Heritable fragile sites on human chromosomes. VII. Children homozygous for the BrdU-requiring fra(10)(q25) are phenotypically normal.

A brother and sister have been detected who are homozygous for the bromodeoxyuridine (BrdU)-requiring fragile site at 10q25. The children are phenotypically normal, indicating that homozygosity for this fragile site is harmless, at least during childhood.