Genetic Disorders in Southeast Asian Immigrants

To the Editor.—  The recent review by Elizabeth Barrett-Connor, MD (239:1901, 1978), reminds physicians of exotic infections and parasitic diseases that could cause illness in refugees from Southeast Asia.In addition to infectious diseases, genetic disorders also have strikingly different prevalences in different ethnic groups. For example, the gene for α-thalassemia is relatively common in Southeast Asians, but most American physicians have never seen a patient with this condition. We have recently counseled a South Vietnamese couple whose first pregnancy occurred in Rhode Island, was complicated by severe edema and hypoproteinemia, and was terminated in the delivery of a hydropic infant who died shortly after birth. The fetal hydrops was found to be due to homozygous α thalassemia, and both parents were found to be heterozygous carriers. During their next pregnancy, prenatal diagnosis using amniocentesis and DNA hybridization of the cultured fibroblasts^1,2 disclosed that the second fetus was also