TTN and Ehlers-Danlos syndrome: According to certain results, obtained using monoclonal antibodies to phosphoserine pS26, a three-fold increase in the degree of phosphorylation of the PEVK region (located in zone I of the molecule) of titin in the quadriceps muscle of patients with Ehlers-Danlos syndrome was accompanied by a decrease (by ∼20%) in the content of this protein (Ottenheijm et al., 2012).