Associations of common variants in TAAR5, OR6C70, and GBA with hyposmia in Han Chinese individuals with Parkinson’s disease

Hyposmia is one of the cardinal symptoms of Parkinson’s disease (PD), with a considerably high prevalence rate in PD individuals. However, some individuals still retain normal olfactory function. Recent studies have shown that genetic factors may play a role in such a phenomenon. This study aimed to explore the potential genetic factors underlying the variation of olfactory function among PD individuals. Two hundred and three Han Chinese individuals with PD were recruited into this study. All the individuals underwent detailed clinical assessment conducted by experienced neurologists. High-throughput sequencing was performed to identify gene variants associated with PD. TAAR5, OR6C70, and GBA were included in the association analysis. In our study, 85 out of 203 individuals (41.9%) reported normal olfaction, and the other 118 (58.1%) reported hyposmia. Genotype and allele logistic regression models were applied to association analysis. We did not find any significant association of TAAR5 and OR6C70 with hyposmia. However, we found that GBA rs762488 was associated with increased hyposmia risk (P = 0.036, OR = 3.05, 95% CI = 1.08–8.63), while GBA rs1800438 was associated with decreased hyposmia risk (P = 0.032, OR = 0.47, 95% CI = 0.24–0.94). In conclusion, this study revealed the association of GBA with hyposmia, indicating the genetic involvement in PD hyposmia variation. However, we did not replicate previous results (TAAR5 and OR6C70) in this study. Further studies with larger sample sizes in different populations are warranted.