Nonetheless, on the organismal level, SUCLA2‐deficient mice present with severe muscular phenotypes suggestive of mitochondrial myopathy, which is further evidenced by elevations of circulating FGF‐21, lower serum creatinine suggestive of reduced muscle mass, mitochondrial proliferation and Type 1 fibre predominance (Figures 2e–f, 7 and 8) [4, 28, 31, 33, 34]. The gene discussed is FGF21; the disease is Mitochondrial myopathy.