MASP-2 levels were significantly lower in RA patients than in controls and relatives (median 181 [21–1200 ng/ml, IQR = 199 ng/ml] vs. 340 ng/ml [42–1200 ng/ml, IQR = 398 ng/ml] and median 181 vs. 285 ng/ml [30–1646 ng/ml, IQR = 329 ng/ml], respectively, Mann-Whitney P<0.0001, Figure 1), but did not differ between patient groups with different clinical characteristics. The gene discussed is MASP2; the disease is rheumatoid arthritis.