MMP3 and multiminicore myopathy: Additionally, other studies have shown that the 1171 (6A/6A) mutation in the MMP3 gene is associated with heightened MMD susceptibility with the risk of the (6A/6A) genotype being higher than the (5A/6A) genotype (Wang et al., 2013; Ma and You, 2015; Wang X. et al., 2020).