GTR Home > Conditions/Phenotypes > Sialic acid storage disease, severe infantile type

Disease characteristics

Excerpted from the GeneReview: Free Sialic Acid Storage Disorders
The allelic disorders of free sialic acid metabolism — Salla disease, intermediate severe Salla disease, and infantile free sialic acid storage disease (ISSD) — are neurodegenerative disorders resulting from increased lysosomal storage of free sialic acid. The mildest phenotype is Salla disease, which is characterized by normal appearance and neurologic findings at birth followed by slowly progressive neurologic deterioration resulting in mild to moderate psychomotor retardation, spasticity, athetosis, and epileptic seizures. The most severe phenotype is ISSD, characterized by severe developmental delay, coarse facial features, hepatosplenomegaly, and cardiomegaly; death usually occurs in early childhood.

Available tests

8 tests are in the database for this condition. Compare labs offering these tests.

Check Associated genes for additional relevant tests.

Associated genes

  • Also known as: AST, ISSD, NSD, SD, SIALIN, SIASD, SLD, SLC17A5
    Summary: solute carrier family 17 (acidic sugar transporter), member 5

Clinical features

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  • Ascites
  • Cardiomegaly
  • Splenomegaly
  • Epicanthus
  • Vacuolated lymphocytes
  • Anteverted nares
  • Coarse facial features
  • J-shaped sella turcica
  • Conjugated hyperbilirubinemia
  • Metaphyseal irregularity
  • Seizure
  • Hydrocephalus
  • Nystagmus
  • Osteopenia
  • Premature birth
  • Failure to thrive
  • Nephrotic syndrome
  • Gingival overgrowth
  • High palate
  • Ptosis
  • Abnormality of the thorax
  • Hypopigmentation of the skin
  • Muscular hypotonia
  • Global developmental delay
  • Congestive heart failure
  • Abnormality of the foot
  • Hydrops fetalis
  • Cerebral atrophy
  • Hepatomegaly
  • Fair hair
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