Retrospective pharmacogenetic analysis of a pediatric patient under anticoagulant treatment: Clinical case / Análisis farmacogenético retrospectivo de una paciente pediátrica en tratamiento anticoagulante: caso clínico.

We present the clinical case of a 10-year-old patient diagnosed with dilated cardiomyopathy who registered INR values above 10 upon receiving standard doses of acenocoumarol, as well as other values reported as uncoagulable, forcing the discontinuation and restart of treatment more than once. Expected and stable INR levels were achieved after more than 30 days of treatment, surprisingly with half the recommended dose for a patient of her age and weight. We decided to conduct a retrospective pharmacogenomic analysis including nucleotide genetic polymorphisms (SNPs) with different degrees of association with the dose/response to antivitamin K (AVK) drugs: rs2108622 (gene CYP4F2), rs9923231, rs7294 (gene VKORC1), rs1799853, and rs1057910 (CYP2C9 gene) using TaqMan® RT-PCR. The patient was homozygous for rs9923231 (VKORC1) and heterozygous for rs2108622 (CYP4F2),a genetic profile strongly associated with a requirement of lower AVK doses as shown by national and international evidence. In conclusion, the pharmacogenetic analysis confirmed that this patient's genetic conditions, involving low expression of the VKA therapeutic target, required a lower dose than that established in clinical protocols as recommended by the Food and Drug Administration (FDA) and the PharmGKB® for coumarin drugs. A previous genotypic analysis of the patient would have allowed reaching the therapeutic range sooner, thus avoiding potential bleeding risks. This shows the importance of pharmacogenetic analyses for highly variable treatments with a narrow therapeutic range.

Se presenta el caso clínico de una paciente de 10 años diagnosticada con miocardiopatía dilatada, quien registró valores en el índice internacional normalizado (International Normalized Ratio, INR) superiores a 10 con la dosis estándar de acenocumarol, además de otros valores que indicaban el estado incoagulable, lo que obligó a suspender y reiniciar el tratamiento en varias ocasiones. Después de más de 30 días de tratamiento, sorprendentemente se lograron los niveles esperados y estables en el INR con la mitad de a dosis recomendada para una paciente de su edad y peso. Se decidió hacer un análisis farmacogenético retrospectivo del caso mediante RT-PCR con sondas TaqMan™ que incluyó cinco polimorfismos de un solo nucleótido y distinto grado de asociación con la dosis-respuesta a los fármacos antivitamínicos K (AVK): rs2108622 (gen CYP4F2), rs9923231, rs7294 (gen VKORC1), rs1799853 y rs1057910 (gen CYP2C9). La paciente resultó ser homocigota para el rs9923231 (VKORC1) y heterocigota para el rs2108622 (CYP4F2). Se ha evidenciado a nivel nacional e internacional que este perfil genético está fuertemente asociado con una necesidad de dosis menores de antivitamínicos K. En conclusión, el análisis farmacogenético confirmó que la condición genética de la paciente, la cual conlleva una baja expresión de la enzima VKORC1 (blanco terapéutico de los antivitamínicos K), hacía predecible la necesidad de una dosis menor a la establecida según los protocolos clínicos recomendados por la Food and Drug Administration (FDA) y PharmGKB™ para los fármacos cumarínicos.

Análisis farmacogenético retrospectivo de una paciente pediátrica en tratamiento anticoagulante: caso clínico / Retrospective pharmacogenetic analysis of a pediatric patient under anticoagulant treatment: Clinical case

Se presenta el caso clínico de una paciente de 10 años diagnosticada con miocardiopatía dilatada, quien registró valores en el índice internacional normalizado (International Normalized Ratio, INR) superiores a 10 con la dosis estándar de acenocumarol, además de otros valores que indicaban el estado incoagulable, lo que obligó a suspender y reiniciar el tratamiento en varias ocasiones. Después de más de 30 días de tratamiento, sorprendentemente se lograron los niveles esperados y estables en el INR con la mitad de la dosis recomendada para una paciente de su edad y peso.Se decidió hacer un análisis farmacogenético retrospectivo del caso mediante RT-PCR con sondas TaqMan™ que incluyó cinco polimorfismos de un solo nucleótido y distinto grado de asociación con la dosis-respuesta a los fármacos antivitamínicos K (AVK): rs2108622 (gen CYP4F2), rs9923231, rs7294 (gen VKORC1), rs1799853 y rs1057910 (gen CYP2C9). La paciente resultó ser homocigota para el rs9923231 (VKORC1) y heterocigota para el rs2108622 (CYP4F2). Se ha evidenciado a nivel nacional e internacional que este perfil genético está fuertemente asociado con una necesidad de dosis menores de antivitamínicos K.En conclusión, el análisis farmacogenético confirmó que la condición genética de la paciente, la cual conlleva una baja expresión de la enzima VKORC1 (blanco terapéutico de los antivitamínicos K), hacía predecible la necesidad de una dosis menor a la establecida según los protocolos clínicos recomendados por la Food and Drug Administration (FDA) y PharmGKB™ para los fármacos cumarínicos. El análisis genotípico previo de la paciente hubiese permitido alcanzar el rango terapéutico más prontamente, evitando potenciales riesgos de hemorragia, lo que demuestra la importancia de los análisis farmacogenéticos en tratamientos de gran variabilidad y estrecho rango terapéutico.

