title: Is haemoglobin G alpha Philadelphia linked to alpha-thalassaemia?
abstract: The question, "Is Hb G alpha Philadelphia linked to alpha-thalassaemia?" was first posed because the abnormal haemoglobin is found in heterozygotes at a concentration greater than 25%, the proportion predicted from a 4 alpha-chain gene model. Globin chain biosynthesis was studied in a West Indian family in which one parent had beta + thalassaemia and the other was heterozygous for the G alpha Philadelphia chain gene. The former had a globin chain production ratio alpha/beta well above 1, while the latter had a ratio significantly less than 1. One child of the marriage had inherited the beta + thalassaemia from one parent and the G alpha Philadelphia chain gene from the other and showed the typical picture of alpha/beta-thalassaemia (alpha/beta ratio slightly above normal). It is explained in the discussion that the evidence favours a close linkage of 2 alpha-chain genes.
mesh_terms: D044383:Black People; D005260:Female; D005787:Gene Frequency; D005796:Genes; D008040:Genetic Linkage; D005838:Genotype; D005914:Globins / Q000096:biosynthesis; D006455:Hemoglobins, Abnormal / Q000096:biosynthesis*; D006579:Heterozygote; D006801:Humans; D008297:Male; D010375:Pedigree; D010641:Phenotype; D013789:Thalassemia / Q000235:genetics*
chemical_list: D006455:Hemoglobins, Abnormal; D005914:Globins