COL1A2 and hypertensive disorder: Plasma levels of C-terminal propeptide of procollagen type I (PICP), which is released as a byproduct of the maturing process of procollagen type I, were shown to be correlated with the myocardial PICP content and collagen volume fraction as determined histologically in hypertrophic cardiomyopathy (53) and hypertension patients (54).