Unbalanced 13q/21q translocation: a revised study of the case previously reported as 21-monosomy.

Reexamination was made on a male infant previously reported as 21-monosomy. Extensive chromosome banding analyses in the patient and parents disclosed an unbalanced de novo translocation between chromosomes 13 and 21. The patient's karyotype was interpreted as 45,XY,--13,--21+der(13),t(13;21) (q2 or 3;q1 or 2)pat. The patient showed many clinical features characteristic of 13q--syndrome.