CASE OF 46,XX 47,XY,+21 CHIMERISM IN A NEWBORN-INFANT WITH AMBIGUOUS GENITALIA/

We describe whole-body chimerism in a newborn infant with small phallu s, pseudo-vaginal perineal hypospadias, and a bifid scrotum containing gonads. The human testis determining factor gene (SRY) was detected b y PCR amplification. GTG-banding chromesome analysis in peripheral blo od lymphocytes and cultured fibroblasts derived from right cubital ski n showed a 46,XX/47,XY, +21 karyotype. Their ratios in each cell line were 294:5 and 178:7, respectively. QFQ-banding chromosome analysis do cumented 3 heteromorphic satellites on trisomic chromosomes 21 in the 47,XY,+21 cell line and a homozygous satellite pattern in the 46,XX ce ll line. Heteromorphic patterns of chromosomes 4, 13, 14, and 22 were also different between the two cell lines. To our knowledge, such diso my/ trisomy chimeras have not been described previously. (C) 1994 Wile y-Liss, Inc.