The measurement of the anti-MDA5 Ab level is a novel tool for monitoring disease activity in RPILD with DM,[14] and hyperferritinemia predicts poor prognosis, especially if the ferritin level is >1600 ng/mL.[15] Therefore, these serum marker levels are very important when considering an earlier initiation of aggressive immunosuppressive therapies and enhancement of treatment. The gene discussed is IFIH1; the disease is isolated hyperferritinemia.