Known and new delta globin gene mutations and their diagnostic significance
Bouva, M.J.; Harteveld, C.L.; van Delft, P.; Giordano, P.C.
Haematologica 91(1): 129-132
2006
ISSN/ISBN: 0390-6078 PMID: 16434382 Document Number: 596270
Mutations in the delta-globin gene (HBD, MIM# 142000) are not pathologically relevant. However, since high HbA(2) levels are diagnostic for beta-thalassemia trait and a lowered level for an alpha- or delta-mutation, co-inheritance of delta- and beta-gene defects may lead to misinterpretation of diagnostic results. We examined 29 cases with low HbA2 level diagnosed in our laboratory, in the presence or absence of a second HbA2 fraction. We found a 8 globin gene mutation in 20 cases.In total four different known mutations were found, three structural and one expressional. Moreover, two new defects were observed, one causing a structural abnormality and one a delta-thalassemia.The structural abnormality HBD c.431A -> G (p.His144Arg)(delta cd 143 CAC -> CGC) was homologous to the P-globin gene variant called Hb-Abruzzo and we have named this mutation HbA(2)-Abruzzo. The new delta-thalassemia defect HBD c.-118C -> T (delta -68 C -> T) has no homology on the beta-globin gene (HBB, MIM# 141900). All mutations caused a low HbA(2) level and through this could lead to misdiagnosis when inherited together with a beta-thalassemia.