A family with segregating triplicated alpha globin loci and beta thalassemia.
In this article we report a Sardinian family, in which a beta-thalassemia gene and a triple alpha-globin loci, counterpart of the rightward deletion type alpha-thalassemia-2, were segregating. The analysis of the genotype-phenotype correlations in the different family members allowed us to give an outline of the manifestations associated with different genotype combinations. The heterozygote for the triple alpha-loci showed no consistent abnormal clinical or hematologic characteristics and presented balanced alpha/beta-globin chain synthesis. In the homozygous state for this lesion, the only phenotypic expression was a slightly imbalanced globin chain synthesis. The combination of heterozygous beta-thalassemia with the heterozygous state for the triple alpha-globin loci produced no clinical manifestations and showed a hematologic phenotype indistinguishable from that of heterozygous beta-thalassemia. On the other hand, the combination of the homozygous state for the triple alpha-globin gene loci and the heterozygous state for beta-thalassemia produced a clinical picture of thalassemia intermedia with a very mild clinical course, minor increase of fetal hemoglobin (HbF) levels, and a pronounced imbalance of globin chain synthesis.
D000328:Adult; D002874:Chromosome Mapping; D004262:DNA Restriction Enzymes / Q000378:metabolism; D005838:Genotype; D005914:Globins / Q000096:biosynthesis / Q000235:genetics*; D006801:Humans; D007558:Italy; D008297:Male; D010375:Pedigree; D011110:Polymorphism, Genetic; D013789:Thalassemia / Q000235:genetics*
D005914:Globins; D004262:DNA Restriction Enzymes