CTD: connective tissue disease; MPO: myeloperoxidase; AI: antibody index; PR3: anti-proteinase 3; LK: liver-kidney; TTG IgA: tissue transglutaminase immunoglobulin A; ALT: alanine transaminase; ALP: alkaline phosphatase; INR: international normalized ratio. Here, TGM2 is linked to connective tissue disorder.