P4HA2 was identified as a novel causative gene for nonsyndromic high myopia.P4HA2 mutations may lead to myopic axial elongation of eyeball as a consequence of quantitative and structural alterations of collagen.P4HA2 was dramatically augmented in liver samples of HBV transgenic mice, clinical liver cirrhosis and liver cancer patients. Functionally, HBx-elevated P4HA2 enhanced the collagen deposition in the liver in vivo and in vitro, leading to liver fibrosis and liver cancer progression.