Two new international studies by researchers at the Mayo Clinic site in Florida are rounding out the notion that Parkinson’s disease is largely caused by inherited genetic mutations that pass through scores of related generations over hundreds, if not thousands of years. These genetic influences, which can be small but additive, or large and causative, overturn common beliefs that the neurodegenerative disease mostly occurs in a random fashion or is due to undetermined environmental factors.

These latest studies bring the total of number of disease-related mutations in an as yet poorly understood gene, leucine-rich repeat kinase 2 (LRRK2), to seven, all of which are linked, either weakly or strongly, to typical, late onset development of Parkinson’s disease in people around the world. One mutation (R1628P) doubles the risk of Parkinson’s disease in ethnic Chinese, according to a study published on Wednesday, April 16, 2008 in the online edition of the Annals of Neurology. The second study, published April 15 in Neurology, demonstrates that another very rare mutation (R1441C), found in people on three continents, increases risk by more than 10-fold. … Continue Reading »