Fetal loss and familial chromosome 1 translocations.

A structural abnormality of chromosome No. 1 was found in two families who had a history of repeated abortions. The propositus in Family H was a low birth weight, malformed infant who had a partial trisomy of 1g. His mother and a sibling were balanced carriers of a t(1;4) (q25;135). In family B, the 29-year-old phenotypically normal propositus and his mother were found to be balanced carriers of a t(1;12) (p12;q24). It is suggested that the fetal wastage in both families was related to the abnormal karyotypes of the parents. These two families also provide an opportunity to further understand the effect of an abnormality of chromosome number 1 on phenotype.