To investigate whether there is evidence for genetic anticipation in rheumatoid arthritis (RA) in Europe.
Cross sectional comparison of data from all affected parent-offspring pairs identified among (1) the RA population attending our department and (2) a large cohort of families from RA probands with both parents alive recruited by the European Consortium on RA families (ECRAF) for association studies. Longitudinal comparison between probands with and without parental RA. We used prospectively collected data on disease activity, therapies, and radiological outcomes from our Dutch inception cohort of patients with early RA during the first 6 years of followup.
From a total of 683 Dutch and 170 European patients we identified 28 Dutch and 21 European parent-offspring pairs with RA. Probands with parental RA had an earlier disease onset compared with affected parents (Dutch p < 0.002, European p < 0.0001). In Dutch patients, the prevalence of HLA-DR4, DR4 double dose, and shared epitope (SE) double dose was slightly higher in probands with parental RA than in those without [odds ratios (95% CI) 2.0 (0.7-5.8), 2.79 (0.8-9.4), and 2.12 (0.6-8.7), respectively]. The same was true for European probands concerning SE double dose [OR (95% CI) 1.76 (0.6-8.7)]. No other relevant differences in demographic or clinical indices were found between probands with affected parents and those without. Disease course (Disease Activity Score) and therapies used during the first 6 years of followup were similar in Dutch patients with and without parental RA. Radiological damage at baseline was lower in the former group and this difference persisted after 3 and 6 years.
Our data suggest that genetic anticipation in RA does occur in terms of an earlier disease onset in the offspring. Despite a slightly higher prevalence of HLA alleles encoding for the SE, probands with confirmed parental RA had no worse outcome than those without.