TYPE | Croatian (epsilongammadeltabeta)°-Thal (see Fig. 17) | ||
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CAUSE | The condition is characterized by a large deletion removing at least 148 kb; the 5' end is located between the TaqI and BglII sites, ~55 and ~22 kb 5' to the epsilon gene, respectively. The 3' breakpoint is located beyond the BglII site 82 kb 3' to the beta gene. | ||
DETECTION | Gene mapping with different probes and enzymes. | ||
PHENOTYPE | Heterozygotes have a mild anemia with microcytosis and hypochromia, normal levels of Hb A2, and slightly raised Hb F levels. Low MCV (57-66 fl), MCH (19-22 pg), and Hb levels (9.4-11.9 g/dl) are observed. Bone marrow examination revealed hyperplasia and the erythrocyte survival (measured by 51Cr) was 17 days (normal 26-30 days). The Hb F levels were ~2% with the normal Ggamma:Agamma ratio of 40-60%. The in vitro chain synthesis ratio (alpha/beta) for heterozygotes was 1.66. | ||
DISTRIBUTION | Found in a Croatian family from Zagreb, Croatia. |
REFERENCES | |||
1. | Diaz-Chico, J.C., Huang, J.H., Juricic, D., Efremov, G.D., Wadsworth, L.D., and Huisman, T.H.J.: Acta Haematol., 80:79, 1988. |