Researchers are still attempting to find the cause of Parkinson's disease in any age group. But, one of the biggest questions both patients and caregivers typically have is, why are some patients diagnosed with Parkinson's disease younger than others? Studies have already found that Parkinson's disease is caused by a mix of environmental and genetic factors. However, according to the National Parkinson Foundation, 65% of patients with early onset Parkinson's disease, specifically before the age of 20, develop the disease from a genetic mutation. They also state that this mutation affects 32% of patients who are diagnosed with the disease between the ages of 20 and 30. Environmental factors of Parkinson's disease includes insecticides and herbicides.