familial occurrence of three types of autoantibodies , viz . rheumatoid factors , antinuclear antibodies and thyroid autoantibodies , was investigated in two population series : twins from the finnish twin registry representing the adult twin population living in an urban area ( 76 monozygotic and 82 dizygotic same-sex twin pairs ) and siblings from a middle-aged rural population subject to an ongoing epidemiological study ( 311 sibling groups comprising 801 subjects and 584 married couples ) .
C0004358
autoantibodies
C0003243
antinuclear antibodies