Reply: Infantile Leigh-like syndrome caused by SLC19A3 mutations is a treatable disease

Sir, The letter by Haack et al. (2014) provides important information confirming the role of the thiamine transporter hTHTR2 in Leigh syndrome and the beneficial effect of biotin and/or thiamine treatment for patients harbouring mutations in the gene encoding hTHTR2, SLC19A3 . In recent years many new pathogenic mutations have been reported in SLC19A3 resulting in several age-related neurological phenotypes like biotin-responsive basal ganglia disease (BBGD), Wernicke-like encephalopathy and Leigh syndrome and various responses to biotin and/or thiamine (Zeng et al. , 2005; Kono et al. , 2009; Debs et al. , 2010; Yamada et al. , 2010). The exact mechanism by which biotin and/or thiamine treatment results in alleviation of the phenotype or prevents further disease progression is still unclear, but the current data challenge the initial hypothesis that biotin-induced overexpression is the central mechanism. Table 1 summarizes all pathogenic mutations identified in SLC19A3 to date, the …