A consanguineous family has been typed for HLA‐A, B, C, D, DR and GLO, Bf, C2 and C4 and other red cell markers. The results indicate that an expected Dw7 homozygous sibling is a “Dw1”/Dw7 recombinant, probably derived from a crossing over between DR and D on the paternal haplotypes. The anomalous typings by Dw1 HTCs of the recombinant haplotype are best explained by the likely presence of an additional Lad polymorphism which could be a serologically detectable second epitope on the same molecule as the HLA‐D determinant or in the form of two linked chains, one encoded by HLA‐D and one by another Lad gene in the HLA