TRISOMY 15 MOSAICISM AND UNIPARENTAL DISOMY (UPD) IN A LIVEBORN INFANT

We describe a liveborn infant with uniparental disomy (UPD) with triso my 15 mosaicism, Third trimester amniocentesis yielded a 46,XX/47,XX, + 15 karyotype, Symmetrical growth retardation, distinct craniofacies, congenital heart disease, severe hypotonia and minor skeletal anomali es were noted, The infant died at 6 weeks of life, Peripheral lymphocy te chromosomes were ''normal'' 46,XX in 100 cells, Parental lymphocyte chromosomes were normal, Skin biopsy showed 47,XX, + 15 in 80% of fib roblasts and results were equivalent in fibroblasts from autopsy lung tissue, Molecular analysis revealed maternal uniparental heterodisomy for chromosome 15 in the 46,XX cell line, We describe an emerging phen otype of trisomy 15 mosaicism, confirm that more than one tissue shoul d be studied in all cases of suspected mosaicism, and suggest that UPD be considered in all such cases. (C) 1996 Wiley-Liss, Inc.