However, a large portion of the 25 pathways identified were affected by Sphk1 deficiency in SCD Berkeley mice, and the top three metabolic pathways affected by genetic deletion of Sphk1 in SCD mice were pentose phosphate pathway (PPP), glutathione metabolism, and sphingolipid metabolism (Fig. 2a). Here, SPHK1 is linked to Schnyder corneal dystrophy.