TYPE | Black (deltabeta)°-Thal (see Fig. 14) | ||
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CAUSE | A deletion that removes 12 kb of DNA extending from ~2.4 kb 5' to the delta gene to 200 bp at the 3' end of the beta gene. The inverted Alu I repeats 3' to the beta gene remain intact. | ||
DETECTION | Gene mapping with various enzymes and probes. | ||
PHENOTYPE | This deletion was reported in an American Black woman who was a compound heterozygote for this deletion and the betaS gene. She was asymptomatic with a mild anemia and 24.8% Hb F. Her husband and daughter had similarly high Hb F levels of 22.4 and 25.4%, respectively; however, the husband and daughter were found to be compound heterozygotes for the betaS gene and the Ghanaian type HPFH (HPFH-2). The patient's hematological data: Hb 11.4 g/dl; PCV 0.34 l/l; RBC 4.0 x 1012/l; MCV 85 fl; MCH 28.5 pg; MCHC 33.5 g/dl; Hb S 72.5%; Hb F 24.8%; Hb A2 2.7%; alpha/non-alpha biosynthetic ratio 1.07. Hb F distribution was pancellular; Ggamma levels in Hb F were not reported. No simple heterozygotes have been described. | ||
DISTRIBUTION | This rare deletion has only been found in one American Black woman. |
REFERENCES | |||
1. | Anagnou, N.P., Papayannopoulou, Th., Stamatoyannopoulos, G., and Nienhuis, A.W.: Blood, 65:1254, 1985. |