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)

Karyotyping was done in 100 children suspected of having chromosomal abnormalities of genetically uncertain syndromes, multiple congenital anomalies, short stature, dysmorphic features, unclassified mental retardation, and Down syndrome. A total of 56 patients had an abnormal karyotype: ring chromosome of 13 was seen in 1 patient (1.78%), and trisomy 21 was seen in 29 patients (51.78%) who were diagnosed as Down syndrome patients. Among them, 9 were male patients (31.03%) (47,XY+21) and 18 were female patients (47,XX+21) (62.06%); 2 patients showed 47,XY+21/46,XY (mosaicism) (6.89%). Chromosomal rearrangements involving chromosome numbers 13, 14, and 21 were seen in three patients. Among them, one patient had t(13;21) [45,XX,t(13;21)] and two patients had 45,XY,t(14;21). Trisomy 22 was seen in three patients (5.3%), marker chromosome was seen in two patients (3.57%), 46,XY,16qh variant was seen in one patient (1.78%), 46,XX,der(2) was seen in one patient (1.78%), 46,XX,14ps+ was seen in two patients (3.57%), and 46,XY,r(18) was seen in three patients (5.37%). Apart from this, 11 patients (19.64%) had sex chromosome aberrations: 45,XO was seen in 3 patients (27.7%), 4 patients were mosaic for Turner syndrome (45,XO/46,XX) (36.36%), and 4 patients had 46,Xi(Xp) (36.36%), and the remaining 44 patients had normal karyotypes. All of them showed phenotypic-cytogenetic heterogeneity. These findings suggest that cytogenetic analysis is useful in the investigation of children with genetic disorders of unknown origin to confirm clinical diagnosis and to allow for proper genetic counseling.
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PMID:Increasing role of cytogenetics in pediatric practice. 2038 56

We report on the case of a patient with mosaic trisomy 22, who was diagnosed prenatally by amniocentesis during the 16(th) week of pregnancy. In the foetus, three trisomic clones were found out of the nine that were analyzed (the other six clones had a 46,XY karyotype). Cytogenetic analysis of cord blood during the 20(th) week of pregnancy showed a normal male karyotype; however, a placental biopsy that was performed at the same time showed 100% and 95% trisomic cells in the chromosomal analysis of direct and long-term cultures, respectively. A follow-up ultrasonographic examination excluded major congenital malformations and the abdominal and cranial circumferences were normal until the 24(th) week of pregnancy. At this point, a deflection of the growth curve occurred and the values were persistently below the 3(rd) centile until birth. After birth, karyotypic and fluorescent in situ hybridisation analyses performed on the fibroblasts of the neonate showed that 3-4% of the cell lines were trisomic, and studies using microsatellite markers showed normal allelic segregation, which excluded uniparental disomy. The period of postnatal follow-up was characterised by a significant growth deficit (height and head circumference were less than the 3(rd) centile) and by mental retardation. The present case is compatible with other earlier reports that showed that the levels of trisomy 22 are tissue-specific and are of little help in establishing the prognosis of the chromosomal abnormality.
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PMID:Prenatal diagnosis and postnatal follow-up of a child with mosaic trisomy 22 with several levels of mosaicism in different tissues. 2072 87


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