Recognizing atypical involuntary movements in childhood autosomal recessive ataxia syndromes can lead to early diagnosis and may allow for more effective treatment of the symptoms, according to a recent review of emerging data.
Autosomal recessive cerebellar ataxias (ARCA) are a diverse group of rare, usually inherited conditions that typically appear before age 20.
ARCA are primarily defined by progressively abnormal movement coordination (ataxia) that involve the central and peripheral nervous systems. In some cases, involuntary abnormal movements are the first symptoms of ARCA.
The review paper “More Than Ataxia: Hyperkinetic Movement Disorders in Childhood Autosomal Recessive Ataxia Syndromes,” published in the journal Tremor and Other Hyperkinetic Movements, sheds light on involuntary movements associated with some specific ARCA syndromes, particularly ataxia-telangiectasia (A-T), ataxia with oculomotor apraxia types 1 and 2 (AOA1 and AOA2), Friedreich’s ataxia (FA), and ataxia with vitamin E deficiency (AVED).
Review author Toni S. Pearson of the Department of Neurology at Washington University School of Medicine in St. Louis, Missouri, noted that involuntary movements are more frequent in the majority of A-T and AOA1 patients, and less frequent in AOA2, FA, and AVED patients.
Patients with ARCA can experience hyperkinetic movement disorders that include dystonia (abnormal muscle tone leading to spasms and abnormal posture), chorea (jerky involuntary movements), myoclonus (spasmodic, jerky muscle contractions), and tremor. The severity of the involuntary movement disorders can range from mild to severe.
“Recognition of hyperkinetic movement disorders in these diseases has important implications for diagnosis, genetic counseling, and treatment,” Pearson wrote.
The type of hyperkinetic movement disorders exhibited seemed to be associated specifically with the ARCA syndrome endured by the patient. More specifically, the author reported that patients with A-T and AVED have a higher frequency of dystonia or dystonia with myoclonus, while generalized chorea was shown to be more frequent in patients with AOA1 or A-T.
“When movement symptoms are severe and functionally disabling, accurate characterization is also important for treatment. In contrast to the functional deficits resulting from cerebellar degeneration and motor neuropathy, involuntary movements are often amenable to symptomatic treatment,” the author wrote.