Evidence for genetic anticipation in nodal osteoarthritis

OBJECTIVE Evidence was sought for genetic anticipation (disease occurring at an earlier age in subsequent generations, with increasing severity) in nodal osteoarthritis (NOA). METHODS Age at symptom onset and disease severity was compared within 30 parent/offspring pairs with NOA. Correlation between the offspring age of disease onset and the parental age at conception was also assessed. RESULTS The age at onset of nodal symptoms was earlier in the offspring (43 years (95% confidence intervals (CI) 38 to 47) v 61 (CI 58 to 65); mean difference 18 years (CI 13 to 22): p< 0.001) as was large joint symptom onset (48 years (CI 41 to 55) v 67 (CI 61 to 73); mean difference 20 years (CI 13 to 27): p< 0.01). A negative correlation existed between age of offspring symptom onset and parental age at conception. Fifteen (50%) offspring had similar or more extensive disease than their parents. CONCLUSIONS These results suggest genetic anticipation occurs in NOA and if confirmed a search for trinucleotide repeats is warranted.