Predominantly occurs in females. Characterized by
postural and motor disturbances with marked diurnal fluctuation. Onset is
usually in early childhood presenting with lower limbs and axial dystonia, followed by
parkinsonism. Commonly the inversion and plantar flexion of feet can be seen early in
association with increasing flexion of the hip and the knee, resulting in a toe-walking
gait. Both flexor and extensor posture of the arms may occur. Posture reflex is impaired.
Slowly progressive parkinsonian features include slowed movement, muscle rigidity, and
balance difficulty. Symptoms are remarkable and are alleviated after sleep and aggravated
toward the evening. Response to a small dose of l-dopa is immediate and
most often associated with dramatic improvement. The coexistence of parkinsonian features
and the dramatic response to l-dopa distinguish this syndrome from other forms of
idiopathic torsion dystonia. The sustained nature of l-dopa
responsiveness and the lack of complications from therapy (including
wearing-off, “on-off” and unpredictable dose response) distinguish it from
other causes of childhood-onset parkinsonism.