LRRK2

Researchers have identified more than 100 LRRK2 gene mutations in families with late-onset Parkinson's disease (the most common form of the disorder, which appears after age 50). These mutations replace single amino acids in the dardarin protein, which affects the protein's structure and function. It is unclear how LRRK2 gene mutations lead to the movement and balance problems characteristic of Parkinson's disease.

A mutation that replaces the amino acid arginine with the amino acid glycine at protein position 1441 (written as Arg1441Gly or R1441G) is a relatively common cause of Parkinson's disease in the Basque region between France and Spain. The protein name dardarin comes from the Basque word "dardara," which means tremor, a characteristic feature of Parkinson's disease.

Studies of several different populations from around the world revealed a common LRRK2 gene mutation in 3 to 7 percent of familial Parkinson's disease cases. This mutation replaces the amino acid glycine with the amino acid serine at protein position 2019 (written as Gly2019Ser or G2019S). The incidence of the Gly2019Ser mutation in familial cases is highest among Arabs from North Africa and people of Ashkenazi (eastern and central European) Jewish ancestry, and it is lowest in Asian and northern European populations. This particular mutation has also been reported in 1 to 3 percent of sporadic Parkinson's disease cases, in which there is no family history of the disease.

Studies in Chinese and Japanese populations have identified an LRRK2 gene mutation that occurs more frequently in people with Parkinson's disease than in people without the disease. This mutation replaces the amino acid glycine with the amino acid arginine at protein position 2385 (written as Gly2385Arg or G2385R). This mutation appears to increase the risk of Parkinson's disease among people in these populations.

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