Since myositis could emerge in the context of some connective tissue disorders, testing for some other laboratory markers, including antinuclear antibodies (ANA), anti-smooth muscle antibodies (ASMA), perinuclear antineutrophil cytoplasmic antibodies (p-ANCA), cytoplasmic antineutrophil cytoplasmic autoantibody (C-ANCA), anticyclic citrullinated peptide (anti-CCP), rheumatoid factor (RF), anti-double-stranded DNA (anti-ds DNA), complement component 3 (C3), complement component 4 (C4), and anti-Ro were done, which were all in the normal range. The gene discussed is C3; the disease is myositis disease.