Familial Risks and Heritability of Rheumatoid Arthritis: Role of Rheumatoid Factor/Anti–Citrullinated Protein Antibody Status, Number and Type of Affected Relatives, Sex, and Age

Abstract

The pattern of risks suggests that familial factors influence RA in men and women equally and that these factors are of less importance for late-onset RA. Familial factors are more important for seropositive RA, but there is significant familial overlap between seropositive RA and seronegative RA. Even if the familial risk is assumed to be completely due to genetics, the observed risks suggest that heritability of RA is lower than previously reported, in particular for ACPA-negative RA.