Genetic Analysis Of CHCHD2 Gene In Chinese Patients With Parkinson Disease And Essential Tremor

Background:Parkinson disease and essential tremor are common neurodegenerative disorders.5%-10%of Parkinson disease patients show an autosomal dominant or recessive mode of inheritance and 50%-70%of essential tremor patients have a positive family history,which indicates that genetic factors play an important role in the mechanism of the two disorders.Recently,Funayama et al.identified CHCHD2 gene as a novel causative gene of autosomal dominant Parkinson disease.What’s more,they identified CHCHD2 mutations not only in patients with Parkinson disease,but also in a patient with essential tremor from the same family.Larger-scale genetic studies in multiple ethnic populations need to be performed to establish CHCHD2 gene associations with Parkinson disease and essential tremor.Objective:1.To clarify the relationship between CHCHD2 gene and Chinese patients with Parkinson disease.2.To clarify the relationship between CHCHD2 gene and Chinese patients with essential tremor.Methods:The study comprised 90 patients with familial Parkinson disease,72 sporadic Parkinson disease patients,60 familial essential tremor patients and 90 healthy controls.Exonic regions and exon-intron boundaries of the CHCHD2 gene were amplified by PCR(Polymerase Chain Reaction)and PCR products were purified and directly sequenced to detect variants in CHCHD2 gene.Variants frequencies of Parkinson disease,essential tremor and control groups were analyzed using the Chi-square test.Results:No pathogenic mutation of CHCHD2 gene was found in any of the 90 familial Parkinson disease patients and 60 familial essential tremor patients.Four reported variants(c.-34C>A,c.-9T>G,c.5C>T and c.*125G>A)were found both in Parkinson disease patients and essential tremor patients.The rare variant(c.5C>T)was identified in a familial essential tremor patient and a sporadic Parkinson disease patient,which was reported to be a risk variant for sporadic Parkinson disease in several studies.Conclusion:1.CHCHD2 mutations were relatively rare in Chinese familial Parkinson disease patients.2.CHCHD2 mutations were relatively rare in Chinese familial essential tremor patients.3.The three variants in CHCHD2 gene(c.-34C>A,c.-9T>G and c.*125G>A)may not be risk variants for Parkinson disease and essential tremor.4.Further genetic studies are needed to confirm the relationship between the c.5C>Tin CHCHD2 gene and Chinese patients with Parkinson disease and essential tremor.