One of control subjects, included in the normal group (patient G, Table 4), was being monitored for sensitive polineuropathy, unilateral sacroiliitis (HLA B27 absent), positive titers of RF, antinuclear, anti-U1 RNP and anti-CCP antibodies, with no signs and symptoms of arthritis, both at the time of the study and in her medical history. This evidence concerns the gene U1 and arthritic joint disease.