Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026827 (hypotonia)
 5,860 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Five cases with different abnormalities of chromosome 18 are described: one case with trisomy 18, two cases with ring 18, one case with partial trisomy 18q and one case with a mosaic 18p-/iso 18q. The karyotypes of the parents were normal. Cytogenetic analysis was performed on PHA stimulated blood lymphocytes. GTG, QFQ, MTX banding techniques were used. Karyotype-phenotype correlations are made. All patients present mental retardation, hypotonia and facial dismorphisms. The different degree of mental retardation and the clinical signs are in relation to the different size of deletions or trisomies of the short or long arm of chromosome 18. In the case with mosaicism 18p-/iso18q the phenotype is determined from the chromosomal abnormality more frequent in the cells (18p-).
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PMID:[Correlations between karyotype and phenotype in structural and numerical abnormalities of chromosome 18]. 146 1

OPHN1 mutations cause a syndromic form of mental retardation (MR) characterized by cerebellar hypoplasia, early hypotonia, motor and speech delay, with occasional seizures and strabismus. Here we report on a familial chromosome duplication spanning about 800 Kb of Xq12q13.1, associated with MR and a distinctive phenotype in the affected male, but not in his heterozygous mother. The parents were healthy and non-consanguineous with a history of three pregnancies. The first resulted in the birth of a boy with MR, motor impairment and seizures. The second pregnancy was terminated because of trisomy 18. At the time of the third, the first affected boy was analyzed by array-CGH, which revealed a 800 Kb duplication at Xq12q13.1, encompassing three genes, including OPHN1. This mutation was inherited from his healthy mother and was not present in any of the three maternal brothers. To our knowledge this is the first report of a clinical phenotype associated with duplication of Xq12q13.
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PMID:Association of syndromic mental retardation with an Xq12q13.1 duplication encompassing the oligophrenin 1 gene. 1851 29

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

This case report presents a coincidence of trisomy 18 and balanced Robertsonian translocation (13;14). Aneuploidy was suspected based on anomalies detected in ultrasound scan and confirmed with karyotype. In a 31 years-old healthy woman with a history of one miscarriage, second trimester ultrasound scan reported IUGR (<3rd percentile) with normal amniotic fluid, bilateral choroid plexus cysts, suspicious agenesis of corpus callosum and clenched hands. Amniocentesis was performed and karyotype was 46xx,der(13;14) (q10;q10),+18. Maternal karyotype was 45xx,der(13;14)(q10;q10). Pregnancy was continued due to legal limitation for termination after 20 weeks gestation. Delivery was done at 36 weeks gestation. A female newborn was borned and a physical feature was hypotonia, small mouth, prominent occiput, low-set and posteriorly rotated ears, clenched hands with overlapping fingers and rocker bottom feet. Ultrasound scan and echocardiography detected agenesis of corpus callosum and VSD, ASD, PDA and cardiomegaly. These features are typical of trisomy 18. Balanced Robertsonian translocation usually has no phenotypic expression. Genetic counseling and prenatal diagnosis for future pregnancy was recommended.
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PMID:Coincidence of trisomy 18 and robertsonian (13; 14). 2311 16

Circulating cell-free DNA, having no procedural risk of miscarriage, is the most suitable sample for a noninvasive prenatal testing (NIPT). Here we report on a boy, who came to our attention for hypotonia and psychomotor delay when he was 16 months old. During the pregnancy his mother performed a NIPT that resulted compatible with the presence of trisomy 18. A confirmatory invasive procedure has been proposed, but not performed, because the family preferred to follow a conservative line. A series of ultrasound excluded the presence of any major malformations. Genetic tests, performed after birth, revealed the presence of a tetrasomy 18p with an extra isochromosome 18p. Our report wants to underline the importance of an invasive procedure and consequent cytogenetic analysis in case of NIPT results indicating autosomal trisomies because under it may hide the presence of other structural chromosomal anomalies. These conditions are normally not visible at prenatal ultrasound or using combined test (CT) and the only identifiable not invasive sign could be the results of high risk at NIPT.
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PMID:Tetrasomy 18p: The challenges of noninvasive prenatal testing and combined test. 3054 32