Sammanfattning
BACKGROUND: Dopa-response dystonia is the collective term for a group of highly treatable disorders that are characterised by altered neurotransmitter levels. Increased insight into the underlying pathophysiology has improved understanding of these disorders.
METHOD: This article is based on 39 articles identified through a systematic search of the Medline database, two websites and a textbook.
RESULTS: Dopa-responsive dystonia usually has onset in childhood or adolescence and gives rise to motor, cognitive, psychiatric and/or autonomic symptoms and findings. These may be non-specific and are easily misinterpreted as reflecting other neurological disorders. Dopa-responsive dystonia is caused by monogenic mutations and shows autosomal recessive or dominant inheritance. Pathogenic variants have been identified in three genes: guanosine triphosphate (GTP) cyclohydrolase 1, sepiapterin reductase and tyrosine hydroxylase. The pathogenic variants lead to enzyme deficiencies and give rise to early-onset dystonia, which responds well to levodopa. A precise diagnosis is made by determining levels of pterins, biogenic monoamines and their metabolites in the cerebrospinal fluid, and by genetic testing.
INTERPRETATION: Current knowledge is based on case reports and small patient datasets, which show that this patient population benefits greatly from levodopa. Diagnosis has become easier in recent years due to modern biochemical and molecular genetic analyses. The current scientific literature gives reason to believe that there may be undiagnosed patients in Norway with dopa-responsive dystonia.