Sialic Acid Storage Disease | Symptoms & Causes
What are the symptoms of sialic acid storage disease?
Manifestations of sialic acid storage disease can vary significantly depending on the subtype of the disease a child has. Features of infantile free sialic acid storage disease (ISSD) appear immediately or shortly after birth and progress more rapidly than symptoms in other subtypes. Children diagnosed with Salla disease or intermediate severe Salla disease typically develop symptoms in the first year of life.
Signs and symptoms include:
- Poor muscle tone (hypotonia)
- Enlarged organs (organomegaly)
- Failure to gain weight and length (failure to thrive)
- Distinct facial features (coarse facial features)
- Seizures
- Intellectual disability
- Bone malformations
- Difficulty with movement and balance (ataxia)
- Abnormal tensing of muscles (spasticity)
- Involuntary writhing movements of the limbs (athetosis)
What causes sialic acid storage disease in children?
In all three subtypes of sialic acid storage disease, a genetic variation in the gene known as SLC17A5 results in the dysfunction of a specialized protein known as sialin. Sialin is located in the lysosomes of cells. Under normal conditions, this protein helps to remove sialic acid produced during the breakdown of certain fats and proteins from the lysosomes and transport it to other parts of the cell. In individuals with sialic acid storage disease, dysfunctional sialin prevents the removal of sialic acid from the lysosomes, resulting in an abnormal accumulation of the substance which eventually causes signs and symptoms of disease.
Sialic acid storage disease is inherited in an autosomal recessive pattern, which means that an affected child has received one defective copy of the SLC17A5 gene from each of their parents.
Sialic Acid Storage Disease | Diagnosis & Treatments
How do we treat sialic acid storage disease?
There are currently no approved therapies to reverse the effects of any subtype of multiple sialic acid storage disease. Current approaches to sialic acid storage disease involve interdisciplinary collaboration to provide supportive therapies and targeted management for specific symptoms.
How we care for sialic acid storage disease
At the Boston Children’s Lysosomal Storage Disorders (BoLD) Program, our team of providers is committed to the care of complex patients. As part of Boston Children’s Hospital, we are prepared to meet the challenge of providing multifaceted care by partnering with you and your child to deliver direct care in our BoLD clinic. We work with the broad array of world-class specialists at Boston Children’s to optimize the care we provide your child with sialic acid storage disease.
