Discovery of the parkin gene; the gene for young onset autosomal recessive parkinsonism (AR)]

We discovered the gene for young onset autosomal recessive parkinsonism in 1998. We were gifted two lucky episodes. This is a short history on how we were able to discover the gene in a short period. We were primarily interested in the pathogenesis of sporadic Parkinson's disease (PD). We decided to do a genetic association study using a polymorphism of manganese superoxide dismutase (Mn SOD), as it is located at the pivotal position of oxidative stress and mitochondria. While we were screening many patients, we encountered what appeared to be young onset autosomal recessive family, which appeared to be linked to the sod2 locus, which had been mapped to the long arm of chromosome 6. We did linkage analysis on 13 similar families and obtained lod score above 9. Another fortune was that while doing linkage analysis, we encountered a patient who showed complete absence of one of the microsatellite markers that we were using in the linkage analysis. We thought that the marker was likely to be located within the disease gene. We started molecular cloning using this marker as the initial probe. Eventually we were able to clone a novel gene, which we named as parkin.