Abstract We present the clinical case of a 10-year-old patient diagnosed with dilated cardiomyopathy who registered INR values above 10 upon receiving standard doses of acenocoumarol, as well as other values reported as uncoagulable, forcing the discontinuation and restart of treatment more than once. Expected and stable INR levels were achieved after more than 30 days of treatment, surprisingly with half the recommended dose for a patient of her age and weight. We decided to conduct a retrospective pharmacogenomic analysis including nucleotide genetic polymorphisms (SNPs) with different degrees of association with the dose/response to antivitamin K (AVK) drugs: rs2108622 (gene CYP4F2), rs9923231, rs7294 (gene VKORC1), rs1799853, and rs1057910 (CYP2C9 gene) using TaqMan® RT-PCR. The patient was homozygous for rs9923231 (VKORC1) and heterozygous for rs2108622 (CYP4F2), a genetic profile strongly associated with a requirement of lower AVK doses as shown by national and international evidence. In conclusion, the pharmacogenetic analysis confirmed that this patient's genetic conditions, involving low expression of the VKA therapeutic target, required a lower dose than that established in clinical protocols as recommended by the Food and Drug Administration (FDA) and the PharmGKB® for coumarin drugs. A previous genotypic analysis of the patient would have allowed reaching the therapeutic range sooner, thus avoiding potential bleeding risks. This shows the importance of pharmacogenetic analyses for highly variable treatments with a narrow therapeutic range.

Positive Association of Ascorbate and Inverse Association of Urate with Cognitive Function in People with Parkinson's Disease.

Oxidative stress is thought to contribute to the aetiology of neurological disorders such as Parkinson's disease. Ascorbate (vitamin C) is a potent antioxidant and is associated with neurological and cognitive function. In this study we assessed the ascorbate status of a cohort of people with Parkinson's disease (n = 215), aged 50-90 years, compared with a cohort of age matched healthy controls (n = 48). The study sample's cognitive status ranged from normal to mild cognitive impairment and dementia. There was no difference between the Parkinson's disease and healthy control groups with respect to mean ascorbate status, however, a higher proportion of participants with Parkinson's disease had hypovitaminosis C (i.e., <23 µmol/L) compared with healthy controls (20% vs. 8%, respectively). Within the Parkinson's disease group, Montreal Cognitive Assessment (MoCA) scores correlated positively with ascorbate concentrations, with higher ascorbate status associated with better cognitive function (r = 0.14, p = 0.045). Participants with hypovitaminosis C had significantly lower MoCA scores relative to participants with ascorbate concentrations >23 µmol/L (p = 0.014). Ascorbate concentrations were significantly lower in the cognitively impaired subgroup compared with the normal cognition subgroup in the Parkinson's disease cohort (p = 0.03). In contrast, urate showed an inverse correlation with cognitive function (r = -0.19, p = 0.007), with higher urate concentrations observed in the cognitively impaired subgroup compared with the normal cognition subgroup (p = 0.015). There was an inverse association between ascorbate status and urate concentrations (r = -0.15, p = 0.017). Plasma protein carbonyls, a measure of systemic oxidative stress, were not significantly different between the Parkinson's disease cohort and healthy controls, and there was no association with cognitive function (r = 0.09, p = 0.19) or with ascorbate status (r = -0.05, p = 0.45). Overall, our study showed ascorbate status was positively associated with cognitive function in Parkinson's disease, suggesting that longitudinal studies investigating the temporal sequence of cognitive decline and ascorbate status are warranted.

Functionally Significant Coumarin-Related Variant Alleles and Time to Therapeutic Range in Chilean Cardiovascular Patients.

