Biotin or Thiamine Responsive Basal Ganglia Disease (Thiamine Metabolism Dysfunction 2, Biotin or Thiamine Responsive Encephalopathy Type 2, THMD2)

Synonyms: Thiamine Metabolism Dysfunction 2, Biotin or Thiamine Responsive Encephalopathy Type 2, THMD2

Chromosome: 2q36.3

Gene: SLC19A3

Protein: thiamine transporter 2

Inheritance: autosomal recessive

Patients present with neurologic symptoms that respond to oral biotin and/or thiamine.

Syndromes:

(1) early infantile

(2) classic childhood

(3) adult-onset

Infantile:

(1) infantile spasms

(2) poor feeding

(3) vomiting

(4) acute encephalopathy

(5) severe lactic acidosis

Classic childhood:

(1) recurrent subacute encephalopathy with altered level of consciousness

(2) dystonia

(3) cogwheel rigidity

(4) seizures

(5) episodes triggered by febrile illness, stress or trauma

(6) bilateral lesions of the basal ganglia

Early adult-onset encephalopathy (Wernicke-like)

(1) status epilepticus

(2) ataxia

(3) nystagmus

(4) diplopia

(5) ophthalmoplegia