Past, present, and future of Parkinson's disease: A special essay on the 200th Anniversary of the Shaking Palsy.

This article reviews and summarizes 200 years of Parkinson's disease. It comprises a relevant history of Dr. James Parkinson's himself and what he described accurately and what he missed from today's perspective. Parkinson's disease today is understood as a multietiological condition with uncertain etiopathogenesis. Many advances have occurred regarding pathophysiology and symptomatic treatments, but critically important issues are still pending resolution. Among the latter, the need to modify disease progression is undoubtedly a priority. In sum, this multiple-author article, prepared to commemorate the bicentenary of the shaking palsy, provides a historical state-of-the-art account of what has been achieved, the current situation, and how to progress toward resolving Parkinson's disease. © 2017 International Parkinson and Movement Disorder Society.

Clinical, imaging, and molecular findings in a sample of Mexican families with pantothenate kinase-associated neurodegeneration.

Pantothenate kinase-associated neurodegeneration (PKAN) is an autosomal recessive disorder characterized by iron accumulation in the brain, because of mutations in the PANK2 gene. Phenotypic and genotypic characteristics of 11 patients from five Mexican families with PKAN disease are reported. Sequencing of PANK2 confirmed the diagnosis. The 11 patients had dysarthria associated with dystonia and Parkinsonism in six. Brain magnetic resonance imaging (MRI) showed the 'eye-of-the-tiger' sign in all patients. Three different mutations were identified, a novel one (p.A469P) and two (p.G219V and p.N404I) very rare. Homozygous sibs for the p.G219V mutation had a severe disease progression with early death. Dystonia predominated in the p.A469P/p.N404I compound heterozygous patients. Homozygous for p.N404I showed Parkinsonism, tics and personality and speech disorders. Early and late disease onset and variable expression was present in carriers of the different identified mutations. The 'eye-of-the-tiger' is an excellent neuroimaging hallmark to predict PANK2 mutations. We detected a 'cluster' of patients harboring the p.N404I mutation, strongly suggesting a founder effect for this mutation. This is the first familial clinical-genetic PKAN disease study accomplished in Mexico.

Assessing the non-motor symptoms of Parkinson's disease: MDS-UPDRS and NMS Scale.

BACKGROUND AND PURPOSE: Although Parkinson's disease (PD) is characterized by typical motor manifestations, non-motor symptoms (NMS) are an outstanding part of the disease. At present, several specific instruments for assessment of NMS are available. The objective of our study was to determine the performance of the Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS): Part I - Non-Motor Aspects of Experiences of Daily Living (nM-EDL) compared with the Non-Motor Symptoms Scale (NMSS). METHODS: To this purpose, 434 consecutive patients with PD were included in an international, observational, cross-sectional study. The association between scores of both scales was determined by the Spearman rank correlation coefficient. Equations for transformation of total score of a scale to the other were constructed from weighted regression models and both, transformed and observed score, contrasted by means of the Lin's Concordance Correlation Coefficient (LCCC) and Bland-Altman plot. RESULTS: As a whole, the prevalence of the NMS according to each scale was quite similar, and most of the correlations between their corresponding components were high (r(S) > 0.60). The total score correlation of the MDS-UPDRS Part I with the NMSS was high (r(S) = 0.81). Concerning the transformed scores, estimated scores only partially approach the observed ones (sharing about 60-64% of the variance) because residual variance increased with increasing magnitudes of the scores, i.e. the most severe patients (Bland-Altman plot; LCCC < 0.60 for severe patients). CONCLUSIONS: (i) MDS-UPDRS Part I (nM-EDL) and NMSS showed a strong convergent validity; (ii) however, transformed scores using the equations from weighted regression models showed that for patients with the most severe NMS they are not concordant.

Factors associated with the quality of life of subjects with Parkinson's disease and burden on their caregivers.

