In 2015 the Movement Disorder Society (MDS) Task Force recommended research criteria for the estimation of prodromal PD. We aimed to evaluate, for the first time, the criteria in first-degree relatives of Ashkenazi Jewish G2019S- LRRK2 PD patients, who are considered a population at risk for developing PD, and assess the sensitivity and specificity of the criteria in identifying phenoconverters.
Participants were evaluated longitudinally over a period of 5 years (average follow-up 49.2±12.3 months). Likelihood ratios (LR) and probability estimations were calculated based on the MDS Research Criteria for Prodromal Parkinson’s Disease markers and examined for each assessment point.
120 healthy carriers (HC) (49.53±13.4 yrs; 54%F) and 111 healthy non-carriers (HNC) (48.43±15.79 yrs; 49%F) participated in this study. Probability scores were significantly higher in HC than HNC (p<0.0001). Of the twenty participants (8.6%) who met criteria for probable prodromal PD at baseline, 17 were HC. Participants who reached the threshold were older (p<0.0001), had higher UPDRS-III (p<0.001), lower cognitive function (p=0.001) and more non-motor symptoms (p<0.0001), compared to those who did not. Ten participants were diagnosed with incident-PD within 5 years from baseline resulting in a specificity of 91.82%(95%CI:86.69–96.94), sensitivity of 80%(95%CI:55.21–100%), PPV of 47.06% (95%CI:23.33–70.79) and NPV of 98.06% (95%CI:95.39–100). All 10 phenoconvertors were G2019S- LRRK2 carriers.