Atypical presentation of dopa-responsive dystonia in Taiwan

Abstract

The typical clinical presentation of dopa-responsive dystonia, which is also called Segawa disease, is a young age of onset, with predominance in females, diurnal fluctuation of lower limb dystonia, and fair response to low-dose levodopa. This disease has both autosomal dominant and autosomal recessive inheritance. Autosomal dominant Segawa disease is caused by GCH1 mutation on chromosome 14q22.1-q22.2. Here, we report the case of a male patient with genetically confirmed Segawa disease and atypical presentations including no diurnal symptom fluctuation and insufficient response to levodopa. The patient's father who had the same mutation presented parkinsonism in old age. We also review the literature to address the broad clinical heterogeneity of Segawa disease and the influence of onset age on clinical presentation.

Keywords: Segawa disease; atypical presentation; dopa‐responsive dystonia; onset age; parkinsonian.

Figure 1

Pedigree of the study family. A genetic study was performed for the index case (arrow) and his father. Black indicates positive clinical signs; gray indicates suspicious clinical symptoms. Patient with parkinsosian symptoms was indicated with horizontal line symbol and patient with dystonia symptoms was indicated with dotted symbol

Figure 2

Image of 99mTc‐TRODAT‐1 SPECT of index patient. The image revealed bilateral symmetry of the normally shaped caudate nucleus and putamen. Symmetrical distribution of dopaminergic radioactivity was noted in the striatum. The result revealed no presynaptic uptake decreasing

Figure 3

Genetic study of the patient. A mutation was noted at exon 6 c.670 A>G