INTRODUCTION: Parkinson's disease affects the quality of life of the individual with the disease in addition to creating a burden on the caregiver. Factors related to these effects include motor and non-motor aspects of the disease, as well as traits inherent to the caregiver. METHODS: We evaluated subjects with Parkinson's disease using the following instruments: Quality of Life Questionnaire PDQ-8, Movement Disorders Society Unified Parkinson's disease Rating Scale part i to iv (MDS-UPDRS), and Hoehn and Yahr staging. The Zarit Burden Inventory was used to assess all primary caregivers. Major demographic and clinical variables were also recorded. RESULTS: A total of 250 subjects with Parkinson's disease were included, of whom 201 had a primary caregiver. In the multivariate analysis, predictors of poor quality of life for a subject with Parkinson's disease were the MDS-UPDRS I score (ß=.39, P<.001), MDS-UPDRS II score (ß=.21, P<.001), and MDS-UPDRS III score (ß=.07, P=.004). Regarding caregiver burden, the MDS-UPDRS II score (ß=.54, P=.007) was the most influential factor. CONCLUSIONS: The present study shows a relationship between quality of life for the subject with Parkinson's disease and the caregiver's perceived burden. However, the factors that determine each situation appear to be distinct.

Clinical assessment and health-related quality of life in patients with non-cardiac chest pain.

INTRODUCTION: Non-cardiac chest pain (NCCP) is mainly related to oesophageal disease, and in spite of being a common condition in Mexico, information regarding it is scarce. AIM: To assess the clinical characteristics and health-related quality of life of patients with NCCP of presumed oesophageal origin. MATERIAL AND METHODS: Patients with NCCP of presumed oesophageal origin with no previous treatment were included in the study. Associated symptoms were assessed and upper gastrointestinal endoscopy and 24-hour oesophageal pH monitoring were performed to diagnose gastroesophageal reflux disease, while oesophageal manometry was used to determine oesophageal motility disorders. The SF-36 Health-Related Quality of Life (HR-QoL) questionnaire was completed and its results compared to a control group without oesophageal symptoms. RESULTS: The study included 33 patients, of which 61% were women, and the mean age was 46.1 (±11.6) years. Causes of NCCP were gastroesophageal reflux disease in 48%, achalasia in 34%, and functional chest pain in 18%. The average progression time for chest pain was 24 (2-240) months, with ≤ 3 events/week in 52% of the patients. The most frequent accompanying symptoms were: regurgitation (81%), dysphagia (72%) and heartburn (66%). Patients with NCCP show deterioration in HR-QoL compared to the control group (P=.01), regardless of chest pain aetiology. The most affected areas were general perception of health, emotional issues, and mental health sub-scale (P>0.05). CONCLUSIONS: In our population, patients with NCCP show deterioration in HR-QoL regardless of the aetiology, frequency, and accompanying symptoms.

Relationship between the MDS-UPDRS domains and the health-related quality of life of Parkinson's disease patients.

BACKGROUND AND PURPOSE: The Movement Disorder Society sponsored version of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS) is a comprehensive instrument for assessing Parkinson's disease (PD). The present study was aimed at determining the relationships between MDS-UPDRS components and health-related quality of life (HRQoL) evaluations in PD patients. METHODS: An international, multicenter, cross-sectional study was carried out of 435 PD patients assessed with the MDS-UPDRS, Hoehn and Yahr (HY), Clinical Impression Severity for PD, EQ-5D and PD Questionnaire - eight items (PDQ-8). Spearman's rank correlation coefficients, exploratory factor analysis and multiple linear regression models (dependent variables EQ-5D and PDQ-8) were performed. RESULTS: The participants' age was 66.71 ± 10.32 years (51.5% men). PD duration was 8.52 ± 6.14, and median HY was 2 (range 1-5). The correlation between the EQ-5D index and the MDS-UPDRS ranged from -0.46 (Part IV) to -0.72 (Part II) and for the PDQ-8 index from 0.47 (Part III) to 0.74 (Part II). In multiple regression models with the MDS-UPDRS domains as independent variables, the main determinant for both the EQ-5D index and the PDQ-8 was Part II followed by Part I. After factorial grouping of the cardinal PD manifestations embedded in the MDS-UPDRS Parts III and IV for inclusion into multiple regression models, a factor formed by M-EDL, nM-EDL and fluctuations was the main determinant for both the EQ-5D and PDQ-8 indexes. CONCLUSIONS: The MDS-UPDRS component most tightly related with the HRQoL measures was a combination of motor and non-motor experiences of daily living.

Guidelines for the management of coagulation disorders in patients with cirrhosis.

