[Familial Behçet's disease--a case report].

We reported a case of mother and child affected with Behçet's disease. Both had recurrent oral ulcer, erythema nodosum and arthralgia. Neither had gastrointestinal manifestation nor central nervous system involvement. The mother represented positive pathergy test, but the child did not. Laboratory data suggested no severe sign of inflammatory reaction and increased levels of immunoglobulin D. She was diagnosed as incomplete form, and he was diagnosed as suspicious form of Behçet's disease. On HLA examination, they had common haplotypes of HLA A24, B61, Cw1 and DR8. Additionally, haplotypes of HLA B7, Cw7, DR1, DQ1, were also detected in the mother, and HLA A2, Cw3, DR12, in the child. HLA-B51, which is primarily associated with Behçet's disease, was failed to be demonstrated. Familial involvement of Behçet's disease were described in only 20 cases, 11 of which had positive HLA B51. These findings suggest that molecular genetic examinations for both class I and II antigens will be necessary for a case of familial involvement.