 Mutations in this gene and the deficiency in alpha-N-acetylgalactosaminidase activity have been identified as the cause of Schindler disease.Enzymes with this activity is useful for converting type A blood to type O, giving it the name of A-zyme.Bacterial enzymes in the GH109 family, including the A-zyme from "Elizabethkingia meningoseptica", runs this reaction efficiently.