Epilepsy syndrome, infantile-onset symptomatic
GM3 Synthase Deficiency, Infantile-onset symptomatic epilepsy syndrome - developmental stagnation - blindness, Amish Infantile Epilepsy Syndrome, ST3GAL5-CDG, Salt and pepper syndrome
Type of disease: Rare Condition or Disease
GM3 synthase deficiency is a rare neurological disorder in which the brain does not develop normally. Symptoms of the disease begin within the first weeks or months of life and include difficulty feeding, irritability, vomiting, and seizures accompanied by loss of consciousness (grand mal seizures). Vision and hearing loss, spots of darker skin color (hyperpigmentation), and intellectual and developmental delays develop as the disease progresses. GM3 synthase deficiency is a congenital disorder of glycosylation and includes both cases described as Amish infantile epilepsy syndrome and cases described as salt & pepper syndrome.
GM3 synthase deficiency is caused by a mutation in the ST3GAL5 gene and is inherited in an autosomal recessive manner. The ST3GAL5 gene tells the body to make an enzyme that supports gangliosides, which are molecules that are important for brain development and function.
GM3 synthase deficiency is suspected when a child presents with symptoms characteristic of the disease. Genetic testing confirms the diagnosis. Treatment is focused on relieving symptoms of the disease, which may include nutritional and feeding support and medications to lessen the severity of seizures. Although there is no cure for the condition, children with GM3 synthase deficiency have lived into early adulthood.