HDAC4 and retinitis pigmentosa: For example, HDAC4‐NT can cause cardiomyocyte hypertrophy13 or protect cardiac function14, 15; the 1‐289aa fragment can trigger human osteosarcoma cell (U2OS cell) death16, 17; and a short fragment of the HDAC4‐NT preserves photoreceptors and restores visual function in the retinitis pigmentosa.18