Parkinson’s disease is a progressive neurodegenerative disorder marked by tremor, muscle rigidity, slowness of movement and postural instability. It is primarily caused by the loss of dopamine producing neurons in the substantia nigra, a region of the midbrain that normally helps coordinate smooth and purposeful movement. As dopamine levels fall, the communication between brain regions that control motion is disrupted, leading to the characteristic motor symptoms. Many people also develop non motor features such as sleep disturbances, depression, constipation and cognitive decline.

Research points to a combination of genetic and environmental influences. Certain gene mutations increase risk, while exposures such as pesticides, solvents and heavy metals are suspected contributors. A key biological hallmark is the accumulation of misfolded alpha synuclein protein in clumps known as Lewy bodies, which may damage neurons and spread through connected brain regions.

Standard treatment uses medications that boost or mimic dopamine, such as levodopa and dopamine agonists, to reduce motor symptoms. Over time, however, these therapies often become less effective and can produce complications like involuntary movements. Surgical approaches such as deep brain stimulation electrically modulate specific brain circuits and can significantly improve quality of life in selected patients.

Active research areas include drugs that target alpha synuclein aggregation, therapies that protect or restore dopamine neurons, gene therapies aimed at correcting molecular defects and cell replacement strategies using stem cell derived neurons. Studies are also exploring biomarkers for earlier diagnosis, when interventions might slow or prevent progression.