α-Globin gene deletion causes α-thalassemia syndromes in two German families

Restriction endonuclease mapping of chromosomal DNA has been used to determine whether the α-globin gene deletion or non-deletion form of α-thalassemia is the underlying molecular defect in individuals of two unrelated German families with α-thalassemia syndromes. The obtained DNA pattern in all cases indicated loss of α-globin genes resulting in-α/αα,--/αα, and--/-α genotypes in αthalassemia-2, α-thalassemia-1, and Hb H individuals respectively. The chromosomes showing loss of one α-globin gene in α-thalassemia-2 and Hb H disease were characterized by the so-called rightward deletion form exhibiting loss of a 3.7 kb DNA fragment in the α-gene cluster.