PARK7 and Parkinson disease: Protein DJ-1, produced by the PARK7 gene, hasbeen implicated in familial Parkinson’s disease, where homozygousor compound heterozygous mutations have been shown to lead to earlyonset of disease.1−4 DJ-1 is a 189-amino acid protein that is ubiquitously expressedand is primarily cytosolic,5 although itis reported to be present in other cellular compartments includingthe mitochondria and nucleus.6,7 In addition to its causativerole in Parkinson’s disease, DJ-1 appears to have relevancein a variety of diseases and other physiological contexts.