Estimated occurrence4:1,000,000 inhabitants.
CauseDefect on the SLC17A5-gene on chromosome 6. The disease is inherited autosomal recessively. The transport of sialic acid from the lysosomes of the cells does not function as it should. Sialic acid thus accumulates in the cells and a greater amount is excreted in the urine. The disease implies that the myelin sheaths around the axons in the brain develop poorly. This probably causes impulses to propagate more slowly along the axon and results in neurological and motor symptoms.
General symptomsSymtoms appear during the first year of infancy as delayed motor development and low muscle tone (hypotonia). The children have difficulty in coordinating movement and maintaining balance (ataxia), and some present involuntary movements (athetosis) and/or intense reflexes in the legs (spasticity). Most individuals with Salla disease have severe intellectual disability. Some have epileptic seizures during adolescence, usually in the form of absence seizures. Spasticity in the legs and arms increases with age, motor activity deteriorates and some lose the ability to walk.
SynonymsSialic acid storage disorder, SIASD, Sialuria Finnish type
Orofacial/odontological symptomsNeurological impairment affects oral motor and speech development and difficulties with eating and drooling are common. Frontal open bite is a frequent finding.
Advice on follow-up and treatment
- Early contact with dental services for intensified prophylactic care and oral hygiene information is essential.
- Regular check-ups of dental and jaw development. Orthodontist should be consulted when needed.
- Speech, language and communication training are often required.
- Training in oral motor skills and extra stimulation in cases of eating disorders, speech difficulties and drooling may be relevant.
Updated: 2019-11-12 15:00