Two in the hand, an essential lesson in tremor management

Dopa responsive dystonia results from abnormalities in the dopamine synthesis pathway which produces an array of phenotypic presentations with equally numerous genotypes. First documented in children in 1971, the 'classic' phenotype is childhood onset, predominantly lower limb dystonia which gradually progresses to generalised dystonia. Other hallmarks of 'classical' dopa responsive dystonia include marked diurnal variation in symptom severity (worse in the evening), subsequent development of parkinsonism and an excellent, sustained response to levodopa. More recently, adult onset variants have been reported. Here we discuss two siblings with dopa responsive dystonia caused by a mutation in the GTP cyclohydrolase 1 gene. Both presented in adulthood with tremor rather than the 'classic' phenotype. A video is presented (available online) followed by a brief discussion of the literature.