SNCA and mTOR Pathway Single Nucleotide Polymorphisms Interact to Modulate the Age at Onset of Parkinson's Disease.

BACKGROUND: Single nucleotide polymorphisms (SNPs) in the α-synuclein (SNCA) gene are associated with differential risk and age at onset (AAO) of both idiopathic and Leucine-rich repeat kinase 2 (LRRK2)-associated Parkinson's disease (PD). Yet potential combinatory or synergistic effects among several modulatory SNPs for PD risk or AAO remain largely underexplored. OBJECTIVES: The mechanistic target of rapamycin (mTOR) signaling pathway is functionally impaired in PD. Here we explored whether SNPs in the mTOR pathway, alone or by epistatic interaction with known susceptibility factors, can modulate PD risk and AAO. METHODS: Based on functional relevance, we selected a total of 64 SNPs mapping to a total of 57 genes from the mTOR pathway and genotyped a discovery series cohort encompassing 898 PD patients and 921 controls. As a replication series, we screened 4170 PD and 3014 controls available from the International Parkinson's Disease Genomics Consortium. RESULTS: In the discovery series cohort, we found a 4-loci interaction involving STK11 rs8111699, FCHSD1 rs456998, GSK3B rs1732170, and SNCA rs356219, which was associated with an increased risk of PD (odds ratio = 2.59, P < .001). In addition, we also found a 3-loci epistatic combination of RPTOR rs11868112 and RPS6KA2 rs6456121 with SNCA rs356219, which was associated (odds ratio = 2.89; P < .0001) with differential AAO. The latter was further validated (odds ratio = 1.56; P = 0.046-0.047) in the International Parkinson's Disease Genomics Consortium cohort. CONCLUSIONS: These findings indicate that genetic variability in the mTOR pathway contributes to SNCA effects in a nonlinear epistatic manner to modulate differential AAO in PD, unraveling the contribution of this cascade in the pathogenesis of the disease. © 2019 International Parkinson and Movement Disorder Society.

MTOR Pathway-Based Discovery of Genetic Susceptibility to L-DOPA-Induced Dyskinesia in Parkinson's Disease Patients.

Dyskinesia induced by L-DOPA administration (LID) is one of the most invalidating adverse effects of the gold standard treatment restoring dopamine transmission in Parkinson's disease (PD). However, LID manifestation in parkinsonian patients is variable and heterogeneous. Here, we performed a candidate genetic pathway analysis of the mTOR signaling cascade to elucidate a potential genetic contribution to LID susceptibility, since mTOR inhibition ameliorates LID in PD animal models. We screened 64 single nucleotide polymorphisms (SNPs) mapping to 57 genes of the mTOR pathway in a retrospective cohort of 401 PD cases treated with L-DOPA (70 PD with moderate/severe LID and 331 with no/mild LID). We performed classic allelic, genotypic, and epistatic analyses to evaluate the association of individual or combinations of SNPs with LID onset and with LID severity after initiation of L-DOPA treatment. As for the time to LID onset, we found significant associations with SNP rs1043098 in the EIF4EBP2 gene and also with an epistatic interaction involving EIF4EBP2 rs1043098, RICTOR rs2043112, and PRKCA rs4790904. For LID severity, we found significant association with HRAS rs12628 and PRKN rs1801582 and also with a four-loci epistatic combination involving RPS6KB1 rs1292034, HRAS rs12628, RPS6KA2 rs6456121, and FCHSD1 rs456998. These findings indicate that the mTOR pathway contributes genetically to LID susceptibility. Our study could help to identify the most susceptible PD patients to L-DOPA in order to prevent the appearance of early and/or severe LID in a future. This information could also be used to stratify PD patients in clinical trials in a more accurate way.

Regional Overlap of Pathologies in Lewy Body Disorders.

Lewy body disorders (LBD) are common neurodegenerative diseases characterized by the presence of aggregated α-synuclein in Lewy bodies and Lewy neurites in the central and peripheral nervous systems. The brains of patients with LBD often display other comorbid pathologies, i.e. insoluble tau, ß-amyloid aggregates, TAR DNA-binding protein 43 (TDP-43) deposits, and argyrophilic grain disease (AGD). The incidence and physiological relevance of these concurrent pathological findings remain controversial. We performed a semiquantitative detailed mapping of α-synuclein, tau, ß-amyloid (Aß), TDP-43, and AGD pathologies in 17 areas in 63 LBD cases (44 with Parkinson disease [PD], 28 with dementia, and 19 with dementia with Lewy bodies). APOE and MAPT genetic variants were also investigated. A majority of LBD cases had 2 or 3 concomitant findings, particularly Alzheimer disease-related pathology. Pathological stages of tau, ß-amyloid and α-synuclein pathologies were increased in cases with dementia. Aß score was the best correlate of the time to dementia in PD. In addition, ß-amyloid deposition correlated with α-synuclein load in all groups. MAPT H1 haplotype did not influence any assessed pathology in PD. These results highlight the common concurrence of pathologies in patients with LBD that may have an impact on the clinical expression of the diseases.

Consenso de la Asociación Colombiana de Neurología sobre el uso de apomorfina en la enfermedad de Parkinson / Colombian Association of Neurology Consensus on the use of Apomorphine in Parkinson's disease

La apomorfina es un agonista dopa que se viene usando desde hace más 25 años en el tratamiento de la enfermedad de Parkinson avanzada con complicaciones motoras complejas, por lo cual sigue siendo de gran importancia en el tratamiento de esta etapa de la enfermedad. En el siguiente escrito, realizado por el Comité de Movimientos Anormales de la Asociación Colombiana de Neurología, se hace una revisión respecto a la medicación, su eficacia y el papel en el manejo de la enfermedad de Parkinson, así como una comparación entre las diferentes terapias avanzadas disponibles hoy en día. De la misma manera el Comité hace recomendaciones sobre las indicaciones, elección de candidatos y protocolos para el inicio de las diferentes formas de administración (intermitente e infusión continua) para optimizar el uso de esta terapia y facilitar la adherencia al tratamiento. Por otra parte, se revisan los efectos adversos relacionados con la terapia y se hacen recomendaciones sobre el manejo de las mismas, el seguimiento que se debe hacer a los pacientes que reciban apomorfina y las claves en el tratamiento a largo plazo. long term.

Apomorphine is a dopamine agonist that has been used for more than 25 years in the treatment of advanced Parkinson's disease with complex motor complications, becoming an important treatment option for this stage of the disease. In the following document, written by the movement disorders committee of the Colombian Association of Neurology, an extensive review is made about this medication, its efficacy and role in the management of Parkinson's disease as well as a comparison between the different advanced therapies available today. Additionally, recommendations about the indications, election of candidates and protocols for choosing between the different forms of administration (intermittent and continuous infusion) are establish according current evidence in order to help clinicians to optimize the use of this therapy and facilitate adherence to treatment. On the other hand, adverse effects related to the therapy are reviewed and recommendations are made about their management, as well as a protocol to follow-up patients receiving apomorphine and keys in the long term.