LRRK2 and Parkinson disease: Similarly, various genetic (e.g., LRRK2 and TNF-α variants) (26, 27), environmental (e.g., pesticides), or lifestyle factors (diet, exercise, or antibiotic use) (28, 29) increase the risk or progression of Parkinson’s disease and are also associated with gut malformations and inflammatory bowel disease, which itself is considered a risk factor for Parkinson’s disease (30, 31).