The Interaction of Anti 3. 7 Type Quadruplicated α-Globin Genes and Heterozygous β-Thalassemia

Abstract

Human α-globin gene mapping was carried out using a variety of restriction endonucleas es (Bgl II, Bam HI, Hind III, Eco RI, Hpa I, Pvu II and Rsa I) on members of a family from El Salvador and a female from Hawaii, of Chinese descent, whose hematological and clinical parameters were those of β-thalassemia intermedia. Southern blot DNA analysis showed that the β-thalassemia intermedia patients from the above two families had the same anti 3.7 type quadruplicated 7alfa;-genes on the one chromosome, and that they had the α genotype α2, α1α2, α1α2, α1/α2, α1.

The α/β globin synthesis ratios of the three affected Salvadoran patients were around 2.5, and the affected Hawaiian patient was 2.9. These ratios strongly suggest that the additional α-genes in the anti 3.7 type rearrangement are biologically active, thus accounting for the severity of the heterozygous β-thalassemia observed among these patients.