Monarch Disease Ontology term MONDO_0017779 (alpha-N-acetylgalactosaminidase deficiency) can be described as follows. Alpha-N-acetylgalactosaminidase (NAGA) deficiency is a very rare lysosomal storage disease that is clinically and pathologically heterogeneous and is characterized by deficient NAGA activity. Also known as: NAGA deficiency, Schindler disease, alpha-N-acetylgalactosaminidase activity disease, disorder of alpha-N-acetylgalactosaminidase activity.