Thiamine 1 (vitaminB1) is essential for energy metabolism, and its deficiencyleads to neurological disorders.1−3 Thiamine, being positively charged,requires transport into the cytoplasm, where it is converted intocoenzyme thiamine diphosphate (ThDP) 2a by thiamine pyrophosphokinase(TPK) (Figure 1A).1−5 ThDP-dependent enzymes include pyruvate dehydrogenase complex E1-subunit(PDHc E1), pyruvate decarboxylase (PDC), oxoglutarate dehydrogenasecomplex E1-subunit (OGDHc E1), pyruvate oxidase (PO), and transketolase(TK). The gene discussed is TKT; the disease is nervous system disorder.