More precisely, 12 (CDC42, RAC1, RAC2, RHOA, RHOBTB1, RHOD, RHOF, RHOG, RHOH, RHOU, RHOV, and RND1) out of the 21 GTPases analyzed, were expressed at significantly lower levels in MM when compared to healthy controls (p < 0.05). The gene discussed is RAC1; the disease is Miyoshi myopathy.