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Recently, a new form of autosomal recessive early-onset parkinsonism (PARK20), due to mutations in the gene encoding the phosphoinositide phosphatase, Synaptojanin 1 (Synj1), has been reported. Several genes responsible for hereditary forms of Parkinson's disease are implicated in distinct steps of the endolysosomal pathway. However, the nature and the degree of endocytic membrane trafficking impairment in early-onset parkinsonism remains elusive. Here, we show that depletion of Synj1 causes drastic alterations of early endosomes, which become enlarged and more numerous, while it does not affect the morphology of late endosomes both in non-neuronal and neuronal cells. Moreover, Synj1 loss impairs the recycling of transferrin, while it does not alter the trafficking of the epidermal growth factor receptor. The ectopic expression of Synj1 restores the functions of early endosomes, and rescues these trafficking defects in depleted cells. Importantly, the same alterations of early endosomal compartments and trafficking defects occur in fibroblasts of PARK20 patients. Our data indicate that Synj1 plays a crucial role in regulating the homeostasis and functions of early endosomal compartments in different cell types, and highlight defective cellular pathways in PARK20. In addition, they strengthen the link between endosomal trafficking and Parkinson's disease.

Presynaptic terminals are metabolically active and accrue damage through continuous vesicle cycling. How synapses locally regulate protein homeostasis is poorly understood. We show that the presynaptic lipid phosphatase synaptojanin is required for macroautophagy, and this role is inhibited by the Parkinson's disease mutation R258Q. Synaptojanin drives synaptic endocytosis by dephosphorylating PI(4,5)P2, but this function appears normal in SynaptojaninRQ knock-in flies. Instead, R258Q affects the synaptojanin SAC1 domain that dephosphorylates PI(3)P and PI(3,5)P2, two lipids found in autophagosomal membranes. Using advanced imaging, we show that SynaptojaninRQ mutants accumulate the PI(3)P/PI(3,5)P2-binding protein Atg18a on nascent synaptic autophagosomes, blocking autophagosome maturation at fly synapses and in neurites of human patient induced pluripotent stem cell-derived neurons. Additionally, we observe neurodegeneration, including dopaminergic neuron loss, in SynaptojaninRQ flies. Thus, synaptojanin is essential for macroautophagy within presynaptic terminals, coupling protein turnover with synaptic vesicle cycling and linking presynaptic-specific autophagy defects to Parkinson's disease.

SYNJ1 has been recently identified by two independent groups as the gene defective in a novel form of autosomal recessive, early-onset atypical parkinsonism (PARK20). Two consanguineous families were initially reported (one of Sicilian and one of Iranian origins), with the same SYNJ1 homozygous mutation (c.773G>A, p.Arg258Gln) segregating with a similar phenotype of early-onset parkinsonism and additional atypical features. Here, we report the identification of the same SYNJ1 homozygous mutation in two affected siblings of a third pedigree. Both siblings had mild developmental psychomotor delay, followed, during the third decade of life, by progressive parkinsonism, dystonia, and mild cognitive impairment. One sibling suffered one episode of generalized seizures. Neuroimaging studies revealed severe nigrostriatal dopaminergic defects, mild striatal and very mild cortical hypometabolism. Treatment with dopamine agonists and anticholinergics resulted in partial improvements. Genetic analyses revealed in both siblings the SYNJ1 homozygous c.773G>A (p.Arg258Gln) mutation. Haplotype analysis suggests that the mutation has arisen independently in this family and the Sicilian PARK20 family previously described by us, in keeping with the hypothesis of a mutational hot spot. This is the third reported family with autosomal recessive, early-onset parkinsonism associated with the SYNJ1 p.Arg258Gln mutation. This work contributes to the definition of the genetic and clinical aspects of PARK20. This newly recognized form must be considered in the diagnostic work-up of patients with early-onset atypical parkinsonism. The presence of seizures might represent a red flag to suspect PARK20.

SYNJ1 has been recently identified by two independent groups as the gene defective in a novel form of autosomal recessive, early-onset atypical parkinsonism (PARK20). Two consanguineous families were initially reported (one of Sicilian and one of Iranian origins), with the same SYNJ1 homozygous mutation (c.773G > A, p.Arg258Gln) segregating with a similar phenotype of early-onset parkinsonism and additional atypical features. Here, we report the identification of the same SYNJ1 homozygous mutation in two affected siblings of a third pedigree. Both siblings had mild developmental psychomotor delay, followed, during the third decade of life, by progressive parkinsonism, dystonia, and mild cognitive impairment. One sibling suffered one episode of generalized seizures. Neuroimaging studies revealed severe nigrostriatal dopaminergic defects, mild striatal and very mild cortical hypometabolism. Treatment with dopamine agonists and anticholinergics resulted in partial improvements. Genetic analyses revealed in both siblings the SYNJ1 homozygous c.773G > A (p.Arg258Gln) mutation. Haplotype analysis suggests that the mutation has arisen independently in this family and the Sicilian PARK20 family previously described by us, in keeping with the hypothesis of a mutational hot spot. This is the third reported family with autosomal recessive, early-onset parkinsonism associated with the SYNJ1 p.Arg258Gln mutation. This work contributes to the definition of the genetic and clinical aspects of PARK20. This newly recognized form must be considered in the diagnostic work-up of patients with early-onset atypical parkinsonism. The presence of seizures might represent a red flag to suspect PARK20.

