The inheritance of Felty's syndrome in a family with several affected members.

A family in which 3 siblings had Felty's syndrome is described. All affected family members shared the common haplotype HLA-A2, B15, Cw3 and DR4. In addition, all affected siblings possessed the A2 and ABO phenotype. Four unaffected siblings possessed either the HLA-A2, B15, Cw3 and DR4 haplotype or the A2 ABO phenotype or neither but not both. We believe our data support the hypothesis that multiple genetic factors are involved in the predisposition of family members to Felty's syndrome.