This gene encodes one of several enzymes involved in the lysosomal degradation of heparan sulfate. Mutations in this gene are associated with Sanfilippo syndrome A, one type of the lysosomal storage disease mucopolysaccaridosis III, which results from impaired degradation of heparan sulfate. Transcripts of varying sizes have been reported but their biological validity has not been determined. [provided by RefSeq, Jul 2008].