Treatment of homocystinuria-related dystonia with deep brain stimulation: a case report.

A 23-year-old woman with the medical history of homocystinuria that had been diagnosed at the age of 14 has been non-responsive to treatment. The patient presented with the symptoms of dysphonia, dysarthria and severe dystonia of the neck and left extremities. Blood and urine biochemistry revealed high levels of homocystine. Brain magnetic resonance imaging was normal with no detectable pathologies. Medical treatment strategies were used and repeated injections of botulinum toxin A were administered, but the symptoms showed no significant improvement. The patient was then operated, and deep brain stimulators targeting the bilateral globus pallidus internus were implanted. After the activation of the electrodes, dystonia symptoms showed a remarkable improvement. Good outcome was documented during the follow-up period of 7 months. To our best knowledge, this is the first reported case of homocystinuria-related dystonia symptoms that were successfully treated with deep brain stimulation.