Monosomy for 21pter-q21: case report and assignment of a DNA clone (Fr8-77) to the deleted segment

A 4-month-old Japanese girl with partial monosomy 21 was described. The patient has craniofacial anomalies, a short neck, wide-set nipples, anal atresia, deformed feet, hypertonia, intrauterine growth retardation, and mental deficiency. RFA- and high-resolution GTG-banding chromosome analyses, and Southern- and slot-blot analyses interpreted her karyotype as 45,XX,-2,-21, + der(2)t(2:21)(q37.3;q22.1). The origin of this de novo translocation ascertained by analyses with both QFQ-heteromorphisms and a Fr8-77/BamHI RFLP was paternal. Comparison of the patient with previously reported patients confirmed that her manifestations are consistent with those of monosomy for 21pter-q21. Based on the results of molecular analyses on the present patient, a DNA clone, Fr8-77 (D21S82), was assigned to pter-q21.