Congenital cataracts are typically caused by mutations in genes encoding lens regulatory (e.g. FOXE3, HSF4, MAF, PAX6 and PITX3) and structural (e.g. crystallins, connexins, MIP, BFSP2, EPHA2, EPHA5 and LIM2) proteins (see Shiels and Hejtmancik, 2013). The gene discussed is MIP; the disease is early-onset non-syndromic cataract.