In accordance with the high prevalence of Triple-WT in MM, mutations in the MAPK pathway (mutations in any of the following genes; BRAF, HRAS, KRAS, MAPK2K1, NF1 or NRAS) was significantly less frequent in MM than CM (36.6% vs 81.3%, Fisher’s exact test, p < 0.001). This evidence concerns the gene HRAS and Miyoshi myopathy.