Assessing the frequency of Wearing-Off (WO) in Parkinson's disease (PD) patients, and its impact on Quality of Life (QoL).

Item does not contain fulltext, Autosomal recessive, early-onset Parkinsonism is clinically and genetically heterogeneous. Here, we report the identification, by homozygosity mapping and exome sequencing, of a SYNJ1 homozygous mutation (p.Arg258Gln) segregating with disease in an Italian consanguineous family with Parkinsonism, dystonia, and cognitive deterioration. Response to levodopa was poor, and limited by side effects. Neuroimaging revealed brain atrophy, nigrostriatal dopaminergic defects, and cerebral hypometabolism. SYNJ1 encodes synaptojanin 1, a phosphoinositide phosphatase protein with essential roles in the postendocytic recycling of synaptic vesicles. The mutation is absent in variation databases and in ethnically matched controls, is damaging according to all prediction programs, and replaces an amino acid that is extremely conserved in the synaptojanin 1 homologues and in SAC1-like domains of other proteins. Sequencing the SYNJ1 ORF in unrelated patients revealed another heterozygous mutation (p.Ser1422Arg), predicted as damaging, in a patient who also carries a heterozygous PINK1 truncating mutation. The SYNJ1 gene is a compelling candidate for Parkinsonism; mutations in the functionally linked protein auxilin cause a similar early-onset phenotype, and other findings implicate endosomal dysfunctions in the pathogenesis. Our data delineate a novel form of human Mendelian Parkinsonism, and provide further evidence for abnormal synaptic vesicle recycling as a central theme in the pathogenesis.

Item does not contain fulltext, Autosomal recessive, early-onset Parkinsonism is clinically and genetically heterogeneous. Here, we report the identification, by homozygosity mapping and exome sequencing, of a SYNJ1 homozygous mutation (p.Arg258Gln) segregating with disease in an Italian consanguineous family with Parkinsonism, dystonia, and cognitive deterioration. Response to levodopa was poor, and limited by side effects. Neuroimaging revealed brain atrophy, nigrostriatal dopaminergic defects, and cerebral hypometabolism. SYNJ1 encodes synaptojanin 1, a phosphoinositide phosphatase protein with essential roles in the postendocytic recycling of synaptic vesicles. The mutation is absent in variation databases and in ethnically matched controls, is damaging according to all prediction programs, and replaces an amino acid that is extremely conserved in the synaptojanin 1 homologues and in SAC1-like domains of other proteins. Sequencing the SYNJ1 ORF in unrelated patients revealed another heterozygous mutation (p.Ser1422Arg), predicted as damaging, in a patient who also carries a heterozygous PINK1 truncating mutation. The SYNJ1 gene is a compelling candidate for Parkinsonism; mutations in the functionally linked protein auxilin cause a similar early-onset phenotype, and other findings implicate endosomal dysfunctions in the pathogenesis. Our data delineate a novel form of human Mendelian Parkinsonism, and provide further evidence for abnormal synaptic vesicle recycling as a central theme in the pathogenesis.

The Movement Disorder Society-sponsored revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS) has been available in English since 2008. As part of this process, the MDS-UPDRS organizing team developed guidelines for development of official non-English translations. We present here the formal process for completing officially approved non-English versions of the MDS-UPDRS and specifically focus on the first of these versions in Italian. The MDS-UPDRS was translated into Italian and tested in 377 native-Italian speaking PD patients. Confirmatory and exploratory factor analyses determined whether the factor structure for the English-language MDS-UPDRS could be confirmed in data collected using the Italian translation. To be designated an 'Official MDS translation,' the Comparative Fit Index (CFI) had to be ≥0.90 relative to the English-language version. For all four parts of the Italian MDS-UPDRS, the CFI, in comparison with the English-language data, was ≥0.94. Exploratory factor analyses revealed some differences between the two datasets, however these differences were considered to be within an acceptable range. The Italian version of the MDS-UPDRS reaches the criterion to be designated as an Official Translation and is now available for use. This protocol will serve as outline for further validation of this in multiple languages. © 2012 Springer-Verlag.