Blockage of the Leloir pathway by GALE deficiency or dysfunction activates alternate pathways of glucose metabolism and leads to galactitol and galactonate formation. Galactonate is metabolized by the pentose phosphate pathway, and is not considered toxic.[12] Galactitol, however, may accumulate in lens fibers, perturbing lens epithelial cell permeability and leading to cell death and cataract formation.[13] GALE deficiency also perturbs glycolipid and glycoprotein biosynthesis due to decreased production of UDP-GalNAc from UDP-GlcNAc.[3]