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Gene: PSAP

Green List (high evidence)

The PSAP gene encodes prosaposin, which is the precursor of four smaller proteins called saposin A, B, C, and D, which are produced when prosaposin is cleaved. Patients with two null alleles present with pSap deficiency and fatal infantile lysosomal storage disease. Patients with at least one allele with a mutation impairing only isolated saposins present with disorders resembling impairment of particular hydrolases. Defects of SapB result in metachromatic leukodystrophy.

Other phenotypes:
Mutations in PSAP that interfere with the function of the saposin C protein result in a disorder that resembles a severe form of Gaucher disease (Gaucher disease, atypical, MIM #610539, PMID: 31061751, 2514102). Signs and symptoms of this condition include neurological problems and hepatosplenomegaly.
Defects in SapA lead to atypical Krabbe disease, MIM #611722 (PMID: 15773042).
Combined SAP deficiency, MIM #611721 (PMID: 2514102, 11309366)

Created: 30 Dec 2024, 6:12 a.m. | Last Modified: 30 Dec 2024, 6:12 a.m.

Panel Version: 1.978

Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal

Phenotypes
Metachromatic leukodystrophy due to SAP-b deficiency, MIM #249900

Publications

• PMID: 10682309
• 30632081
• 11309366
• 19267410
• 8554069