Parkinson’s disease, a neurodegenerative disorder, has prominent symptoms like tremor, rigidity, akinesia and bradykinesia. Cases of Parkinson’s disease are reported to be more in old age, mostly above the age of 60 years. Loss of dopaminergic neurons of the substantia nigra causes lack of motor functions. The dopaminergic neurons synthesizing dopamine from L-tyrosine degenerate. Both genetic and environmental factors are supposed to cause and enhance the disease. A number of genes (PARK1, Parkin, UCHL1, LRRK2, DJ1, PINK1) linked to Parkinson’s disease had been identified. The entire mechanism of the gene action has not yet been revealed. Symptoms of Parkinson’s disease are reported to be reduced by treatment at early stages of the disease onset. Complete cure for Parkinson’s disease has not yet been worked out. Genetically engineered stem cells that form dopaminergic neurons are supposed to be an effective treatment for Parkinson’s disease.

Key words: Dopamine, neurodegenerative, levadopa, dopaminergic pathway, substantia nigra.