SAA positivity rate amongst dual LRRK2-GBA1, GBA1 and LRRK2 carriers with Parkinson’s disease

We investigated whether people with Parkinson’s disease who are dual GBA1+LRRK2 carriers have a milder, LRRK2-like phenotype as previously reported. This was accomplished by comparing clinical features and alpha-synuclein seed amplification assay (SAA) positivity rates between dual GBA1+LRRK2-PD(n=13), GBA1-PD(n=169) and LRRK2-PD(n=175) carriers in a cross-sectional retrospective study of Parkinson’s Progression Markers Initiative (PPMI) data. Our results show that GBA1+LRRK2-PD SAA positivity rate(83%) is closer to GBA1-PD rate(87%) rather than LRRK2-PD rate(62%,p-value>0.05). GBA1+LRRK2-PD have both non-motor and motor phenotypic similarity to GBA1-PD,(p-value>0.05). This small PPMI cohort indicates that dual GBA1+LRRK2-PD carriers’ SAA positivity and phenotype are aligned with GBA1-PD.