Free sialic acid storage disease

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Free sialic acid storage disease

ORPHA:834Disease

Also called FSASD · Free sialic acid storage disorder

What it is

A rare lysosomal storage disease characterized by a spectrum of clinical manifestations including neurological and developmental disorders with a severity ranging from the milder form, also called Salla disease (SD), to the most severe phenotype, also called infantile free sialic acid storage disease (ISSD).

Key facts

Prevalence
<1 / 1 000 000
Age of onset
Antenatal, Infancy, Neonatal
Inheritance
Autosomal recessive
Classified as
Disease

Prevalence figures describe populations, not individuals, and are often estimates from a single study. Where the figure is an incidence or a birth prevalence, it says so.

Signs and symptoms

These ranges are how often a sign appears across everyone diagnosed, not a prediction for one person — most people have some of these and not others. Orphanet also records findings that are specifically absent in this disease; those are in the data but not listed here.

Genes reported in subtypes

SLC17A5

Orphanet records this gene on 3 more specific entries under this disorder, not on this entry itself:

A well-studied disease is usually split into subtypes, and the gene is curated on whichever one the evidence belongs to. Open a subtype to see which gene goes with it.

ICD-10 codes

E77.8filed under a broader ICD-10 category — shared with 56 other rare diseases

ICD-10 has no distinct code for most rare diseases, so many are filed under the nearest available one. A shared code identifies the group, not this disease — the ORPHAcode above is what identifies it.

Related health topics

Reached through the ICD-10 categories this disease is filed under, so these describe the broader group rather than this disease specifically.

Cross-references

GARD 10870MESH C538523MONDO 0019366OMIM 269920OMIM 604369UMLS C2931872

Orphadata Science: Free access data from Orphanet. © INSERM 1999. Data version 2026-06-23. Available under CC BY 4.0. This is a reference, not medical advice.

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