Also known as thiamine transporter 2 deficiency or thiamine metabolism dysfunction syndrome 2 (THMD2), BTBGD results from mutations in the solute carrier family 19, member 3 (SLC19A3, MIM: 6,06,152) gene, which encodes for the thiamine transporter 2 (THTR-2). This evidence concerns the gene SLC19A3 and biotin-responsive basal ganglia disease.