The prevalence of recurrent spontaneous abortions, cancer, and congenital anomalies in the families of couples with recurrent spontaneous abortions or gestational trophoblastic tumors.

This study extends our previous work on the genetics of recurrent spontaneous abortion and of gestational trophoblastic tumors in an ethnically homogeneous population of Chinese in Taiwan by comparing the prevalence of recurrent spontaneous abortions, cancer, and congenital anomalies in the first-, second-, and third-degree relatives of the index couples to that of normally fertile couples from the same population. The rationale for this study was to provide another test for our hypothesis that genes linked to the major histocompatibility complex are responsible for the diseases in the index couples. If they are, these genes should segregate with a higher frequency in the relatives of the index couples than in the relatives of normally fertile couples and lead to a higher prevalence of these diseases in the extended families. Such a difference was found and adds support to our hypothesis that major histocompatibility complex-linked genes affect growth, development, and susceptibility to cancer.