Coagulation management in the patient with cirrhosis has undergone a significant transformation since the beginning of this century, with the concept of a rebalancing between procoagulant and anticoagulant factors. The paradigm that patients with cirrhosis have a greater bleeding tendency has changed, as a result of this rebalancing. In addition, it has brought to light the presence of complications related to thrombotic events in this group of patients. These guidelines detail aspects related to pathophysiologic mechanisms that intervene in the maintenance of hemostasis in the patient with cirrhosis, the relevance of portal hypertension, mechanical factors for the development of bleeding, modifications in the hepatic synthesis of coagulation factors, and the changes in the reticuloendothelial system in acute hepatic decompensation and acute-on-chronic liver failure. They address new aspects related to the hemorrhagic complications in patients with cirrhosis, considering the risk for bleeding during diagnostic or therapeutic procedures, as well as the usefulness of different tools for diagnosing coagulation and recommendations on the pharmacologic treatment and blood-product transfusion in the context of hemorrhage. These guidelines also update the knowledge regarding hypercoagulability in the patient with cirrhosis, as well as the efficacy and safety of treatment with the different anticoagulation regimens. Lastly, they provide recommendations on coagulation management in the context of acute-on-chronic liver failure, acute liver decompensation, and specific aspects related to the patient undergoing liver transplantation.

Determinants and impact of alexithymia on quality of life in Parkinson's disease.

INTRODUCTION: Alexithymia is a neuropsychiatric symptom conceptualized as difficulty identifying and describing feelings. Although associated with other non-motor symptoms, mainly neuropsychiatric, alexithymia may present as an isolated symptom in persons with Parkinson's Disease (PwP). The objective of the study is to identify determinants of alexithymia and its association with quality of life (QoL) in Parkinson's disease. METHODS: Subjects with Parkinson's disease were recruited. The following instruments were applied: Movement Disorders Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS), Non-Motor Symptoms Scale (NMSS), Montreal Cognitive Assessment (MoCA), Toronto alexithymia scale (TAS-20) and Parkinson's Disease Questionnaire (PDQ-8). Matched healthy controls were screened using TAS-20. Clinical and demographical variables were compared between alexithymic and non-alexithymic. Regression models were used to find determinants of alexithymia. Impact of alexithymia on QoL was estimated with a linear regression model. RESULTS: 98 patients were included. 56.1% PwP and 28.8% controls were alexithymic (p<0.001). Education level (OR 0.86) and NMSS urinary score (OR 1.09) determined alexithymia as well as TAS-20 score. Alexithymia was an independent determinant of QoL. CONCLUSIONS: Alexithymia is a prevalent independent non-motor symptom in PwP with impact on QoL. Low education level and urinary symptoms are important determinants of alexithymia.

Sofosbuvir-velpatasvir in Mexican patients with hepatitis C: A retrospective review.

INTRODUCTION: The sofosbuvir-velpatasvir (SOF/VEL) combination is a direct-acting antiviral therapy that is authorized and available in Mexico, making the performance of a real-world multicenter study that evaluates the sustained virologic response at 12 weeks post-treatment a relevant undertaking. METHODS: A retrospective review of the case records of 241 patients seen at 20 hospitals in Mexico was conducted to assess hepatitis C treatment with the SOF/VEL combination (n = 231) and the sofosbuvir/velpatasvir/ribavirin (SOF/VEL/RBV) combination (n = 10). The primary efficacy endpoint was the percentage of patients that achieved SVR at 12 weeks after the end of treatment. RESULTS: Overall SVR was 98.8% (95% CI 97.35-100%). Only three patients did not achieve SVR, two of whom had cirrhosis and a history of previous treatment with peg-IFN. Of the subgroups analyzed, all the patients with HIV coinfection, three patients with genotype 3, and the patients treated with the SOF/VEL/RBV combination achieved SVR. The subgroups with the lower success rates were patients that were treatment-experienced (96.8%) and patients with F1 fibrosis (95.5%). The most frequent adverse events were fatigue, headache, and insomnia. No serious adverse events were reported. CONCLUSION: Treatments with SOF/VEL and SOF/VEL/RBV were highly safe and effective, results coinciding with those of other international real-world studies.

Relationship between the type and side of motor symptoms with the prevalence of non-motor symptoms in Parkinson's disease.

INTRODUCTION: the relationship between laterality and asymmetry of Parkinson's disease and non-motor dysfunction has been studied mainly from the perspective of cognitive functions, and the few studies that have included other symptoms have mixed reports. The relationship between non-motor symptoms and the type of onset of the disease has not been studied in detail. OBJECTIVE: to analyse the association between the side and type of motor onset and the prevalence of non-motor symptoms. PATIENTS AND METHODS: we included 232 patients diagnosed with Parkinson's disease. Type of onset and the side initially affected were documented. The presence of non-motor symptoms was determined by applying the non-motor symptom questionnaire (NMSQuest). RESULTS: when analysing the side of onset and presence of each non-motor symptom explored, statistically significant differences were found in the frequency of hallucinations (P=0.04) and sleep behaviour disorder (P<0.01) in subjects with right side onset. The motor type of onset differences were not statistically significant. CONCLUSIONS: subjects with right side onset seem to have a higher risk of having hallucinations and sleep behaviour disorders. These symptoms should be intentionally sought in order to provide treatment and improve the patient's quality of life.

Clinical and manometric findings on elderly patients with achalasia.

INTRODUCTION: Data regarding the age impact on the clinical presentation and esophageal motility in adults with idiopathic achalasia are scarce. OBJECTIVE: To asses the clinical and manometric features of elderly patients with idiopathic achalasia. METHODS: The medical charts of 159 patients diagnosed with achalasia were divided into two groups according to the patients' age: ?60 years (n = 123) and >60 years (n = 36). Clinical and manometric findings [esophageal body aperistalsis, basal lower esophageal sphincter (LES) pressure and abnormal LES relaxation] of both groups were compared upon diagnosis. Patients with previous esophageal interventions were excluded. RESULTS: Only chest pain was more common in the ?60 year-old group (51.2% vs. 22.2%, p <0.003). This difference remained when comparing the group of men ≤60 years. Other presenting features (including sex, weight loss, and presence of dysphagia, regurgitation and heartburn) did not differ between the groups. The LES relaxation was incomplete in 70.4% of the cases. No differences on the basal LES pressure, residual LES pressure or the amplitude of the esophageal body contractions between both groups were found. Considering only the classic achalasia cases, symptomatic time before diagnosis was greater in ≤60 years compared with older patients: 24 vs. 12 months (p <0.05), respectively. CONCLUSIONS: These results suggest that chest pain is more common in younger male achalasia patients and residual LES pressure decreases with age.

Sofosbuvir-velpatasvir in Mexican patients with hepatitis C: A retrospective review. / Sofosbuvir-velpatasvir en pacientes mexicanos con hepatitis C: una revisión retrospectiva.

INTRODUCTION: The sofosbuvir-velpatasvir (SOF/VEL) combination is a direct-acting antiviral therapy that is authorized and available in Mexico, making the performance of a real-world multicenter study that evaluates the sustained virologic response at 12 weeks post-treatment a relevant undertaking. METHODS: A retrospective review of the case records of 241 patients seen at 20 hospitals in Mexico was conducted to assess hepatitis C treatment with the SOF/VEL combination (n = 231) and the sofosbuvir/velpatasvir/ribavirin (SOF/VEL/RBV) combination (n = 10). The primary efficacy endpoint was the percentage of patients that achieved SVR at 12 weeks after the end of treatment. RESULTS: Overall SVR was 98.8% (95% CI 97.35-100%). Only three patients did not achieve SVR, two of whom had cirrhosis and a history of previous treatment with peg-IFN. Of the subgroups analyzed, all the patients with HIV coinfection, three patients with genotype 3, and the patients treated with the SOF/VEL/RBV combination achieved SVR. The subgroups with the lower success rates were patients that were treatment-experienced (96.8%) and patients with F1 fibrosis (95.5%). The most frequent adverse events were fatigue, headache, and insomnia. No serious adverse events were reported. CONCLUSION: Treatments with SOF/VEL and SOF/VEL/RBV were highly safe and effective, results coinciding with those of other international real-world studies.

Asociación Mexicana de Hepatología A.C. Clinical guideline on hepatitis B.

