The patients with severe form show intractable epilepsy and brain atrophy on MRI since early infancy. These patients showed spastic quadriplegia with severe developmental delay and infantile spasms. Early childhood death was also reported in severe patients. The patients with milder form manifest complex phenotypes with less severe developmental delay with or without childhood-onset epilepsy. The other group shows spastic paraplegia and ataxia.
SPTAN1