Free sialic acid storage disease

Abstract

Free sialic acid storage disease (FSASD) is an autosomal recessive inherited multisystem neurodegenerative lysosomal storage disease (LSD) due to bi-allelic mutations in the membrane exporter SLC17A5. This gene encodes the lysosomal trans membrane protein SLC17A5 also called sialin. Mutation of this protein causes accumulation of free sialic acid and glucuronic acid in the lysosomes and other organs. The clinical manifestations of FSASD include severe organs enlargements, coarse facial features, and neurodegenerative symptoms characterized by muscular hypotonia, cerebellar ataxia, and cognitive impairment. Increased urinary excretion of free sialic acid (FSA) above normal is also noticed in FSASD. This chapter summarizes the disease' classification and clinical manifestations, epidemiology, pathophysiology, available treatments and future investigational options.