Ethnic intermarriage and its consequences for cystic fibrosis carrier screening.

Cystic fibrosis gene mutations can vary in frequency between different ethnic populations. However, there is a rising trend of ethnic intermarriage in the United States, a situation suggesting that differences in specific mutation frequencies currently apparent in Europe may not persist for long in this country. Therefore, limited mutation screens targeted at specific ethnic groups and risk calculations based on data from more homogeneous European populations may not be appropriate in the United States. The genetic consequences of ethnic admixture are also likely to extend to other recessive diseases (e.g., Tay-Sachs, thalassemia), which, in the past, have been limited largely to particular ethnic, racial, or religious subgroups, with implications for public health agencies overseeing newborn screening programs for genetic diseases and for clinical genetics programs offering population-based carrier-detection programs, carrier risk assessment, and counseling.