Objective/Rationale:
Autonomic disturbances are common symptoms of Parkinson’s disease (PD). We propose to analyze data on autonomic function collected from PD patients and relatives of PD patients both with mutations in the LRRK2 gene (the greatest known genetic contributor to PD). This will help establish an autonomic profile and identify the quantitative weight of different autonomic symptoms in PD and their prevalence in healthy non-manifesting carriers. To complement the findings, we will assess the integrity of nerves going into the heart in a subset of non-manifesting and manifesting carriers who have some autonomic symptoms.
Project Description:
Four groups from the LRRK2 Cohort Consortium will participate in this study. We will perform analysis of autonomic scores extracted from different standardized questionnaires. Using different statistical methods (models of regression, weight estimation analysis and prediction models), a unified autonomic score will be created. Autonomic profiles will be compared among the different types of LRRK2 mutations to establish whether differences are mutation-specific. In addition, 60 first-degree relatives — both carriers and non-carriers of mutations in the LRRK2 gene — of people with PD will undergo a test to assess nerves in the heart (MIBG cardiac scintigraphy). Correlation between the autonomic profile score, the score on a smell identification test and cardiac nerve integrity will be explored.
Relevance to Diagnosis/Treatment of Parkinson’s Disease:
Autonomic disturbances may appear early in the disease, even prior to the motor symptoms, making them possible biological markers of PD. Asymptomatic family members of patients with PD, especially those who are carriers of mutations known to be associated with the disease, represent a population at risk for PD in its pre-motor state. Establishing an autonomic profile may allow for the identification of individuals in the pre-clinical phase of PD and the provision of early care.
Anticipated Outcome:
The results of this study will help in understanding the relationship between mutations in the LRRK2 gene and autonomic function, and perhaps provide a tool for clinicians to help identify individuals in the pre-clinical phase of the disease.