Dystonia syndromes have a remarkable degree of phenotypic variability with frequent overlap among different syndromes. There is no pathognomonic presentation that allows for reliable clinical-etiological correlations, either for genetic or for environmental forms1.

While identifying a specific form of dystonia solely on clinical grounds is often difficult if not impossible, careful observation of the phenotypic expression of the dystonia itself, of any associated features and ‘‘red flags,’’ and of the disease course, may provide helpful hints with respect to the correct classification of the dystonia, which is the first and critical step toward establishing its aetiology13.

As the number of dystonia syndromes and recognized aetiologies has grown, the diagnostic approach has become increasingly challenging. A “shotgun” approach that involves testing for all potential disorders is usually not suitable. Diagnostic testing can be guided by a strategy that involves a syndromic approach14,12.

Briefly, the syndromic approach involves classifying patients according to accompanying clinical features and tailoring the diagnostic studies to that syndrome2: