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IEMbase 0267: SLC17A5-related Sialin deficiency, severe

Scope

Field Value
IEMbase ID 267
Nosology 3.6.02.01
Gene SLC17A5
External IDs OMIM:269920; ORPHA:309334
Generated mapping AMBIGUOUS; Free_Sialic_Acid_Storage_Disease.yaml#Salla Disease and Salla_Disease.yaml
Candidate DisMech targets Free_Sialic_Acid_Storage_Disease.yaml#Infantile Free Sialic Acid Storage Disease; Salla_Disease.yaml
Review date 2026-07-07

IEMbase phenotype signal

IEMbase represents this as severe SLC17A5-related sialin deficiency, with alternate labels infantile sialic acid storage disease, Salla disease, and ISSD. The record is autosomal recessive and treatability is marked unknown, with no treatment rows in the cached JSON.

Biochemical rows include increased urinary N-acetylneuraminic acid in the neonatal, infancy, and childhood periods. Clinical rows include ataxia, distal phalanges hypoplasia, fetal hydrops, growth retardation, hip dysplasia, hypotonia, nystagmus, skeletal abnormalities, and widened metaphyses of the elbows and knees.

DisMech phenotype coverage

Free_Sialic_Acid_Storage_Disease.yaml#Infantile Free Sialic Acid Storage Disease is the best canonical target. The local umbrella entry represents the SLC17A5/FSASD severity spectrum and explicitly includes the severe infantile subtype, historically called infantile free sialic acid storage disease or ISSD. It covers impaired sialin-mediated lysosomal export, free N-acetylneuraminic acid accumulation, increased free sialic acid, severe developmental delay, coarse facial features, hepatosplenomegaly, cardiomegaly, early mortality, fetal hydrops, hypotonia, ataxia, nystagmus, seizures, white matter disease, genetic testing, supportive care, genetic counseling, and investigational base editing.

Salla_Disease.yaml is useful secondary context for the milder classic Salla end of the same spectrum, but it is not the best canonical target for this severe/ISSD IEMbase record.

Concordance and completeness

Judgement: generated ambiguity should resolve to the FSASD umbrella's infantile subtype, not to standalone classic Salla disease.

IEMbase and DisMech agree on SLC17A5/sialin identity, autosomal recessive inheritance, free sialic acid/N-acetylneuraminic acid accumulation, severe infantile disease framing, fetal hydrops, hypotonia, ataxia, and nystagmus. IEMbase adds skeletal specificity for distal phalangeal hypoplasia, hip dysplasia, widened metaphyses, growth retardation, and skeletal abnormalities. DisMech is richer for mechanism, severity spectrum, neurodevelopmental course, visceral/cardiac features, and treatment/reproductive counseling context.

Curation actions

  • Resolve this record to Free_Sialic_Acid_Storage_Disease.yaml#Infantile Free Sialic Acid Storage Disease.
  • Keep Salla_Disease.yaml as secondary spectrum context only.
  • Use IEMbase's skeletal and growth rows as enrichment prompts for the severe infantile FSASD subtype.