TYPE | Irish (epsilongammadeltabeta)°-Thal (see Fig. 17) | ||
---|---|---|---|
CAUSE | A large deletion with a minimum size of 205 kb extending from at least 65 kb 5' to the epsilon gene, thus removing all the major controlling sequences (5'HS-1 to 5'HS-4). This deletion extends for at least 90 kb 3' to the beta gene and ends near the 3' deletion breakpoints associated with HPFH-1, HPFH-2, and the Spanish deltabeta°-thal. | ||
DETECTION | Gene mapping with different enzymes and probes. | ||
PHENOTYPE | Heterozygotes have microcytic anemia and imbalanced alpha/beta globin chain synthesis ratios. They all had normal Hb A2 and Hb F levels. A typical hematology of an affected individual was: Hb 13.6 g/dl; MCV 65.3 fl; MCH 19.8 pg; Hb A2 3.0%; Hb F 1.1%; alpha/beta ratio 2.7. Blood smear showed anisocytosis and poikilocytosis. | ||
DISTRIBUTION | Found in a large Irish family. |
REFERENCES | |||
1. | Fortina, P., Delgrosso, K., Werner, E., Haines, K., Rappaport, E., Schwartz, E., and Surrey, S.: Hemoglobin, 15:23, 1991. |