandemly arranged in the p11.4-p11.3 region of the human X chromosome in the order tel-MAOA-MAOB-NDP-cent. This relationship is conserved in the mouse in the order tel-MAOB-MAOA-NDP-cent. The MAO genes appear to have arisen by tandem duplication of an ancestral MAO gene, but their positional relationship to NDP appears to be random. Distinctive X-linked syndromes have been described for mutations in the MAOA and NDP genes, and in addition, individuals have been identified with contiguous gene syndromes due to chromosomal deletions which encompass two or three of these genes. Loss of function of the NDP gene causes a syndrome of congenital blindness and progressive hearing loss, sometimes accompanied by signs of CNS dysfunction, including variable mental retardation and psychiatric symptoms. Other mutations in the NDP gene have been found to underlie another X-linked eye disease, exudative vitreo-retinopathy. An MAOA deficiency state has been described in one family to date, with features of altered amine and amine metabolite levels, low normal intelligence, apparent difficulty in impulse control and cardiovascular difficulty in affected males. A contiguous gene syndrome in which all three genes are lacking, as well as other as yet unidentified flanking genes, results in severe mental retardation, small stature, seizures and congenital blindness, as well as altered amine and amine metabolites. Issues that remain to be resolved are the function of the NDP gene product, the frequency and phenotype of the MAOA deficiency state, and the possible occurrence and phenotype of an MAOB deficiency state.
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PMID:Norrie disease and MAO genes: nearest neighbors. 854 72

The incidence of IBEM in Thailand is yet unknown, however, by estimation it is generally accepted to be 1 in 5,000. From a recent survey in 7 medical schools from different parts of the country and a largest pediatric hospital in Bangkok, we found numerous cases of IBEM nationwide. These are amino acids disorders, carbohydrate disorders, urea cycle defects, peroxisomal, lysosomal storage disorders and many others. Since Thais are quite homogeneous in their genetic make-up; it is, therefore, very likely that IBEM is much more prevalent than we realized. With the exception of thalassemias, IBEM is very common in Thailand and other countries in the Asia-Pacific region. It is a real burden, indeed, since the consequences of IBEM are very serious, eg permanent damage to the CNS causing mental retardation, epilepsy, blindness, deafness and shortened life-span of individuals. Newborn screening for IBEM has been initiated at Siriraj and Ramathibodi Hospital Medical Schools of Mahidol University in 1993. There is yet no national screening program, although a pilot program was launched in the North, Northeast and the South by the Ministry of Health in 1991. Main problems we are facing include: only a handful of clinicians and scientists with expertise in IBEM; no well-equipped laboratory facilities; lack of funding and well-organized plan.
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PMID:IBEM in Thailand. 862 86

Students with mental retardation and deafness or deaf-blindness often need some type of communication system to communicate effectively with communication partners during community-based vocational training. However, students may need specific training to learn how to initiate requests for items or assistance, a skill identified as critical for job success. Students were taught to initiate requests using dual communication boards and gestures. Data were recorded on student performance using a multiple-baseline probe design in which data were collected during baseline, intervention, and generalization phases. Students were able to initiate requests with 80% to 100% accuracy with the communication system at vocational sites. Training students to initiate requests may need to be targeted when students are first learning a job, as this is when most naturally occurring opportunities exist.
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PMID:Initiating requests during community-based vocational training by students with mental retardation and sensory impairments. 874 51

Norrie disease is a severe X-linked recessive neurological disorder characterized by congenital blindness with progressive loss of hearing. Over half of Norrie patients also manifest different degrees of mental retardation. The gene for Norrie disease (NDP) has recently been cloned and characterized. With the human NDP cDNA, mouse genomic phage libraries were screened for the homolog of the gene. Comparison between mouse and human genomic DNA blots hybridized with the NDP cDNA, as well as analysis of phage clones, shows that the mouse NDP gene is 29 kb in size (28 kb for the human gene). The organization in the two species is very similar. Both have three exons with similar-sized introns and identical exon-intron boundaries between exon 2 and 3. The mouse open reading frame is 393 bp and, like the human coding sequence, is encoded in exons 2 and 3. The absence of six nucleotides in the second mouse exon results in the encoded protein being two amino acids smaller than its human counterpart. The overall homology between the human and mouse NDP protein is 95% and is particularly high (99%) in exon 3, consistent with the apparent functional importance of this region. Analysis of transcription initiation sites suggests the presence of multiple start sites associated with expression of the mouse NDP gene. Pedigree analysis of an interspecific mouse backcross localizes the mouse NDP gene close to Maoa in the conserved segment, which runs from CYBB to PFC in both human and mouse.
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PMID:Characterization and mapping of the mouse NDP (Norrie disease) locus (Ndp). 883 23

