This gene encodes the beta subunit of lysosomal acid phosphatase (LAP). LAP is chemically and genetically distinct from red cell acid phosphatase. The encoded protein belongs to a family of distinct isoenzymes which hydrolyze orthophosphoric monoesters to alcohol and phosphate. Mutations in this gene or in the related alpha subunit gene cause acid phosphatase deficiency. Multiple alternatively spliced transcript variants encoding different isoforms have been identified for this gene.