A new TATA box mutation detected at prenatal diagnosis for beta-thalassemia.

During the course of prenatal diagnosis for beta-thalassemia in Chinese patients, we encountered a mutation that was not detectable by oligonucleotides for the known Chinese mutations. Amplification of the beta-globin gene by the polymerase chain reaction and direct DNA sequencing revealed a previously undescribed -30 TATA box mutation which was carried by the father. Prenatal diagnosis was achieved, and the fetus did not inherit this beta-thalassemia allele.