[2][1] First described in 1998[6] and then genetically distinguished in 2005,[7] the disease is characterized by progressive brain damage that, if left untreated, can lead to coma and/or death.
Additional observed symptoms include spasticity or cogwheel rigidity, seizures, difficulty swallowing (dysphagia), ataxia, slurred speech (dysarthria), ophthalmoplegia, opisthotonus, facial palsy, confusion, hyperreflexia, Babinski responses, and ankle clonus.
[1][5] It is characterized by ataxia, ophthalmoplegia, double vision (diplopia), rapid and uncontrollable eye movement (nystagmus), status seizures, and droopy eyelid (ptosis).
[4] Episodes of symptoms can be triggered by several things:[5] BTBGD can be diagnosed based on brain imaging and confirmed with genetic testing.
[9] Additional diagnostic tools include laboratory testing of biological fluids and reviewing autosomal recessive inheritance in the family history.
[citation needed] The MRI of individuals with BTBGD may reveal lesions on the basal ganglia and central bilateral necrosis in the caudate nucleus and putamen.
[5] Additional MRI findings include high T2 signal intensity with possible swelling in basal ganglia, and abnormal diffuse involvement of the subcortical white matter, cortical, and infratentorial brain.
[5] Genetic testing of family members allows for the identification of subtle symptoms, asymptomatic carriers, and increased-risk individuals, which allows for early treatment as needed.