Subclinical sensory abnormalities in unaffected PINK1 heterozygotes

Mutations in the PINK1 gene, encoding a mitochondrial protein kinase, represent the second cause of autosomal recessive parkinsonism (ARP) after Parkin. While homozygous or compound heterozygous mutations in these genes are unequivocally causative of ARP, the role of single heterozygous mutations is still largely debated. An intriguing hypothesis suggests that these mutations could represent a risk factor to develop parkinsonism, by contributing to nigral cell degeneration. Since the substantia nigra plays an important role in temporal processing of sensory stimuli, as revealed from studies in idiopathic PD, we sought to investigate whether any subclinical sensory abnormalities could be detected in patients with PINK1- related parkinsonism and in unaffected PINK1 heterozygous carriers.