Hereditary persistence of fetal hemoglobin, ? thalassemia, and the hemoglobin ? ? locus: further family data and genetic interpretations

Abstract

Three Negro kindreds with hereditary persistence of fetal hemoglobin (HPFH) alone and in combination with various other hemoglobin abnormalities including ? thalassemia are presented. Among 11 offspring of 2 women heterozygous for both HPFH and the ? chain mutation Hb B <inf>2</inf>, 5 inherited the HPFH gene and 6 inherited the Hb B <inf>2</inf> gene. In another kindred, a man inferred to be heterozygous for both HPFH and Hb C had 6 children; 3 offspring obtained the Hb C gene and 3 the HPFH gene. Similarly, a woman heterozygous for both Hb S and HPFH transmitted the Hb S gene to one of her 2 children and the HPFH gene to the other. Thus among 19 offspring, no crossovers between the HPFH locus or the Hb ?-? locus were observed. These and earlier data are compatible with deletion of the Hb ? and ? loci as the primary event to explain the genetic origin of HPFH. Genetic considerations indicate that the finding of a single person with a hematologically normal phenotype among offspring of heterozygotes for both the African type of HPFH and a Hb ? or Hb ? structural abnormality would invalidate the deletion model. � 2012 Elsevier B.V., All rights reserved.; MEDLINE� is the source for the MeSH terms of this document.