Four BMPs differed in the PCOS cohort (whole set without matching for body mass index (BMI) or insulin resistance (IR)): periostin (p = 0.05), cathepsin L (p = 0.05) and osteocalcin (p = 0.02) decreased in PCOS, whilst cathepsin D (p = 0.02) increased; however, linear regression showed that only cathepsins D and L and osteocalcin differed. Here, CLN5 is linked to polycystic ovary syndrome.