Alpha-N-acetylgalactosaminidase (NAGA) deficiency type 3 is a rare clinically heterogeneous type of NAGA deficiency with developmental, neurologic and psychiatric manifestations presenting at an intermediate age. The disease is Monarch Disease Ontology id MONDO_0019264 (alpha-N-acetylgalactosaminidase deficiency type 3). Also known as: NAGA deficiency type 3, Schindler disease type 3.