Skin biopsy findings varied across autoantibody subgroups; in anti-TIF1γ patients, biopsies showed interface dermatitis, mucin deposition, atrophic epidermis with hyperorthokeratosis, and mild perivascular lymphocytic infiltration; anti-Mi2 patients presented with interface dermatitis; anti-NXP2 patients exhibited keratinocyte necrosis, and vascular necrosis; and anti-MDA5 patients displayed perivascular dermatitis with interstitial mucin deposition. The gene discussed is MUC5AC; the disease is dermatitis.