Hemoglobin Delta (HBd)

The delta (HBD) and beta (HBB) genes are normally expressed in the adult: two alpha chains plus two beta chains constitute HbA, which in normal adult life comprises about 97% of the total hemoglobin. Two alpha chains plus two delta chains constitute HbA-2, which with HbF comprises the remaining 3% of adult hemoglobin. De Angioletti et al. (2002) characterized mutations and haplotypes of the HBD gene in 2 regions of southern Italy. They screened approximately 10,000 students in Basilicata and found 53 carriers of HBD variants in 43 unrelated families; in Campania, patients were ascertained through a routine thalassemia counseling service. They found 6 novel mutations and stated that 46 HBD mutations had been previously characterized, of which 30 were from the Mediterranean area .