Hepatitis B virus (HBV) infection continues to be a worldwide public health problem. In Mexico, at least three million adults are estimated to have acquired hepatitis B (total hepatitis B core antibody [anti-HBc]-positive), and of those, 300,000 active carriers (hepatitis B surface antigen [HBsAg]-positive) could require treatment. Because HBV is preventable through vaccination, its universal application should be emphasized. HBV infection is a major risk factor for developing hepatocellular carcinoma. Semi-annual liver ultrasound and serum alpha-fetoprotein testing favor early detection of that cancer and should be carried out in all patients with chronic HBV infection, regardless of the presence of advanced fibrosis or cirrhosis. Currently, nucleoside/nucleotide analogues that have a high barrier to resistance are the first-line therapies.

Asociación Mexicana de Hepatología A.C. Clinical guideline on hepatitis B. / Asociación Mexicana de Hepatología A.C. Guía Clínica de Hepatitis B.

Hepatitis B virus (HBV) infection continues to be a worldwide public health problem. In Mexico, at least three million adults are estimated to have acquired hepatitis B (total hepatitis B core antibody [anti-HBc]-positive), and of those, 300,000 active carriers (hepatitis B surface antigen [HBsAg]-positive) could require treatment. Because HBV is preventable through vaccination, its universal application should be emphasized. HBV infection is a major risk factor for developing hepatocellular carcinoma. Semi-annual liver ultrasound and serum alpha-fetoprotein testing favor early detection of that cancer and should be carried out in all patients with chronic HBV infection, regardless of the presence of advanced fibrosis or cirrhosis. Currently, nucleoside/nucleotide analogues that have a high barrier to resistance are the first-line therapies.

[Evaluation of non-invasive fibrosis indices in Mexican patients with chronic hepatitis C]. / Evaluación de índices no invasivos de fibrosis en pacientes mexicanos con hepatitis crónica por virus C.

BACKGROUND: Among the many methods proposed to predict the presence of fibrosis in patients with chronic hepatitis C are the indices models obtained from serum biochemical tests, the aspartate aminotransferase-toplatelet ratio index (APRI) and the Forns index (FI). OBJECTIVE: To compare the diagnostic accuracy of the Forns index and APRI for predicting cirrhosis. METHODS: We included 105 patients with chronic hepatitis C and a liver biopsy. The FI and APRI were calculated from the biochemical tests of each patient. Receivers operating characteristic (ROC) curves were calculated to determine the best cutoff to discriminate between cirrhosis (F4), advanced fibrosis (F3-F4), and portal fibrosis (F1) according to the Knodell score. Diagnostic accuracy was assessed by obtaining sensitivity (Sn), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV) for each of the indices. RESULTS: ROC curves showed that the best cutoff for predicting cirrhosis (F4) for the FI is >7.64, with Sn 62.5% and Sp 91.8% (Area under the curve, AUC = 0.881), for advanced fibrosis (F3 - F4) the best cutoff value is >6.93 with Sn 42.9% and Sp 89.6% (AUC = 0.772). An APRI value of >1.74 was the best predictor for F4 with Sn 75% and Sp 82% (AUC = 0.799), and a cutoff value of >1.7 for predicting F3-F4 with Sn 47.6% and Sp 85.4% (AUC = 0.768). CONCLUSIONS: The results confirm the utility of both the FI and APRI for predicting advanced fibrosis and cirrhosis.

Determinants and impact of alexithymia on quality of life in Parkinson's disease.

INTRODUCTION: Alexithymia is a neuropsychiatric symptom conceptualized as difficulty identifying and describing feelings. Although associated with other non-motor symptoms, mainly neuropsychiatric, alexithymia may present as an isolated symptom in persons with Parkinson's Disease (PwP). The objective of the study is to identify determinants of alexithymia and its association with quality of life (QoL) in Parkinson's disease. METHODS: Subjects with Parkinson's disease were recruited. The following instruments were applied: Movement Disorders Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS), Non-Motor Symptoms Scale (NMSS), Montreal Cognitive Assessment (MoCA), Toronto alexithymia scale (TAS-20) and Parkinson's Disease Questionnaire (PDQ-8). Matched healthy controls were screened using TAS-20. Clinical and demographical variables were compared between alexithymic and non-alexithymic. Regression models were used to find determinants of alexithymia. Impact of alexithymia on QoL was estimated with a linear regression model. RESULTS: 98 patients were included. 56.1% PwP and 28.8% controls were alexithymic (p<0.001). Education level (OR 0.86) and NMSS urinary score (OR 1.09) determined alexithymia as well as TAS-20 score. Alexithymia was an independent determinant of QoL. CONCLUSIONS: Alexithymia is a prevalent independent non-motor symptom in PwP with impact on QoL. Low education level and urinary symptoms are important determinants of alexithymia.

