W4(4a) and W6(4b) in diverse human populations. Demonstration of their genetic identity in population and segregation studies.

The status of the W4, W6 system as related to the HL-A system was re-evaluated by means of segregation and mating studies in 200 Dutch families with 755 children. Inclusion analyses were performed on the Fifth Workshop human populations and related to a reference analysis on the main file in Leiden. The results of the mating and segregation analyses showed a good fit for W4 and W6 as a genetic system. The inclusion analyses showed a high degree of concordance. Based on those results, and other cited evidence, it was suggested that W4 and W6 may represent the basic substance of the HL-A antigens in the FOUR series.