Regional enteritis and HLA concordance in multiple siblings.

A familial predisposition to ulcerative colitis and Crohn's disease is well established, and linkage of a susceptibility gene to the HLA gene locus has been postulated. We report here a family of five children, at least four and probably all five of whom have Crohn's disease. HLA studies of four of the five showed three with the same paternal haplotypes (A2, B44), all four with the same maternal haplotypes (A30, B17), and three of the four to be HLA identical. combination of this data with four studies in the literature shows an excess of shared haplotypes among sibling pairs with disease, but the excess does not reach statistical significance. Thus, although the data shows a trend, Crohn's disease susceptibility linkage to the HLA gene locus is still unsettled. Lymphocytotoxic antibody was present in two of the four children but in neither parent.