Felice AE, Webber BB, Huisman TH. Alpha-thalassemia and the production of different alpha chain variants in heterozygotes.
Biochem Genet 1981;
19:487-98. [PMID:
7295286 DOI:
10.1007/bf00484621]
[Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The production of five alpha chain variants (Hb G-Georgia, Hb St. Luke's, Hb Lloyd, Hb Montgomery, and Hb G-Philadelphia) in heterozygotes was evaluated through hematological observations, hemoglobin quantification, and biosynthetic studies. All heterozygotes for Hb St. Luke's and Hb Lloyd and most heterozygotes with Hb G-Georgia and Hb Montgomery had normal hematology and average sigma alpha/beta values of about 1.1. They were assigned a normal genotype (alpha alpha G/alpha alpha), although the proportions of Hb St. Luke's and Hb G-Georgia were low (10 to 13%) and those of Hb Lloyd and Hb Montgomery twice as high (20%). Data from short-term incubations confirmed this genotype for some of these heterozygotes. Isolated Hb St. Luke's and Hb G-Georgia gave low alpha G/beta values (0.2 and 0.3) indicating that these Hb variants were defective at the level of Hb assembly. Isolated Hb Montgomery and Hb G-Philadelphia, however, gave higher alpha G/beta values of 0.6 and 0.8, respectively. A second type of variability existed among Hb G-Georgia (20 vs. 13%), Hb Montgomery (28 vs. 20%), and Hb G-Philadelphia (47 vs. 34%) heterozygotes, in whom the levels of Hb G differed. The occurrence of higher levels of these three alpha chain heterozygosities was associated with hematological or biosynthetic evidence of a mild or moderate alpha chain deficiency due to an alpha-thalassemia-2 heterozygosity (alpha alpha G/alpha O alpha or alpha O alpha G/alpha alpha) or a homozygosity (alpha O alpha G/alpha O alpha), respectively.
Collapse