The biomarkers in conjunction with frataxin expression aim to capture the drugs that restore frataxin expression, such as the HDACi RGFP109/RG2833 and the Nrf2 inducer DMF[29], or reverse the downstream pathomechanism of frataxin deficiency such as interferon gamma-1b[30] and the antioxidant EPI-743[31]. The gene discussed is FXN; the disease is hyperinsulinemic hypoglycemia, familial, 4.