HBA2 and hemoglobinopathy: DNA analysis should always be performed in couples at risk (both partner carriers of hemoglobinopathies and/or triplication-quadruplication of α globin genes) in cases where the first level tests are not decisive or in couples where one partner is a carrier of alpha- and the other of beta thalassemia in order to exclude the possibility that the beta trait is masking an alpha trait, thus underestimating the risk of HbH in the fetus or vice versa.