Analysis of mutations and the association between polymorphisms in the cerebral dopamine neurotrophic factor (CDNF) gene and Parkinson disease

Neurotrophic factors support the survival of dopaminergic neurons. The cerebral dopamine neurotrophic factor (CDNF) is a novel neurotrophic factor with strong trophic activity on dopaminergic neurons comparable to that of glial cell line-derived neurotrophic factor (GDNF). To investigate whether rare or common variants in CDNF are associated with Parkinson disease (PD), we performed mutation analysis of CDNF and a genetic association study between CDNF polymorphisms and PD. We screened 110 early-onset Parkinson disease (EOPD) patients for CDNF mutations. Allelic and genotype frequencies of 3 CDNF single nucleotide polymorphisms (SNPs) (rs1901650, rs7094179, and rs11259365) were compared in 215 PD patients and age- and sex-matched controls. We failed to identify any mutations in CDNF among the EOPD patient sample population. We observed a trend towards increased risk for PD in patients carrying the C allele of SNP rs7094179 (odds ratio (OR)=1.27, 95% confidence interval (CI) 0.96-1.67). Patients carrying the C allele were susceptible to PD in both dominant (CC+CA vs. AA; OR=7.20, 95% CI 0.88-59.1) and recessive (CA+AA vs. CC; OR=0.64, 95% CI 0.41-0.99) models. Genotype and allele frequencies of SNPs rs1901650 and rs11259365 did not differ between PD patients and controls. Our study suggests that the C allele of an intronic CDNF SNP (rs7094179) might be an allele for susceptibility to PD. Further studies with larger sample size are required to confirm our results.