PINK1 and Parkin, the products of two genes responsible for autosomal recessive Parkinsonian syndromes with early onset, act as a quality control system on the outer mitochondrial membrane to preserve mitochondrial integrity.
Two new AREP loci (PARK6 and PARK7) have been recently mapped on chromosome 1p and confirmed in independent datasets, suggesting that both might be frequent.
The aim of this study was to elucidate whether sensory abnormalities are present and may precede motor symptoms in familial parkinsonism by characterizing sensory function in symptomatic and asymptomatic PINK1 mutation carriers.
All sites of mutations were novel, suggesting that PINK1 may be the second most common causative gene next to parkin in parkinsonism with the recessive mode of inheritance.
Mutations in PINK1 (PTEN-induced putative kinase 1) are causal for early onset recessive parkinsonism in humans, characterized by damage to the nigrostriatal system.
The identification of a higher number of patients (5%) than controls (1%) carrying a single heterozygous mutation, along with previous positron emission tomography studies demonstrating a preclinical nigrostriatal dysfunction in PARK6 carriers, supports the hypothesis that haploinsufficiency of PINK1, as well as of other EOP genes, may represent a susceptibility factor toward parkinsonism.
The recessive Parkinsonism-linked genes PTEN-induced kinase 1 (PINK1) and Parkin maintain mitochondrial integrity by regulating diverse aspects of mitochondrial function, including membrane potential, calcium homeostasis, cristae structure, respiratory activity, and mtDNA integrity.
Other entities entailing dystonia-parkinsonism include dopamine transporter deficiency syndrome (SLC63 mutations); dopa-responsive dystonias; young-onset parkinsonism (PARKIN, PINK1 and DJ-1 mutations); PRKRA mutations; and X-linked TAF1 mutations, which rarely can also manifest in women.
Here, we describe a novel homozygous mutation (Q126P), identified in two affected German sisters with a clinical phenotype typical for PINK1-associated parkinsonism.
Loss-of-function mutations in the PTEN-induced kinase 1 (PINK1) or parkin genes, which encode a mitochondrially localized serine/threonine kinase and a ubiquitin-protein ligase, respectively, result in recessive familial forms of Parkinsonism.