MUC5AC and Bjornstad syndrome: It has been postulated that KLKs could be associated with important events linked to PTD such as: (1) activation of antimicrobial peptides, (2) degradation of the cervical mucus plug by cleaving mucin proteins, and (3) breakdown of the foetal membranes by degradation of extracellular matrix components such as collagens, fibronectin and lamines.80, 81