A low frequency mosaicism for monosomy 21 in a live born female

摘要

Monosomy 21, whether homogeneous or as a mosaicism, is very uncommon. We report here a 3-month-old white female with a low degree of monosomy 21 in the blood karyotype (6.5, 110 cells counted) but not in the skin fibroblasts, which contained only the normal chromosome complement.