A group of Vancouver health professionals, including the authors, have studied the use of oral melatonin in the treatment of chronic sleep disorders in children with disabilities since the Fall of 1991. This review article is based on the first 100 patients, half of whom were visually impaired or blind. Children with neurological, neuropsychiatric, and developmental disabilities are predisposed to chronic sleep-wake cycle disturbances. Disorders such as blindness, deaf-blindness, mental retardation, autism, and central nervous system diseases, among others, diminish the ability of these individuals to perceive and interpret the multitude of cues for synchronizing their sleep with the environment. Melatonin, which benefitted slightly over 80% of our patients, appears to be a safe, inexpensive, and a very effective treatment of sleep-wake cycle disorders. The oral dose of fast release melatonin taken at bed-time ranged from 2.5 mg to 10 mg. Side effects or the development of tolerance have not been observed. Since the causes of sleep difficulties are extremely variable, not all children are candidates for treatment. For successful melatonin treatment, clinical experience is required, and the influences of other health problems and medications need to be considered. Further clinical and laboratory research in this field is imperative because melatonin treatment offers enormous health, emotional, social, and economic benefits to society, especially since multidisabled children with chronic sleep difficulties do not respond well to current therapeutic regimes.
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PMID:Use of melatonin in the treatment of paediatric sleep disorders. 898 17

A family with a newly detected X-linked syndrome including sensorineural deafness, mental retardation, dystonia and blindness was examined with full-field electroretinography in order to order to find out if the blindness was caused by a retinal degeneration. Six affected males and 2 obligate carriers showed no signs of retinal degeneration. One of 7 affected males had central areolar choroidal dystrophy confirmed by central scotomas in visual fields and an electroretinographic pattern consisting of an attenuated amplitude as well as a prolonged implicit time of the cone b-wave on stimulation with 30 Hz flickering white light.
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PMID:Full-field electroretinograms in a family with Mohr-Tranebjaerg syndrome. 901 58

Advances in perinatal and neonatal management have resulted in a significant increase in the survival of fragile extremely low birth weight (ELBW) infants > 1,000 g at birth. The evaluation and reporting of the outcome of these infants aids in assessing the efficacy of interventions, provides data to aid in policy decisions, and provides critical information for parents and primary care providers. Comprehensive assessment of multiple domains including neurologic/neurosensory, developmental-cognitive, visual perceptual, speech/language, motor, functional skills for daily living, and Kindergarten readiness permit a total view of the child within the context of the family. Survival of VLBW infants < 800 g has steadily improved from 0% (1943 to 1945) to 49% to 70% (1994 to 1995). Rates of cerebral palsy, mental retardation, blindness, and deafness have remained stable in the 1980s and 1990s. There is evidence, however, that the percent of functional limitations may be increasing. A requirement for Special Education Resources among VLBW infants remains high at 44% to 56%. As increasing numbers of infants at the limits of viability survive, the medical community must remain vigilant in its surveillance and advocate both humanistically and scientifically for comprehensive strategies that optimize long-term functional, academic, and family outcomes.
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PMID:Neuropsychological and functional outcomes of very low birth weight infants. 920 76

Eugenics, the attempt to improve the genetic quality of the human species by 'better breeding', developed as a worldwide movement between 1900 and 1940. It was particularly prominent in the United States, Britain and Germany, and in those countries was based on the then-new science of Mendelian genetics. Eugenicists developed research programs to determine the degree in which traits such as Huntington's chorea, blindness, deafness, mental retardation (feeblemindedness), intelligence, alcoholism, schizophrenia, manic depression, rebelliousness, nomadism, prostitution and feeble inhibition were genetically determined. Eugenicists were also active in the political arena, lobbying in the United States for immigration restriction and compulsory sterilization laws for those deemed genetically unfit; in Britain they lobbied for incarceration of genetically unfit and in Germany for sterilization and eventually euthanasia. In all these countries one of the major arguments was that of efficiency: that it was inefficient to allow genetic defects to be multiplied and then have to try and deal with the consequences of state care for the offspring. National socialists called genetically defective individuals 'useless eaters' and argued for sterilization or euthanasia on economic grounds. Similar arguments appeared in the United States and Britain as well. At the present time (1997) much research and publicity is being given to claims about a genetic basis for all the same behaviors (alcoholism, manic depression, etc.), again in an economic context--care for people with such diseases is costing too much. There is an important lesson to learn from the past: genetic arguments are put forward to mask the true--social and economic--causes of human behavioral defects.
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PMID:The social and economic origins of genetic determinism: a case history of the American Eugenics Movement, 1900-1940 and its lessons for today. 946 76

A population-based group of 27 children with total blindness due to retinopathy of prematurity (ROP), born in Sweden from 1980 to 1990, was examined. They constituted all but two of the total of 29 children with total blindness due to ROP known to the national register of visually impaired children when reviewed from 1980 to 1 January 1995. All children had a gestational age of less than 31 weeks and most had had a complicated perinatal period. The retinal disease was discovered late, most often after it had already progressed to bilateral retinal detachment. Repeated vitreoretinal surgery had been performed in most children, but postoperative visual function did not improve. Three-quarters of the group had major neurological impairment (mental retardation, cerebral palsy, or epilepsy) at age 4 to 14 years. There was an impression that extensive ophthalmological efforts delayed neurodevelopmental assessments and examinations as well as adequate habilitation.
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PMID:Children with blindness due to retinopathy of prematurity: a population-based study. Perinatal data, neurological and ophthalmological outcome. 956 50


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