KRAS and Miyoshi myopathy: However, when characterized in MM patients (our data, the CoMMpass dataset), and in the one case known from an MGUS sample [40] KRAS exon-4 mutations were always present with high allele frequency at DNA and RNA level (e.g., higher than for the common exon-2 and exon-3 mutations p.G12 and p.Q61), suggesting that they are a major determinant in the rise to clonal dominance.