No Role of Antibody in Arthritis Heritability
But overall heritability is 66 percent
THURSDAY, April 9 (HealthDay News) -- The presence of anti-citrullinated protein antibodies (ACPA) in patients with rheumatoid arthritis, which are highly predictive of the disease course, does not have a role in the heritability of the disease, according to research published in the April issue of Arthritis & Rheumatism.
Diane van der Woude, M.D., from Leiden University Medical Center in the Netherlands, and colleagues examined the heritability of rheumatoid arthritis in 148 twin pairs (64 monozygotic and 84 dizygotic), where at least one twin of each pair had rheumatoid arthritis.
The researchers found that the overall heritability was 66 percent. The presence of ACPA had little effect, with a heritability of 68 percent for ACPA-positive disease and 66 percent for ACPA-negative disease. HLA-DRB1 shared alleles that had been shown to be associated with ACPA-positive arthritis explained 18 percent of the genetic variance for ACPA-positive disease but only 2.4 percent of the variance for ACPA-negative disease, the authors report.
"Our findings thus show that ACPA-positive and ACPA-negative rheumatoid arthritis have a similar heritability of [about] 66 percent," van der Woude and colleagues conclude. "These data indicate that genetic predisposition plays an important role in the pathogenesis of ACPA-negative rheumatoid arthritis, for which most individual genetic risk factors remain to be identified."