SLC19A3 and External ophthalmoplegia: Two apparently unrelated disease phenotypes, BBGD (MIM 607483) [10,11] and Wernicke's-like encephalopathy (MIM 606152) [12], have been shown to be associated with mutations of SLC19A3. Patients of BBGD with homozygous mutations (G23V, T422A) in SLC19A3 showed childhood-onset encephalopathy, characterized by epilepsy, confusion, external ophthalmoplegia, dysarthria, dysphagia, dystonia, rigidity and quadriparesis.