SLC19A3 and Nystagmus: Recently, compound heterozygous mutations (E320Q, K44E) in SLC19A3 were shown to cause Wernicke's-like encephalopathy, which is characterized by acute onset of epilepsy, ataxia, nystagmus and ophthalmoplegia in the second decade of life, and symptoms are effectively alleviated with thiamin treatment [12].