Pseudohermaphroditism with clinical features of trisomy 19 in an infant trisomic for parts of chromosomes 16 and 18: 47,XY,der(18),t(16;18)(p12;q11)mat.

The case is presented of an infant who was diagnosed clinically as trisomy 18 with pseudohermaphroditism. Cytogenetic studies revealed an extra chromosome which represented a translocation chromosome derived from a balanced, reciprocal translocation between chromosomes 16 and 18: [der(18),t(16;18)(p12;q11)mat]. The infant's mother and a number of her relatives were found to be translocation carriers: ]46,XX,t(16;18)(p12;q11)].