Despite the development of new oral agents over the last decade, vitamin K antagonists (VKAs) remain the most widely used anticoagulants for treating and preventing thromboembolism worldwide. In Chile, the Ministry of Health indicates that acenocoumarol should be used in preference to any other coumarin. Complications of inappropriate dosing are among the most frequently reported adverse events associated with this medication. It is well known that polymorphisms in pharmacokinetic and pharmacodynamic proteins related to coumarins (especially warfarin) influence response to these drugs. This work analyzed the impact of CYP2C19*2 (rs4244285), CYP1A2*1F (rs762551), GGCx (rs11676382), CYP2C9*2 (rs1799853), CYP2C9*3 (rs1057910), CYP4F2 (rs2108622), VKORC1 (rs9923231), VKORC1 (rs7294), CYP3A4*1B (rs2740574), and ABCB1 (rs1045642) polymorphisms on time to therapeutic range for oral anticoagulants in 304 Chilean patients. CYP2C9*3 polymorphisms were associated with time to therapeutic range for acenocoumarol in Chilean patients, and the CYP4F2 TT genotype, MDR1 A allele, CYP1A2 A allele, and CYP3A4T allele are promising variants that merit further analysis. The presence of polymorphisms explained only 4.1% of time to therapeutic range for acenocoumarol in a multivariate linear model. These results improve our understanding of the basis of ethnic variations in drug metabolism and response to oral anticoagulant therapy. We hope that these findings will contribute to developing an algorithm for VKA dose adjustment in the Chilean population in the near future, decreasing the frequency of stroke, systemic embolism, and bleeding-related adverse events.

A Pharmacogenetically Guided Acenocoumarol Dosing Algorithm for Chilean Patients: A Discovery Cohort Study.

BACKGROUND: Vitamin K antagonists (VKA) are used as prophylaxis for thromboembolic events in patients with cardiovascular diseases. The most common VKA are warfarin and acenocoumarol. These drugs have a narrow therapeutic margin and high inter-individual response variability due to clinical and pharmacogenetic variables. OBJECTIVE: The authors aim to develop an algorithm comprised of clinical and genetic factors to explain the variability in the therapeutic dose of acenocoumarol among Chilean patients. METHODOLOGY: DNA was obtained from 304 patients as a discovery cohort with an international normalized ratio (INR) range of 2.0-3.0. The non-genetic (demographic and clinical) variables were also recorded. Genotype analyses were performed using real-time PCR for VKORC1 (rs9923231), VKORC1 (rs7294), GGCx (rs11676382), CYP4F2 (rs2108622), ABCB1 (rs1045642), CYP2C9*2 (rs1799853), ApoE (rs429358), and CYP2C9*3 (rs1057910). RESULTS: The clinical variables that significantly influenced the weekly therapeutic dose of VKA were age, sex, body mass index (BMI), and initial INR, collectively accounting for 19% of the variability, and the genetic variables with a significant impact were VKORC1 (rs9923231), CYP2C9*2 (rs1799853), and CYP2C9*3 (rs1057910), explaining for another 37% of the variability. CONCLUSION: We developed an algorithm that explains 49.99% of the variability in therapeutic VKA dosage in the Chilean population studied. Factors that significantly affected the dosage included VKORC1, CYP2C9*2, and CYP2C9*3 polymorphisms, as well as age, sex, BMI, and initial INR.

Anticoagulation Management With Coumarinic Drugs in Chilean Patients.

Warfarin and acenocoumarol are used in various cardiovascular disorders to improve the prognosis of patients with thromboembolic disease. However, there is a lack of substantial efficacy and safety data on antithrombotic prophylaxis in several countries, particularly in Latin America. The aim of this study was to provide information about the efficacy of anticoagulants in Chilean patients. Data were collected from databases of the Western Metropolitan Health Service, Santiago, Chile. We identified 6280 records of patients receiving anticoagulant treatment. The three most common diagnoses were rhythm disorder (43.7%), venous thrombosis (22%), and valvular prosthesis (10.7%). The majority of patients (98.5%) received acenocoumarol while 1.5% of patients received warfarin, at weekly therapeutic doses of 13.6 mg and 30.4 mg, respectively. For total diagnoses, the median time in the therapeutic range was 50%. However, better results, 66.7%, were observed when a telemedicine strategy was used only in Santiago Province. Our findings emphasize that in Chile, where the number of patients receiving anticoagulant treatment increases every year, telemedicine, by committed teams, improves the use of oral anticoagulants and is able to increase quality indicators of anticoagulant treatment care.