RESUMO
Fetal haemoglobin (Hb F) synthesis has been studied in 22 cases of sickle cell anaemia (SS) from Saudi Arabia and compared with an equal number of cases of African origin. Among the Saudi Arabs y chain synthesis ranged from 4.0 percent to 19.9 percent of the total non-x chain synthesis (mean 8.1 percent) while the corresponding range for the Negro cases was <0.3 percent to 4.6 percent (mean 1.7 percent). In both groups the peripheral blood HB F level was on average 3-4 times higher than the proportion synthesized, indicating that the selective survival of Hb F containing cells (F cells) was an important factor in determining the final Hb F levels. Among the Saudi Arab cases there was a significant negative correlation between the degree of F cell enrichment and either the Hb F level or the percentage y chain synthesis. No such correlation was observed among the Negro cases. A high proportion of the cases in both groups were carriers of x thalassaemia in addition to SS, but no effect of x talassaemia on Hb F production was observed (AU)