The Mexican consensus on the treatment of hepatitis C. / Consenso Mexicano para el Tratamiento de la Hepatitis C.

The aim of the Mexican Consensus on the Treatment of HepatitisC was to develop clinical practice guidelines applicable to Mexico. The expert opinion of specialists in the following areas was taken into account: gastroenterology, infectious diseases, and hepatology. A search of the medical literature was carried out on the MEDLINE, EMBASE, and CENTRAL databases through keywords related to hepatitisC treatment. The quality of evidence was subsequently evaluated using the GRADE system and the consensus statements were formulated. The statements were then voted upon, using the modified Delphi system, and reviewed and corrected by a panel of 34 voting participants. Finally, the level of agreement was classified for each statement. The present guidelines provide recommendations with an emphasis on the new direct-acting antivirals, to facilitate their use in clinical practice. Each case must be individualized according to the comorbidities involved and patient management must always be multidisciplinary.

[Frequency of single nucleotide polymorphisms and alpha-synuclein haplotypes associated with sporadic Parkinson's disease in the Mexican population]. / Frecuencia de polimorfismos de nucleotido unico y haplotipos de alfa-sinucleina asociados con la enfermedad de Parkinson esporadica en poblacion mexicana.

INTRODUCTION: Parkinson's disease (PD) is a common neurodegenerative disease which begins in adulthood. Its incidence in Mexico is estimated to be 40-50 cases per 100,000 inhabitants/year and is the fourth reason for medical care in the National Institute of Neurology and Neurosurgery. The protein alpha-synuclein, SNCA, plays a key role in the pathology of PD, and its polymorphisms have been associated with an increased risk of developing the disease. AIM: To evaluate the risk of PD represented by the polymorphisms rs2619364, rs2619363, rs2736990, rs7684318, rs17016074, rs356219, rs356220 and rs356203 of SNCA in a sample of Mexican subjects. SUBJECTS AND METHODS: Altogether 171 patients diagnosed with PD and 171 gender- and age-paired controls were assessed by means of real-time polymerase chain reaction, and a statistical analysis was performed to determine the association between the polymorphisms and the disease. RESULTS: The SNCA variants rs356220, rs356203, rs7684318 and rs2736990 were associated with the disease and form two haplotypes with a high risk of developing sporadic PD in the Mexican population. CONCLUSIONS: Variations in SNCA are a risk factor for the development of PD and can act as specific genetic biomarkers as a diagnostic support tool in sporadic PD for Mexican mestizo patients.

TITLE: Frecuencia de polimorfismos de nucleotido unico y haplotipos de alfa-sinucleina asociados con la enfermedad de Parkinson esporadica en poblacion mexicana.Introduccion. La enfermedad de Parkinson (EP) es una entidad neurodegenerativa comun de inicio en la etapa adulta. Su incidencia en Mexico se estima en 40-50 casos por 100.000 habitantes/año y constituye la cuarta causa de atencion medica en el Instituto Nacional de Neurologia y Neurocirugia. La proteina alfa-sinucleina, SNCA, es clave en la patologia de la EP y sus polimorfismos se han asociado a un riesgo aumentado de desarrollarla. Objetivo. Evaluar el riesgo que representan los polimorfismos rs2619364, rs2619363, rs2736990, rs7684318, rs17016074, rs356219, rs356220 y rs356203 de SNCA en una muestra de sujetos mexicanos para la EP. Sujetos y metodos. Se evaluaron 171 pacientes con diagnostico de EP y 171 controles pareados por sexo y edad mediante reaccion en cadena de la polimerasa en tiempo real, y se realizo un analisis estadistico para determinar la asociacion de los polimorfismos con la enfermedad. Resultados. Las variantes rs356220, rs356203, rs7684318 y rs2736990 de SNCA estan asociadas a la enfermedad y forman dos haplotipos de riesgo elevado para desarrollar EP esporadica en la poblacion mexicana. Conclusiones. Las variaciones en SNCA son un factor de riesgo para desarrollar EP y pueden ser biomarcadores geneticos especificos para pacientes mestizos mexicanos como herramienta de apoyo diagnostico en la EP esporadica.