[Hereditary progressive dystonia with marked diurnal fluctuation--a report of two siblings, one of them showing age-dependent changes of symptoms].

Two siblings of hereditary progressive dystonia with marked diurnal fluctuation are reported in this communication. The case 1 is a 50-year-old woman who developed dystonia in the right lower extremity at the age of 8 which deteriorated in the afternoon. At the age of 13 she became unable to walk in the afternoon because of dystonia, but after the age of 23 her symptoms began to ameliorate and at the age of 29 her daily activities became no longer disturbed by dystonia even in the evening. However, at the age of 42 dystonia in the lower extremities began to worsen again toward the end of the day and after the age of 47 dystonia appeared in the all extremities. Since the age of 49 she had been able to walk only for three hours after awakening. Her 37-year-old half sister, case 2, also developed a slight dystonia in the left upper extremity at the age of 8. At the age of 33 she felt tight in the neck, waist and extremities after hard works in the evening, and the worst of it was in the left arm which would not move. Both cases were well responsive to L-dopa. Their family history revealed that their father had a history of dystonia the course of which was similar to that of the case 1. Dominant inheritance could be considered in this family. These findings would suggest that hereditary progressive dystonia with marked diurnal fluctuation could show not only a diurnal fluctuation but also age-dependent changes of symptoms. Its basic abnormalities might exist in the dopamine storage pool.