HLA antigens in multiplex families with isolated congenital heart disease.

Twelve multiplex families with isolated congenital heart diseases (CHD) were included in the study. In 9 families the types of CHD in the living sibs were concordant and in the other 3 were discordant. All families were subjected to the following: (1) Pedigree construction, (2) clinical examination of the parents, affected and unaffected sibs, (3) investigations of patients, to establish the diagnosis, (4) chromosomal analysis for the patients, (5) HLA antigen typing for the parents, affected and unaffected sibs for 9 antigens at the A locus, 15 at B and 6 at the DR locus. The results can be summarized as: (a) sibs with two different types of CHD showed identical haplotypes; (b) the segregation of haplotypes among disease sibpairs is inconsistent with Mendelian segregation; (c) increased frequency of concordant HLA haplotypes among diseased siblings; (d) Morton's exact test revealed that the data best fit a hypothesis of a recessive susceptibility gene, linked to HLA.