Background: Dopa-responsive dystonia (DRD) is associated with mutations of the GCH1. We first report four female siblings with DRD from one family, including three monozygotic triplets patients clinically and genetically.
Methods: We performed GCH1 analysis by direct sequencing of PCR product amplified with primers designed to cover the entire exons of GCH1 in those four patients and their mother.
Results: In all four patients with DRD, a new frameshift mutation (c.729delG; p.A190fsX191) was identified in the exon 5 of GCH1.
Conclusions: The frameshift mutation results in truncated GCH1 protein which is suspected to result in loss of function of the catalytic GTP-cyclohydrol domain.