Beta-globin gene cluster haplotypes in Hb C heterozygotes.
Previous work has suggested that the beta C mutation arose on a relatively rare beta A chromosome with a unique haplotype, and these data have been used to postulate a single origin of the beta C allele. Most characteristic of this haplotype has been the absence of a Hpa I recognition site 3' to the beta-globin gene. We studied 40 patients with Hb SC, 11 with Hb AC, and one with Hb CC. Complete haplotyping was possible on 44 beta C alleles and 3' haplotyping was possible on an additional four beta C alleles. Our results support the predominence of a unique beta C haplotype which is characterized by the absence of the Hpa I site. However, one patient who was homozygous for Hb C had one beta C allele with an atypical haplotype which contained the Hpa I site. It is unclear at this time whether or not this represents a second origin of the beta C mutation.
Talacki
C A
CA
Cardeza Foundation for Hematologic Research, Department of Medicine, Thomas Jefferson University, Philadelphia, PA 19107.
Rappaport
E
E
Schwartz
E
E
Surrey
S
S
Ballas
S K
SK
D000755:Anemia, Sickle Cell / Q000235:genetics; D004247:DNA / Q000032:analysis; D005914:Globins / Q000235:genetics*; D006239:Haplotypes / Q000235:genetics*; D006444:Hemoglobin C / Q000235:genetics*; D006450:Hemoglobin SC Disease / Q000235:genetics; D006579:Heterozygote; D006801:Humans; D005810:Multigene Family / Q000235:genetics*
D005914:Globins; D004247:DNA; D006444:Hemoglobin C