Family History in Parkinson's Disease: A National Cross‐Sectional Study

Background: Family history of Parkinson's disease (PD) is a common finding in PD patients. However, a few studies have systematically examined this aspect. Objectives: We investigated the family history of PD patients, comparing demographic and clinical features between familial PD (fPD) and sporadic PD (sPD). Methods: A cross-sectional study enrolling 2035 PD patients was conducted in 28 Italian centers. Clinical data and family history up to the third degree of kinship were collected. Results: Family history of PD was determined in 21.9% of patients. fPD patients had earlier age at onset than sporadic patients. No relevant differences in the prevalence of motor and nonmotor symptoms were detected. Family history of mood disorders resulted more prevalently in the fPD group. Conclusions: fPD was found to recur more frequently than previously reported. Family history collection beyond the core family is essential to discover disease clusters and identify novel risk factors for PD.