Male siblings with Takayasu's arteritis suggest genetic etiology.

Takayasu's arteritis is a nonspecific arteritis involving the aorta and its major branches. The disease mainly affects young females and familial incidence is uncommon. In this paper, two rare cases of male siblings with Takayasu's arteritis and the results of their HLA typing are described. The HLA haplotype of the two cases was completely identical--A2-B40-Cwl and A24(9)-Bw59-Cwl, DR2, and DR4. It is reported that Bw52(5) is strongly associated with the disease. However, in our cases, Bw52(5) was not found, while DR2 and DR4, which have been reported in association with several autoimmune disease, were detected. Accordingly, in these cases, genetic factors might be associated with the pathogenesis of the disease through an autoimmune mechanism.