Rare Variants May Influence Disease Risk and Clinical Features in Sporadic Late-Onset Chinese Parkinson's Disease Patients.

Heritability in Parkinson's disease (PD) may be driven by rare variants (RVs), but genetic data for Chinese cohorts remain limited. We investigated the relationship between RVs and the risk and phenotype of PD by performing targeted exome sequencing of 29 PD candidate genes in 311 late-onset, sporadic Chinese PD patients and 699 local controls. A total of 174 RVs (that were likely deleterious using in silico prediction tools) were identified in 27 of the 29 genes sequenced. Mean RV burden was higher (1.178 vs. 0.478, p = 1.26 × 10-24) and HLA-DRB5 p.Val104ArgfsTer26 was enriched in PD patients (0.207 vs. 0.000, p < 0.0003) compared with controls. Gene-based RV carrier status in PD patients was then examined for correlation with phenotypic characteristics. The RV carrier status of LRRK2 and HLA-DRB5 was associated with tremor, SREBF1 with gait disturbance, and SYNJ1 and SCARB2 with motor fluctuations. Earlier onset age and neuropsychiatric symptoms were associated with GBA1 variants. Olfactory deficit, autonomic disturbance, anxiety and depression were associated with variants in SLC44A1, HLA-DRB5, and SCARB2 respectively. Our results demonstrated a prominent RV burden in Chinese PD and illustrated the importance of genetic influence on the risk and phenotype of sporadic PD. Further studies are warranted to correlate these genes with putative pathogenic pathways.