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)

Second trimester ultrasound-guided fetal blood sampling and placental biopsy were performed on 10 pregnancies at risk for fra(X)-linked mental retardation (Martin-Bell syndrome). Three cases were diagnosed as affected after cytogenetic analysis of fetal blood and placental cultures. The fra(X)(q27.3) and common fragile sites were shown to be expressed at a lower level in placenta than in fetal blood. Induction methods included methotrexate, 5-fluoro-2-deoxyuridine, and excess thymidine. Excess thymidine may give the best expression of fra(X)(q27.3). Enhancement of fra(X)(q27.3) expression was not shown with caffeine or 5-methoxybenzamide.
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PMID:Prenatal diagnosis of fragile X syndrome by placental (chorionic villi) biopsy culture. 317 58

The fragile site at Xq27, associated with a common form of X-linked mental retardation (XLMR), is expressed in a variable proportion of the peripheral lymphocytes of affected males when the cells are cultured under thymidylate stress (Td stress) produced by folate or thymidylate deprivation. Some clinically normal males--transmitting males--are known to carry and transmit the fragile X mutation and yet show no cytogenetic expression in lymphocytes. Normal males with no family history of X-linked mental retardation express the site only rarely. When the fragile X chromosome from affected males is isolated in a rodent genetic background by somatic cell hybridization, the level of expression is similar to that seen in lymphocytes under Td stress. Here we show that X chromosomes from two transmitting males and two normal control males, all of which were fragile X negative in lymphocytes or lymphoblasts, could be made to express the fragile site in hybrids, although at levels that were below those seen in hybrids from affected males. Furthermore, transmitting males could be differentiated from normal males by their significantly higher expression rates when hybrids were exposed to caffeine before cytogenetic harvest. One male chimpanzee also showed low level expression in hybrid cells. These data suggest that the hybrid system lowers the threshold for fragile X expression, a fragile site at Xq27 may be present on all human and chimpanzee X chromosomes and constitutes a previously unrecognized common fragile site and the hybrid system with caffeine post-treatment can distinguish between the common Xq27 fragile site of control males, the occult mutant fragile site of a transmitting male, and the fully expressed fragile site of an affected male with XLMR. Thus the mutation producing XLMR may represent a multi-step alteration of a naturally occurring DNA sequence producing a continuum of cytogenetic expression and a threshold for clinical manifestation.
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PMID:Implications of fragile X expression in normal males for the nature of the mutation. 378 81

Trisomy 18 is frequently associated with neurologic abnormalities, including hypotonia in infancy, mental retardation, central apnea, and epilepsy. Although central apnea and epilepsy are common complications in children with trisomy 18, epileptic apnea in these children was not previously reported. We describe an infant with trisomy 18 who developed epileptic apnea. Her apneic episodes began at age 10 months, occurring in clusters over several days each month. According to ictal electroencephalogram, interictal [(11)C] flumazenil-positron emission tomography, and [(18)F] fluorodeoxyglucose-positron emission tomography, the apneic episodes represented complex partial seizures (autonomic seizures), probably originating in the left frontotemporal area, probably related to cortical microdysgenesis. The condition was successfully treated with zonisamide. In infants with trisomy 18, differentiation of epileptic apnea from central apnea is crucial, because medications used to treat central apnea, including caffeine and theophylline, can be harmful to children with epileptic apnea.
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PMID:Epileptic apnea in a trisomy 18 infant. 2000 66

A 31 years old man with history of familial psychiatric disorder was investigated. Chromosomal analysis in peripheral lymphocyte blood culture showed normal karyotype with 46, XY chromosomal complement. However, the cells treated with 5-Fluoro-deoxy-uridine (FUdR) and Caffeine showed fragile Xq-27 (4.0%) and nonspecific autosomal breakages (42.0%). The present case suggests a probable association between chromosomal fragility and non-mental retardation psychopathology. Further cytogenetic studies in cases with familial psychiatric disorders will enable us with a better understanding of the pathogenesis and further help in counselling the families.
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PMID:FRAGILE Xq-27 ASSOCIATED WITH SCHIZOPHRENIA AND FAMILIAL PSYCHOSIS AN A MALE. 2192 11