ABCG2 and Schnyder corneal dystrophy: Kyoto Encyclopedia of Genes and Genomes function prediction shows that the top 10 metabolic functions of SCD patients were biosynthesis of amino acids, ABC transporters, carbon metabolism, ribosome, purine metabolism, pyrimidine metabolism and quorum sensing, two-component system, starch and sucrose metabolism, amino sugar and nucleotide sugar metabolism, amino sugar and nucleotide sugar metabolism.