Autosomal recessive dopa-responsive dystonia (DRD) is a rare inherited neurological disorder that is characterized by dystonia, a movement disorder that causes involuntary muscle contractions and abnormal postures. It is caused by a mutation in the GCH1 gene, which is responsible for producing the enzyme GTP cyclohydrolase 1. This enzyme is necessary for the production of the neurotransmitter dopamine, which is important for controlling movement. Symptoms of DRD usually begin in childhood and can include difficulty walking, tremors, and muscle stiffness. Treatment typically involves taking levodopa, a medication that helps to increase dopamine levels in the brain.