Table 2.

Select Features of Free Sialic Acid Storage Disorders

Feature 1% of Persons w/Feature
Developmental delay / cognitive impairment75%
Facial dysmorphism / coarse facies 250%-68% 2
Hepatosplenomegaly54%
Truncal hypotonia54%
Skeletal abnormalities50%
Spasticity48%
Ataxia44%
Failure to thrive42%
Short stature27%
Hydrops fetalis24%
Epilepsy22%
Neurodegenerative course20%
Neonatal ascites19%
Cardiomegaly19%
Hernias19%
Microcephaly18%
Recurrent airway infections16%
Nystagmus12%
Nephropathy10%
Optic atrophy7%
Athetosis6%
Ptosis3%
Hoarse voice2%
Corneal clouding1%
Brain MRI findingsBrain atrophy23%
Hypomyelination22%
Hypoplasia of the corpus callosum16%
1.

Includes features reported in entire spectrum of phenotype (less severe to severe FSASD)

2.

Coarse facies are more frequent in severe FSASD.

From: Free Sialic Acid Storage Disorders

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