Alpha-thalassaemia: prevalence and pattern in northern Pakistan.

The level of Hb Bart's is directly related to the inheritance of alpha-thalassaemia gene. Hb electrophoresis for Hb Bart's in the cord blood is a very simple method of finding out the prevalence of alpha-thalassaemia gene in a given population. A study was, therefore, carried out to find out the prevalence of alpha-thalassaemia gene in the population of northern Pakistan by estimating the concentration of Hb Bart's in 500 cord blood samples during the period 1986-87 at AFIP Rawalpindi. Hb Bart's was detected in 12 neonates, thus indicating a rate of 2.4% of general population as carrier of alpha-thalassaemia gene. Two distinct groups were recognized. The first group was composed of 9 (75%) neonates, in which Hb Bart's levels varied between 2.0% to 3.5%, while the second group of 3 neonates (25%) showed a level of 5.8% to 6.3%. The former group was considered to be carrying alpha-thalassaemia-2 gene and the latter group as carrier of alpha-thalassaemia-1 gene. Neither Hb H disease nor Hb Bart's hydrops foetalis syndrome was detected in this series.