The Incidence of H Deficient A₂ and A₂B Bloods and Family Studies on the AH/ABH Status of an A_int, and Some New Variant Blood Types (A_{int H↓}^A₁, A_2↑Hw^A₁, A._2↑B_H^A₁B and A_2↓B_H^A₂B

Abstract

Abstract. The incidence of H deficient A 2 blood samples in the Sheffield area was found to be 1 in 169 and 1 in 13 of group A 2 and A 2 B blood samples respectively. Family studies are described on an A int and on examples of the new variant phenotypes, A intH↓ ., A 2↑H W , A 2↑ B H W and A 2 B H W . The sera of some of the variants contained cold anti‐H s /HI s /HI c /Le bH antibodies, but none contained the Bombay type of anti‐H s active at 37°C. The authors suggest that the modified A status of most of the variants is due to reduced expression of the A 1 genes as a result of insufficient production of H precursor substance by weak H alleles. In paternity testing, it is important that an exclusion should not be based on the occurrence of an A 1 child of a not A 1 group A mating until the A 2 /A 2 B parent(s) have been shown to have a normal H status.