First Report of Filipino β⁰-Thalassemia/β-Thalassemia in a Chinese Family

A pregnant woman living in Fujian Province, southeastern China, presented due to a risk of having a baby with β-thalassemia major, during her second pregnancy, since she and her husband were suspected as β-thalassemia carriers and their affected daughter was a transfusion-dependent patient. Using the common α-thalassemia and β-thalassemia genotypes test, the pregnant woman was diagnosed as a β-thalassemia carrier with β^{IVS-2 - 654 (C→T)}/β^N genotype and her daughter had a homozygosity for IVS - 2 - 654 (C→T) mutation, however, no abnormalities were detected in her husband. SMRT identified a Filipino β⁰-deletion in her husband, and MLPA also revealed an unknown deletion in the HBB gene. Electrophoresis showed approximately 350 bp of the PCR product, and the β-Filipino genotype presented novel fracture fragments ranging from 5,112,884 to 5,231,358 bp, and lacked a 118,475 bp fragment relative to the wild-type sequence. The daughter was therefore diagnosed with the β^{IVS-2 - 654 (C→T)}/β^Filipino genotype. Prenatal diagnosis with umbilical cord blood at 27th week of gestation showed heteroztgosity for IVS - 2 - 654 (C→T) mutation in the fetus and continued pregnancy was recommended. In conclusion, we identified the Filipino β⁰-deletion in a Chinese family, from Fujian area, for the first time, during prenatal screening.