Causes Parkinson's disease is caused by a loss of nerve cells in part of the substantia nigra, which leads to a reduction in the amount of a chemical called dopamine in the brain Dopamine plays a vital role in regulating the movement of the body and reduced dopamine level is responsible for many of the symptoms The cause behind loss of nerve cells is unclear most experts think it is due to a combination of genetic and environmental factors Diminished substantia nigra as seen in Parkinsons diseaseCauses • Parkinson’s disease is caused by a loss of nerve cells in part of the substantia nigra, which leads to a reduction in the amount of a chemical called dopamine in the brain. • Dopamine plays a vital role in regulating the movement of the body and reduced dopamine level is responsible for many of the symptoms. • The cause behind loss of nerve cells is unclear. Most experts think it is due to a combination of genetic and environmental factors