HbH which is a form of NTDT has a diverse phenotypic presentation depending on the degree of alpha globin chain deficiency which in turn relates to the underlying a-thalassemia mutations with hemolysis being the dominant clinical symptom .
GM06160 also gave anomalous results in testing for a-thalassemia. Southern blot analysis showed an unusual banding pattern with a [zeta]-globin gene probe, with additional smaller bands in BamHI and BglII digests (an EcoRI digest appeared normal).
Others have evaluated its performance with various other technologies12,13 and in the analysis of complicated a-thalassemia and ss-thalassemia syndromes in Southeast Asia14 or rare hemoglobin variants8.
For patient 1, a routine a-globin gene configuration Southern analysis was performed to screen for the presence of the [--.sup.SEA] a-thalassemia deletion, a common amelioration factor of severe ([alpha]-thalassemia (7).
It is prevalent in South-East Asian, Middle Eastern and Mediterranean population but intermediate and severe forms are rare in North America and Northern Europe.1,2 Multiple types of deletions or mutations have been found to influence the clinically observed heterogeneous phenotypes of a-thalassemia cases.3