OBJECTIVETo conduct prenatal diagnosis on the couples carrying Thailand deletion (--THAI) alpha-thalassemia 1 and at high risk of having fetus with alpha-thalassemia.

METHODSGenotypes of couples and fetuses were analyzed by PCR and DNA sequencing.

RESULTSFour pregnant women were patients with Hb H diseases of --THAI compounding with alpha-thalassemia 2, while their husbands were heterozygote of the Southeast Asian type alpha-thalassemia 1 (--SEA). Another 5 families, either husbands or wives were heterozygote of --THAI or --SEA. The genotypes of their fetuses were as follows: 2 cases with Hb Bart's hydrops fetalis syndrome, 1 Hb H disease, 4 alpha-thalassemia heterozygote and 2 normal. The DNA sequencing approved the PCR results.

CONCLUSIONThe study on prenatal diagnosis of Thailand deletion alpha-thalassemia 1 is of importance to the genetic counseling and prenatal diagnosis of alpha-thalassemia.