What is (are) Dopa-responsive dystonia ?
Dopa-responsive dystonia (DRD) is an inherited type of dystonia that typically begins during childhood but may begin in adolescence or adulthood. Depending on the specific type of DRD, specific symptoms can vary. Features can range from mild to severe. In most cases, dystonia begins in the lower limbs and spreads to the upper limbs over time. Symptoms may include unusual limb positioning; a lack of coordination when walking or running; sleep problems; and episodes of depression. Affected people also often develop a group of movement abnormalities called parkinsonism. Although movement difficulties usually worsen with age, they often stabilize around age 30. DRD may be caused by mutations in the GCH1, TH or SPR genes, or the cause may be unknown. Depending on the genetic cause, DRD may be inherited in an autosomal dominant (most commonly) or autosomal recessive manner. This form of dystonia is called 'dopa-responsive' dystonia because the symptoms typically improve during treatment with levodopa and carbidopa.