HLA in hypertrophic cardiomyopathy and rheumatic heart disease.

1. HLA antigens were determined in 30 Japanese patients with hypertrophic cardiomyopathy. Several antigens were more common in patients compared with controls, but statistically significant differences were not evidenced. In families one and two, six of seven kindred who inherited HLA-A9 and B7 had the disease. None of five kindred lacking HLA-B7 showed evidence of the disease. In families three and four, affecting family members had HLA-A2 and BW-35. Our finding suggest that the HLA system may play some role in the pathogenesis of hypertrophic cardiomyopathy with familial occurrence. 2. Twenty patients with rheumatic valvular heart disease were also studied. There was no significant difference in frequencies of HLA antigens between patients and controls.