Congenital diaphragmatic hernia in a family segregating a reciprocal translocation t(5;15)(p15.3;q24).

Congenital diaphragmatic hernia (CDH) is a relatively common malformation of unknown cause with high mortality due to hypoplasia of the lungs and pulmonary hypertension. We studied a family in which two fetuses had CDH, and two pregnancies resulted in first trimester missed abortions. Both fetuses with CDH had an apparently normal karyotype. In a subsequent pregnancy, fluorescent in situ hybridization analysis of amniocytes showed a balanced translocation 46,XY, t(5;15) (p15.3;q24) also present in the mother and in a normal child, suggesting that the diaphragmatic hernia in the first two fetuses was caused by a cryptic unbalanced translocation. This hypothesis is supported by a previous observation of CDH in a distal deletion of 15q as part of a multiple congenital anomalies syndrome. It is suggested that a gene distal to 15q21 is important for the normal development of the diaphragm.