Dopa-responsive dystonia

Dopa-responsive dystonia is a disorder that involves involuntary muscle contractions, tremors, and other uncontrolled movements (dystonia). The features of this condition range from mild to severe. This form of dystonia is called dopa-responsive dystonia because the signs and symptoms typically improve with sustained use of a medication known as L-Dopa.

Signs and symptoms of dopa-responsive dystonia usually appear during childhood, most commonly around age 6. The first signs of the condition are typically the development of inward- and upward-turning feet (clubfeet) and dystonia in the lower limbs. The dystonia spreads to the upper limbs over time; beginning in adolescence, the whole body is typically involved. Affected individuals may have unusual limb positioning and a lack of coordination when walking or running. Some people with this condition have sleep problems or episodes of depression more frequently than would normally be expected.

Over time, affected individuals often develop a group of movement abnormalities called parkinsonism. These abnormalities include unusually slow movement (bradykinesia), muscle rigidity, tremors, and an inability to hold the body upright and balanced (postural instability).

The movement difficulties associated with dopa-responsive dystonia usually worsen with age but stabilize around age 30. A characteristic feature of dopa-responsive dystonia is worsening of movement problems later in the day and an improvement of symptoms in the morning, after sleep (diurnal fluctuation).

Rarely, the movement problems associated with dopa-responsive dystonia do not appear until adulthood. In these adult-onset cases, parkinsonism usually develops before dystonia, and movement problems are slow to worsen and do not show diurnal fluctuations.