TYPE | HPFH-5; Italian (see Fig. 13) | ||
---|---|---|---|
CAUSE | The deletion starts 3.2 kb 5' to the delta gene, removes both the delta and beta genes, and terminates 0.7 kb 3' to the beta gene; the total length of the deletion is 12.9 kb. The size of this deletion is similar to those of Black, Sicilian, Laotian, and Thai (deltabeta)°-thal. The Italian HPFH-5 is the smallest of the HPFH deletions reported thus far. | ||
DETECTION | Gene mapping and sequencing. Direct sequencing of PCR-amplified fragments spanning the 5' and 3' breakpoints showed that the 5' breakpoint is located 141 bp downstream from the XbaI site in the inter-Alu region, and the 3' breakpoint between positions 692 and 695 bp 3' to the poly A site of the beta gene. | ||
PHENOTYPE | The hematology is nearly normal in the two heterozygotes: Hb 14.0 and 13.6 g/dl; MCV 81 and 80 fl; MCH 25 and 26 pg; Hb A2 2.1 and 2.0%; Hb F 20.0 and 16.0%; Agamma 83.0 and 85.0%; alpha/non-alpha 1.15. Distribution of the Hb F in the erythrocytes, evaluated by immunofluorescence with an anti-gamma-monoclonal antibody, was pancellular. The possibility of the coexistence of nondeletional Agamma-HPFH, which may be responsible for the marked elevation in the Agamma chain synthesis, was excluded by sequencing of the Agamma promoter region from position -264 to the Agamma gene Cap site. | ||
DISTRIBUTION | HPFH-5 was found in two brothers from Sicily. |
REFERENCES | |||
1. | Camaschella, C., Serra, A., Gottardi, E., Alfarano, A., Revello, D., Mazza, U., and Saglio, G.: Blood, 75:1000, 1990. |