Prenatal diagnosis of a mosaic extra structurally abnormal chromosome by spectral karyotyping.
A de novo mosaic extra structurally abnormal chromosome (ESAC) was detected in 33 per cent of cultured amniotic fluid cells from a pregnant woman. Neither Q-banding nor fluorescence in situ hybridization (FISH) employing a DNA probe for nucleolar organizer region demonstrated the presence of satellites on the ESAC. Spectral karyotyping (SKY) was performed in this prenatal case and led to a quick and accurate determination of the ESAC as chromosome 14 in origin. The SKY finding was confirmed by conventional FISH analysis using a chromosome 14 specific painting probe. Subsequent hybridizations with a centromeric probe and a 14q subtelomeric probe were also performed to further characterize the ESAC. Absence of (TTAGGG)n sequence on the ESAC, determined postnatally, suggested it is a ring chromosome 14. Genetic counselling concerning these findings was provided to the parents who chose to continue the pregnancy. The male infant had no apparent abnormal phenotype at birth.
Ning
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Gene Care Medical Genetics Center and George Washington University, Washington, DC 20037, USA. obgypn@gwumc.edu
Laundon
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Schröck
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Buchanan
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Ried
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T
D000328:Adult; D002869:Chromosome Aberrations / Q000175:diagnosis*; D025063:Chromosome Disorders; D005260:Female; D005315:Fetal Diseases / Q000175:diagnosis* / Q000235:genetics; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007231:Infant, Newborn; D007621:Karyotyping / Q000379:methods*; D009030:Mosaicism / Q000175:diagnosis*; D011247:Pregnancy; D011296:Prenatal Diagnosis