Other previous studies using in vitro flat 2D culture systems have demonstrated that MCs cultured on COL1 gels result in increased proliferation and increased expression of COL1, fibronectin and transforming growth factor beta 1 (TGF-β1), compared to those cultured on COL4 gels [18,19,20], suggesting that abnormal MM components can alter cell functions. Here, FN1 is linked to Miyoshi myopathy.