Hb Lansing (HBA2: c.264C>G) and a New β Promoter Transversion [-52 (G>T)]: An Attempt to Define the Phenotype of Two Mutations Found in the Omani Population

We report two examples showing how problematic it can be to define the phenotype of new or rare globin genes mutations. We describe two mutations observed for the first time in the Omani population: the first was found in the consanguineous parents of a deceased newborn with hepatomegaly, cardiomegaly and severe hemolytic anemia, putatively homozygous for the rare Hb Lansing (HBA2: c. 264C>G) variant. The second is a novel beta-globin gene promoter mutation [-52 (G>T)] observed in four independent patients. Two with borderline/elevated Hb A(2), alpha-thalassemia (alpha-thal) and hypochromic red cell indices, and two heterozygotes for Hb S (HBB: c. 20A4T), alpha-thal and with Hb A/Hb S ratios possibly indicating a very mild beta(+)-thalassemia (beta(+)-thal) mutation.