Objective: To assess the cognitive phenotype of glucocerebrosidase (GBA) mutation carriers with early-onset Parkinson disease (PD). Methods:We administered a neuropsychological battery and the University of Pennsylvania Smell Identification Test (UPSIT) to participants in the CORE-PD study who were tested for mutations in PARKIN, LRRK2, and GBA. Participants included 33 GBA mutation carriers and 60 noncarriers of any genetic mutation. Primary analyses were performed on 26 GBA heterozygous mutation carriers without additional mutations and 39 age-and PD duration-matched noncarriers. Five cognitive domains, psychomotor speed, attention, memory, visuospatial function, and executive function, were created from transformed z scores of individual neuropsychological tests. Clinical diagnoses (normal, mild cognitive impairment [MCI], dementia) were assigned blind to genotype based on neuropsychological performance and functional impairment as assessed by the Clinical Dementia Rating (CDR) score. The association between GBA mutation status and neuropsychological performance, CDR, and clinical diagnoses was assessed.

This study suggests that the Glucocerebrosidase gene may be a susceptibility gene for Parkinson disease and that Glucocerebrosidase mutations may modify age at onset.

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Objective: Estimates of the penetrance of LRRK2 G2019S vary widely (24%-100%), reflective of differences in ascertainment, age, sex, ethnic group, and genetic and environmental modifiers. Methods:The kin-cohort method was used to predict penetrance in 2,270 relatives of 474 Ashkenazi Jewish (AJ) Parkinson disease (PD) probands in the Michael J. Fox LRRK2 AJ Consortium in New York and Tel Aviv, Israel. Patients with PD were genotyped for the LRRK2 G2019S mutation and at least 7 founder GBA mutations. GBA mutation carriers were excluded. A validated family history interview, including age at onset of PD and current age or age at death for each first-degree relative, was administered. Neurologic examination and LRRK2 genotype of relatives were included when available.Results: Risk of PD in relatives predicted to carry an LRRK2 G2019S mutation was 0.26 (95% confidence interval [CI] 0.18-0.36) to age 80 years, and was almost 3-fold higher than in relatives predicted to be noncarriers (hazard ratio [HR] 2.89, 95% CI 1.73-4.55, p , 0.001). The risk among predicted G2019S carrier male relatives (0.22, 95% CI 0.10-0.37) was similar to predicted carrier female relatives (0.29, 95% CI 0.18-0.40; HR male to female: 0.74, 95% CI 0.27-1.63, p 5 0.44). In contrast, predicted noncarrier male relatives had a higher risk (0.15, 95% CI 0.11-0.20) than predicted noncarrier female relatives (0.07, 95% CI 0.04-0.10; HR male to female: 2.40, 95% CI 1.50-4.15, p , 0.001). Conclusion:Penetrance of LRRK2 G2019S in AJ is only 26% and lower than reported in other ethnic groups. Further study of the genetic and environmental risk factors that influence G2019S penetrance is warranted. Neurology ® 2015;85:89-95 GLOSSARY AJ 5 Ashkenazi Jewish; CI 5 confidence interval; FHI 5 family history interview; GBA 5 glucocerebrosidase; HR 5 hazard ratio; PD 5 Parkinson disease.

Objective Recent studies demonstrated an association between a Mediterranean-type diet and Alzheimer’s risk. We assessed the association between Mediterranean-type diet adherence and PD status. Methods 257 PD participants and 198 controls completed the Willett semi-quantitative questionnaire that quantifies diet during the past year. Scores were calculated using a 9-point scale; higher scores indicated greater adherence to the Mediterranean-type diet. Logistic regression models were used to assess the association between PD status and Mediterranean-type diet, adjusting for caloric intake, age, gender, education and ethnicity. Adjusted linear regression models were used to examine the association between Mediterranean-type diet adherence and PD age-at-onset. Results Higher Mediterranean-type diet adherence was associated with reduced odds for PD after adjustment for all covariates (OR=0.86, 95%CI=0.77–0.97, p=0.010). Lower Mediterranean-type diet score was associated with earlier PD age-at-onset (β=1.09, p=0.010). Conclusions PD patients adhere less than controls to the Mediterranean-type diet. Dietary behavior may be associated with age-at-onset.