As expected, the RNF213 RING domain mutations C3997Y, P4007R, and D4013N, as well as the MMD-associated R4810K mutant that has been shown to affect its E3 ligase activity [11], display considerably lower levels of Cav-1 ubiquitination than WT RNF213, and levels comparable to that of the RING-dead mutant C3997A. The gene discussed is CAV1; the disease is multiminicore myopathy.