An autosomal dominant dopa-responsive dystonia in which the cause of the disease is a variation in the GCH1 gene. The disease is dystonia 5 (MONDO_0007495). Also known as: DYT-GCH1, Dopa-responsive dystonia, autosomal dominant, GTP cyclohydrolase 1-deficient dopa-responsive dystonia, Segawa Syndrome, Segawa syndrome, autosomal dominant, dystonia type 5, dystonia, DOPA-responsive, with or without hyperphenylalaninemia, dystonia, Dopa-responsive, autosomal dominant.