PARK6 is a common cause of familial parkinsonism.

The Parkin gene is responsible for about 50% of autosomal recessive juvenile parkinsonism (ARJP) and less than 20% of sporadic early onset cases. We recently mapped a novel ARJP locus (PARK6) on chromosome 1p. Linkage to PARK6 was confirmed in 8 families from 4 different European countries. These families share some clinical features with the European Parkin-positive cases, with a wide range of ages at onset and slow progression. However, features typical of ARJP, such as dystonia and sleep benefit, were not observed, making the clinical presentation of late-onset cases indistinguishable from that of idiopathic PD. The determination of the smallest region of homozygosity in one consanguineous family allowed reducing the candidate interval to 9 cM. PARK6 appears to be an important locus for ARJP in Europe.