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September 1991

Clinical and Genetic Analysis of Progressive Dystonia With Diurnal Variation

Author Affiliations

From the Department of Neurology, University of Michigan, Ann Arbor (Dr Fink); the Developmental and Metabolic Neurology Branch (Drs Filling-Katz and Argoff) and the Medical Neurology Branch (Dr Hallett), National Institute of Neurologic Disorders and Stroke, National Institutes of Health, Bethesda Md; and the Department of Neurology, University of Massachusetts, Worcester (Dr Ravin).

Arch Neurol. 1991;48(9):908-911. doi:10.1001/archneur.1991.00530210034019

• We examined 17 patients with progressive dystonia with diurnal variation, a dominantly inherited, generalized dystonia that begins in childhood. Dystonia was typically least severe in the morning, increased as the day continued, and markedly improved with low doses of carbidopa-levodopa. We also studied the patient's parents, children, and siblings from seven families. We observed a spectrum of neurologic involvement, phenotypic variability among siblings, and incomplete genetic penetrance. Progression of motor impairment over several years, which reaches a plateau during late adolescence, is useful in distinguishing progressive dystonia with diurnal variation from cerebral palsy and degenerative disorders. It is important to recognize the subtle, as well the extreme, manifestations of progressive dystonia with diurnal variation because it is treatable. Genetic counseling must consider that mildly affected parents with little or no disability may have profoundly affected children. Appreciation of the phenotypic variability and degree of genetic penetrance will permit detailed genetic and biochemical analyses.