Fetal haemoglobin level--effect of gender, age and haemoglobin disorders.

Fetal haemoglobin (Hb F) levels shows significant variations in health and disease states. In this study we investigated Hb F level in 75 cord bloods, 1266 healthy individuals, 1582 Hb S heterozygotes, 464 sickle cell anaemia, 93 Hb S/beta(0) -thalassaemia and 65 beta-thalassemia major patients. The age range of the study groups varied from newborn to over 60 years of age. Hb F level was measured by an alkali denaturation procedure and by radial immunodiffusion. The ratio of the level of G gamma-globin chains to the level of A gamma-globin chains (G gamma/A gamma) was determined in the patients group by high performance liquid chromatography. The Hb F level was significantly higher in the sickle cell anaemia and beta-thalassemia major patients compared to the Hb S heterozygotes and the normal individuals. Within each group Hb F level was higher in the female population compared to the age-matched male groups. This difference was statistically significant (P < 0.05) in the sickle cell disease patients and beta-thalassemia major patients but not in the normal individuals. After the age of 30 years, the difference in the value of Hb F in the male and female population become more apparent (P < 0.05) in the sickle cell disease and beta-thalassaemia major patients. No statistically significant sex differences were found in the G gamma/A gamma ratio in the patient groups, and the range of G gamma/A gamma ratio in the patients groups were similar to those in the control group. The results showed that age, sex and genetic disorders of haemoglobin are factors that affect Hb F level and indicate the possible involvement of an X-linked factor in control of Hb F production.