Increased STIM1 and ORAI1 expression in platelets derived from patients affected by collagen VI–related disorders. (Ai) Representative western blot of phosphorylated (p) S6 protein and 4E-BP1 protein in peripheral blood platelets of healthy subjects (HS; n = 3) and patients (P) with Bethlem myopathy/UCMD (n = 5). (Aii) Band densities were quantified and expressed relative to HS. Data are mean ± SD. Student t test. (Bi) Representative western blot of STIM1 and ORAI1 protein expression in peripheral blood platelets from HS (n = 3) and P with Bethlem myopathy/UCMD (n = 5). (Bii) Band densities were quantified and expressed relative to HS. Data are mean ± SD. Student t test. (C) Flow cytometry analysis of integrin αIIbβ3 activation (PAC-1 antibody binding) in peripheral blood platelets from HS (n = 3) and P with Bethlem myopathy/UCMD (n = 5) after stimulation with thrombin (0.5 U/mL). Data are mean ± SD. Student t test. ▵, patient 1/F; ▪, patient 2/M; ●, patient 3/M; ▾, patient 4/F; ▴, patient 5/F. Student t test. *P < .05. MFI, mean fluorescence intensity.