General description

Biotin-thiamine-responsive basal ganglia disease (BTBGD) is a rare autosomal recessive neurometabolic disorder caused by a mutation in the SLC19A3 gene, which encodes thiamine transporter. This mutation leads to impaired transportation and absorption of thiamine. The condition is treatable with biotin and thiamine, and its symptoms typically present at any age, most commonly in childhood between 3 and 10 years, but also in early infancy or adulthood.

Clinical Presentations

1. Early infancy: This presentation resembles a Leigh syndrome or atypical infantile spasms, appearing within the first three months of life. Symptoms include acute encephalopathy, poor feeding, vomiting, and severe lactic acidosis.
2. Childhood onset (age 3-10): Typical presentations include recurrent episodes of subacute encephalopathy, characterized by confusion, seizures, ataxia, dystonia, supranuclear facial palsy, ophthalmoplegia, and/or dysphagia. Common neurological signs include dystonia, cogwheel rigidity, hyperreflexia, ankle clonus, and Babinski responses. Hemiparesis or quadriparesis may occur. Episodes are often triggered by fever, minor trauma, or stress, and anti-seizure medications typically control seizures.
3. Adult-onset: In the second decade of life, the condition may present as a Wernicke encephalopathy-like episode, characterized by status epilepticus, ataxia, nystagmus, diplopia, ophthalmoplegia, and ptosis.