Two forms of ring 13 in a child with rhabdomyosarcoma.

Mosaicism for two forms of ring 13 was found in a child with embryonal rhabdomyosarcoma of the bladder, minor anomalies, and developmental delay. Her chromosome constitution was 46,XX,r(13)(p11q34)/46,XX,r del(13)(p11q14). Both cell lines were present in lymphocytes and fibroblasts. The cell line with the smaller ring chromosome predominated in both tissues. The child's manifestations reflect the presence of both cell lines.