TNXB and Ehlers-Danlos syndrome due to tenascin-X deficiency: Tnxb–/– mice did present with mild muscle weakness, histological evidence of myopathy and increased turnover of the ECM in quadriceps muscle (Voermans et al., 2011) as well as altered myofascial force transmission (Huijing et al., 2010), consistent with the mild to moderate muscle weakness observed in clEDS patients (Brady et al., 2017).