MmD may be associated with recessive mutations in the selenoprotein N1 gene (SEPN1, also known as SELENON) [26],—as well as other genes such as MYH2 [27, 28], UNC45B [29], MYH7 [30], TTN [31], MEGF10 [32], SECISBP2, ACTA1, ACTN2, CCD78 [33], and FXR1 [34]—but mutations in RYR1 had been increasingly described [22, 23, 25, 35]. Here, RYR1 is linked to multiminicore myopathy.