To test this hypothesis, we conducted a case-control study of MMD patients by assessing the prevalence of six SNPs of MMP-2, -3, -9 and TIMP-2 (MMP-2 -1575G > A [rs243866], MMP-2 -1306C > T [rs243865], MMP-3 -1171 5a/6a [rs3025058], MMP-9 -1562C > T [rs3918242], MMP-9 Q279R [rs17576], and TIMP-2 -418G > C [rs8179090]). Here, MMP9 is linked to multiminicore myopathy.