While next-generation sequencing reveals MM BAP1 mutation rates in the order of 20–30% (Guo et al., 2015; Bueno et al., 2016; Bott et al., 2011), immunohistochemical analysis has identified loss of BAP1 function in up to 67% of MM tumours (Nasu et al., 2015) opening our biomarker-driven approach to a significant proportion of MM patients. Here, BAP1 is linked to Miyoshi myopathy.