The haematological puzzle of Hb J Cape Town is partly solved

Summary. Molecular studies have shown that the mutation giving rise to Hb J Cape Town (α92 arggln) is situated on a chromosome from which the other α-globin gene has been deleted. The −α3.7 deletion has resulted from crossing-over within segment I of the Z region of homology. There appears to be an unusually high proportion of the variant haemoglobin in heterozygotes which cannot be explained by gene dosage alone.