The Prevalence of the Rarer Inherited Haemoglobin Defects in Adult Jamaicans

Summary. The prevalence of several haemoglobin defects, including the traits for β‐thalassaemia (0.8%), hereditary persistence of foetal haemoglobin (0.2%) and the abnormal delta chain haemoglobin, Hb B2 (2.4%), were determined from the combined results of surveys conducted on adults in a suburban and a rural community. Mean Hb A2 levels of 2.6 ± 0.4%, 5.3 ± 0.5% and 2.0 ± 0.2% were found in 639 Hb A homozygotes, seven β‐thalassaemia traits and three traits for hereditary persistence of foetal haemoglobin (HPFH), respectively. Levels of alkali resistant haemoglobin (A.R. Hb) ranged from 0.6 to 7.3% in the β‐thalassaemia traits and were 21.0, 19.0 and 16.0% in the three HPFH traits; the remaining 770 subjects in whom A.R. Hb was measured had a mean value of 0.6 ± 0.6%.