TYPE | HPFH-4; Italian (see Fig. 13) | ||
---|---|---|---|
CAUSE | This type is caused by a deletion that extends 5 kb from the 5' to the delta gene to ~30 kb 3' to the beta gene, thus removing the 3'HS-1 site, located ~20 kb to the beta gene. The 3' breakpoint is close to that of the Indian HPFH-3, while the 5' breakpoint is in close proximity to that of the Spanish (deltabeta)°-thal and Black HPFH-1. The deletion removes the delta and beta genes, the L1 repeat, and ends ~10 kb downstream from the 3'HS-1. | ||
DETECTION | Gene mapping with various probes and enzymes. | ||
PHENOTYPE | Heterozygotes have almost normal hematological parameters: Hb 11.8-16.6 g/dl; MCV 74-91 fl; MCH 24-32 pg; Hb A2 1.7-2.0%. The Hb F value in one patient was 14% but it ranged from 21-30% in the others. The distribution of Hb F in RBC is pancellular and Ggamma levels are 31-39%. Globin chain synthesis was normal. | ||
DISTRIBUTION | Italian HPFH-4 was observed in nine subjects belonging to three different families from Southern Italy. |
REFERENCES | |||
1. | Saglio, G., Camaschella, C., Serra, A., Bertero, T., Rege Cambrin, G., Guerrasio, A., Mazza, U., Izzo, P., Terragni, F., Giglioni, B., Comi, P., and Ottolenghi, S.: Blood, 68:646, 1986. |