Objective: To detect mutations of guanosine triphosphate cyclohydrolase I (GCH1) gene in Chinese patients with dopa responsive dystonia (DRD).
Methods: Six sporadic patients with DRD were examined. GCH1 gene mutations were detected using polymerase chain reaction (PCR), DNA sequence analysis and restriction enzyme digestion analysis. One hundred normal people were detected using PCR and restriction enzyme digestion analysis.
Results: A new point mutation, 151(G-->A) in exon one was found in a patient. It lead to substitution of a methionine for isoleucine at amino acid 1(M1I). This mutation was not found in normal control people.
Conclusion: The authors report a new heterozygotic point mutation 151(G-->A) in GCH1 gene. There are GCH1 gene mutations in Chinese sporadic patients with DRD.