Mutation study for the HBB gene was conducted for four ß-haemoglobinopathies, HbC [β6; AA Glu→Lys (E→K)], HbD [β121; AA Glu→Gln (E→Q)], HbE [β26; Glu→Lys (E→K)], and HbS [β6; Glu→Val (E→V)]. The gene discussed is HBD; the disease is hemoglobinopathy.