Moreover, it has been suggested that RC dysfunction may be the cause of the induction of FGF21 expression in muscle; this is supported by the observations that (i) the classic inducers of FGF21 such as fasting and exercise fail to induce FGF21 expression in healthy muscles, and (ii) FGF21 expression was induced in another model of muscle RC deficiency, the Cox10 homozygous knockout mouse 80. The gene discussed is FGF21; the disease is hyperinsulinemic hypoglycemia, familial, 4.