As decreased sialic acid production, a final product of GNE (glucosamine UDP-N-acetyl-2-epimerase/N-acetylmannosamine kinase) due to loss of function mutations in epimerase or kinase domain of GNE, is closely associated with the pathogenicity of GNE myopathy, the levels of sialic acid production in each mutant hPSCs or myoblasts derived from these mutant iPSCs (including one VUS) have been used to predict the clinical significance [9]. This evidence concerns the gene GNE and myopathy.