ATP1A3 Gene

Rapid-onset dystonia parkinsonism is a rare movement disorder. "Rapid-onset" refers to the abrupt appearance of signs and symptoms over a period of hours to days. Dystonia is a condition characterized by involuntary, sustained muscle contractions. Parkinsonism can include tremors, unusually slow movement (bradykinesia), rigidity, an inability to hold the body upright and balanced (postural instability), and a shuffling walk that can cause recurrent falls.

Rapid-onset dystonia parkinsonism causes movement abnormalities that can make it difficult to walk, talk, and carry out other activities of daily life. In this disorder, dystonia affects the arms and legs, causing muscle cramping and spasms. Facial muscles are often affected, resulting in problems with speech and swallowing. The movement abnormalities associated with rapid-onset dystonia parkinsonism tend to begin near the top of the body and move downward, first affecting the facial muscles, then the arms, and finally the legs.

The signs and symptoms of rapid-onset dystonia parkinsonism most commonly appear in adolescence or young adulthood. In some affected individuals, signs and symptoms can be triggered by an infection, physical stress (such as prolonged exercise), emotional stress, or alcohol consumption. The signs and symptoms tend to stabilize within about a month, but they typically do not improve much after that. In some people with this condition, the movement abnormalities abruptly worsen during a second episode several years later.

Some people with rapid-onset dystonia parkinsonism have been diagnosed with anxiety, social phobias, depression, and seizures. It is unclear whether these disorders are related to the genetic changes that cause rapid-onset dystonia parkinsonism.

Alternating hemiplegia of childhood is a neurological condition characterized by recurrent episodes of temporary paralysis, often affecting one side of the body (hemiplegia). During some episodes, the paralysis alternates from one side of the body to the other or affects both sides at the same time. These episodes begin in infancy or early childhood, usually before 18 months of age, and the paralysis lasts from minutes to days.

In addition to paralysis, affected individuals can have sudden attacks of uncontrollable muscle activity; these can cause involuntary limb movements (choreoathetosis), muscle tensing (dystonia), movement of the eyes (nystagmus), or shortness of breath (dyspnea). People with alternating hemiplegia of childhood may also experience sudden redness and warmth (flushing) or unusual paleness (pallor) of the skin. These attacks can occur during or separately from episodes of hemiplegia.

The episodes of hemiplegia or uncontrolled movements can be triggered by certain factors, such as stress, extreme tiredness, cold temperatures, or bathing, although the trigger is not always known. A characteristic feature of alternating hemiplegia of childhood is that all symptoms disappear while the affected person is sleeping but can reappear shortly after awakening. The number and length of the episodes initially worsen throughout childhood but then begin to decrease over time. The uncontrollable muscle movements may disappear entirely, but the episodes of hemiplegia occur throughout life.

Alternating hemiplegia of childhood also causes mild to severe cognitive problems. Almost all affected individuals have some level of developmental delay and intellectual disability. Their cognitive functioning typically declines over time.