SLC1A4 and Spastic tetraplegia: SLC1A4 mutations are associated with a rare autosomal recessive neurodevelopmental disorder characterized by spastic tetraplegia, thin corpus callosum and progressive microcephaly,64 associated with delayed myelination.65 Downregulation of SLC1A4 protein levels in astrocytes from brain white matter has been associated with acute multiple sclerosis.66