Incidence of ‘Bombay’ (Oh) Phenotype and Weaker Variants of A and B Antigen in Bombay (India)

Abstract

Abstract. Incidence of Oh and weaker A and B variants was studied in 167,404 Indians in Bombay. Eight out of 17 cases of A variants were due to weak A 2 , the majority being among AB individuals. Incidence of all weak A is 1:3,300 among persons possessing the A antigen. The actual incidence of A variants deducting weak A 2 is approximately 1:6,000 persons having the A antigen. Weak B is observed in 1:9,300 persons possessing the B antigen. A x ‐B x variants were twice as common as A m B m types. The O h phenotype is observed in 1:7,600 random persons. The regional and caste distribution of O h individuals showed that 14 out of 22 of the Oh individuals in the present survey and 33 out of 58 among all Oh cases investigated belonged to south‐west districts of Maharashtra.