sialuria; sialic acid storage disorder; N-acetylneuraminic acid storage disease; Salla disease

Pathology

• free sialic acid accumulates in the cytoplasm
• gram quantities of neuraminic acid are secreted in urine
• metabolic defect involves lack of feedback inhibition of UDP-GlcNAc 2-epimerase by CMP-Neu5Ac, resulting in constitutive overproduction of free Neu5Ac
• enlarged lysosomes are seen on electron microscopic studies

Genetics

• associated in defects of gene for SLC17A5 autosomal recessive
• associated in defects of gene for GNE (autosomal dominant)

Clinical manifestations

• developmental delay
• coarse facial features
• hepatomegaly
• hypotonia
• cerebellar ataxia
• mental retardation
• symptoms generally present < 1 year of age
• progression is slow
• infantile sialuria is associated with non-immune hydrops fetalis

Laboratory

• gram quantities of neuraminic acid are found in urine
• SLC17A5 gene mutation

More general terms

• lysosomal storage disease

Additional terms

• UDP-GlcNAc-2-epimerase/ManAc kinase
• sialic acid; N-acetyl neuraminic acid (NANA)
• solute carrier family 17 member 5 (SLC17A5, sialin, Na+/sialic acid cotransporter, sodium phosphate cotransporter, AST, membrane glycoprotein HP59)

Database

• OMIM: https://mirror.omim.org/entry/269920
• OMIM: https://mirror.omim.org/entry/604369
• OMIM: https://mirror.omim.org/entry/269921