[Giant cell arteritis--a genetically-determined disease?].

We report on two siblings with giant cell arteritis (GCA) and polymyalgia rheumatica (PMR). Temporal artery biopsies revealed GCA in three cases, and sclerosis of the wall of the temporal artery in one case. The HLA haplotype was identical in the first pair, and in the second pair HLA-A2, HLA-B39 and HLA-DR53 were identical. In three patients HLA-DR4 was demonstrated. Cases of familial aggregation of GCA have been reported in the literature. In several reports an increased prevalence of HLA-DR4 was described (about 40% of patients with GCA, compared with about 13% in the European population). HLA-DR4 was observed in three of our four patients and a haploidentity was found in one pair. Based on our observation and the results published in the literature, it seems probable that giant cell arteritis--a typical disease of advanced age--has at least partially a genetic basis.