Table 2

Thiamine responsive diseases

	Pathogenesis	Neurological symptoms	Other symptoms
Acquired diseases resulting from thiamine deficiency
Beriberi	Endemic in Asia, owing to the low thiamine content of polished rice	Sensorimotor neuropathy, hypacusis, optic neuritis, cranial nerve lesions	Hoarseness, incontinence, cardiovascular decompensation
Neuropathy	Chronic alcoholism with malnutrition, anorexia nervosa, parenteral nutrition, intestinal diseases	Sensorimotor neuropathy
Wernicke's encephalopathy	Chronic alcoholism with malnutrition, anorexia nervosa, parenteral nutrition, intestinal diseases	Eye muscle and gaze paresis, nystagmus, pupillary dysfunction, vegetative dysregulation, seizures, confusion, apathy, coma
Korsakow's syndrome	Chronic alcoholism with malnutrition, anorexia nervosa, parenteral nutrition, intestinal diseases	Loss of short term and long term memory

Inherited diseases resulting from defects of thiamine transport
TRMA	Autosomal recessive; mutations in the thiamine transporter gene	Megaloblastic anaemia, diabetes and deafness, abnormalities of the retina and the optic nerve, stroke-like episodes	Congenital heart disease, arrythmias, aminoaciduria, situs inversus
Inherited diseases resulting from defects of thiamine dependent enzymes
Leigh syndrome (subgroup)	Mutations in PDHCgenes	Ophthalmoplegia, nystagmus, ataxia, dystonia, optic atrophy, seizures, myoclonus, neuropathy, psychomotor retardation	Failure to thrive, respiratory insufficiency
Maple syrup urine disease (subgroup)	Mutations in BCKDgenes	Acute episodes with vomiting, lethargy or coma, seizures, mental and physical retardation	Maple syrup urine odour
KGDH deficiency	Mutations in KGDHgenes	Hypotonia and neurological deterioration, death in childhood	Metabolic acidosis, hyperlactataemia
Predisposition to Wernicke's encephalopathy	Mutations inTK genes

PDHC = pyruvate dehydrogenase complex.
BCKD = branched chain alpha ketoacid dehydrogenase.
KGDH = ketoglutarate dehydrogenase.
TK = transketolase.