Genetics

There are several genes that are known to cause PD, but they account for a very small minority of cases. The most important is a gene called parkin. The parkin gene creates a protein, also called parkin, that helps to break down defective proteins inside brain cells (neurons). When the parkin gene is altered, or mutated, this function is impaired. It is hypothesized that the accumulation of defective proteins contributes to death of neurons. Two mutated copies of parkin are needed to develop PD. This type of inheritance pattern is called "autosomal recessive." One copy of the defective gene is inherited from each parent. Parkin mutations cause young-onset PD, with symptoms beginning usually in the 40s. Parkin mutations are the most common genetic cause of PD, but still account for less than one percent of all cases.

Other known genes for PD include alpha-synuclein, DJ-1, PINK-1, and UCHL-1, but altogether these represent only a small number of PD cases.

	Diagnosis