Thiamine metabolism dysfunction syndrome (THMD) is a group of rare autosomal recessive encephalopathies caused by deficiencies of thiamine metabolism. Four genes, SLC19A3, SLC25A19, SLC19A2, and TPK1, are linked to this syndrome. Based on the defective genes and phenotypic traits, THMD is classified into five types. The clinical course of patients with THMD is usually progressive, leading to severe disability and even death if left untreated.
