Dopa-responsive dystonia (DRD) is a complex genetic disorder with either autosomal dominant or autosomal recessive inheritance, with autosomal dominant being more frequent. Autosomal dominant DRD is known to be caused by mutations in the GCH1 gene, with incomplete penetrance frequently reported, particularly in males. Here, we report a male patient with DRD caused by exon 1 deletion in the GCH1 gene inherited from the asymptomatic mother. The patient had an atypical presentation, notably with no dystonia, and underwent extensive workup for a myriad of neuromuscular disorders before a low-dose L-dopa trial and confirmatory genetic testing were performed. Our experience with this family highlights an atypical presentation of DRD and prompts us to consider the genetic complexity of DRD.
Keywords: Dopa-responsive dystonia; GCH1 gene; Levodopa.