Dopamine β Hydroxylase (DBH) is a potential modifier gene associated with Parkinson's disease in Eastern India

Parkinson's disease (PD) is the debilitating movement disorder, distinguished by dopaminergic and norepinephrinergic neurodegeneration. Apart from candidate gene mutations, several modifier loci have been reported to be associated with the disease manifestation. The Dopamine β-Hydroxylase (DBH) maintains cellular dopamine content and regulates dopamine turn over in neurons. Genetic polymorphisms of DBH are associated with PD and are found to alter plasma DBH activity in patients compared to healthy controls. Therefore, DBH activity in plasma could be a potential and easily detectable biomarkers for alteration of dopaminergic neuronal function in PD.

Plasma DBH activity has been assessed among PD cases and age-matched controls to identify correlation with PD. To elucidate the role of DBH polymorphisms in Eastern Indian PD patients, three SNPs (rs1611115, rs1108580 and rs129882) were selected and screened by PCR-RFLP and DNA sequencing analysis.

The T-allele of rs129882 was more prevalent among patients than controls posing risk (p-value = 0.02, OR = 1.404, 95% CI = 1.047-1.883) towards PD. The dual-Luciferase assay in SHSY5Y cell line revealed that the T-allele of rs129882 increases Luciferase signal (p =  0.0269). However, the rs1611115 and rs1108580 did not show association with PD; plasma DBH activity was not significantly different between patients and controls (p-value > 0.05). Haplotypes constructed with three SNPs showed that the CAT haplotype to pose risk, TAC haplotype to provide protection against early disease onset and CGT being protective against non-motor symptoms.

These data suggest that DBH might influence the susceptibility of PD.