Polimorfismo do gene CYP2D6 1846 G/A em associação com o Acidente Vascular Encefálico/Aneurisma em uma população do Distrito Federal (Brasil) / CYP2D6 1846 G/A gene polymorphism in association with Hemorrhagic Stroke/Aneurysm in patients from the Federal District (Brazil)

Objetivo: Investigar uma possível associação do gene CYP2D6 1846 G/A em pacientes que possuem AVEH/Aneurisma, residentes no Distrito Federal (Brasil) além de cruzar as informações obtidas com as manifestações clinicas e o prognóstico. Método: Tratou-se de um estudo caso-controle de base populacional, envolvendo 81 casos com AVEH e/ou Aneurisma. Para a genotipagem dessas amostras utilizou-se a técnica laboratorial PCR-RFLP e adotou-se o nível de significância de 5%. Resultados: Ao associar as frequências genotípicas e alélicas em relação ao AVEH/Aneurisma, percebeu-se que não houve diferença estatística. Em relação à média de glicemia, participantes com genótipo GG, apresentavam índices elevados desse marcador no grupo caso quando comparado ao grupo controle. Conclusão: A presença do polimorfismo CYP2D6 1846 G/A deve ser amplamente estudada em pesquisas futuras, pois é necessário esclarecer se tais polimorfismos representam associações ao AVEH/Aneurisma.

Objective: To investigate a possible association of the CYP2D6 1846 G/A gene in HS/aneurysm patients residing in the Federal District (Brazil), as well as to crosscheck the information obtained with clinical manifestations and prognosis. Method: The investigation was a population-based case-control study involving 81 cases with HS/aneurysm. The samples genotyping employed the PCR-RFLP technique with a significance level of 5%. Results: The attempt to associate genotypic and allelic frequencies to the HVA/Aneurysm resulted in no statistical difference. Nevertheless, in patients with the GG genotype and hypertension, the risk for HS increased 44 times. Participants with GG genotype also had statistically higher glycemia mean levels in the case group. Conclusion: The presence of the CYP2D6 1846 G/A polymorphism should be extensively, as it is necessary to clarify whether such polymorphisms represent associations with HS and Intracerebral Aneurysm.

Correlation between CYP2D6 polymorphism and risperidone metabolism in schizophrenic patients / 中华检验医学杂志

Objective To investigate the effect of CYP2D6 gene polymorphism on risperidone (RISP) metabolism in schizophrenic patients. Methods CYP2D6 allele polymorphisms including*10,*4,*41 and *2 was detected by real-time fluorescent PCR in 120 schizophrenic patients who have taken risperidone continually. Alleles without SNP mutations were classified as wild-type (WT). At the same time, serum risperidone and 9-hydroxyrisperidone concentration of all patients were detected by mass spectrometric analysis. Some samples were selected for DNA sequencing of CYP2D6*10, which is the most common CYP2D6 allele in Oriental population. The 120 patients were divided into three groups according to their allele variants. Group 1 was defined as carriers of two functional alleles, group 2 was defined as carriers of one defective allele, group 3 was defined as carriers of two defective alleles. Genotype distributions, alleles frequencies, RISP, 9-oh-RISP, RISP+9-OH-RISP, 9-oh-RISP/RISP among three groups were calculated.Results Group 1 amount to 23 cases including 13 cases of WT/WT, 7 cases of*2/*2, 3 cases of WT/*2. Group 2 amount to 51 cases, including 38 cases of WT/*10, 8 cases of *2/*10, 1 case of *2/*41, 4 cases of WT/*41. Group 3 amount to 46 cases, including 44 cases of *10/*10, 2 cases of *10/*41. The*4 allele was not detected. The allele frequency of WT, *2, *10 and *41 was 29.6％, 10.8％, 56.7％ and 2.9％, respectively. The 9-hydroxyrisperidone/risperidone-ratio of three groups were 15.24±5.77, 11.06±4.56 and 2.39 ± 1.06, respectively. There was a significant difference in 9-hydroxyrisperidone/risperidone-ratio between Group 3 and the first two groups (P<0.001). Conclusions The frequency of *10 allele was the highest among the subjects. The frequency of WT and*2 allele was over 95％in the population. Individuals carrying one defective allele of CYP2D6 will decrease the rate of risperidone metabolism slightly, while individuals carrying two defective alleles of CYP2D6 may decrease the rate of risperidone metabolism significantly.

Impacts of cytochrome P450 2D6 (CYP2D6) genetic polymorphism in tamoxifen therapy for breast cancer impactos do polimorfismo genético do citocromo P450 2D6 (CYP2D6) na terapia com tamoxifeno para câncer de mama

Abstract Tamoxifen (TMX) is the main drug used both in pre and postmenopausal women as adjuvant treatment for hormone receptor-positive breast cancer. An important barrier to the use of TMXis the development ofdrug resistance causedby molecular processes related to genetic and epigenetic mechanisms, such as the actions of cytochrome P450 2D6 (CYP2D6) polymorphisms and of its metabolites. The present study aimed to review recent findings related to the impact of CYP2D6 polymorphisms and how they can affect the results of TMX in breast cancer treatment. The keywords CYP2D6, tamoxifen, and breast cancer were searched in the PubMed, Scopus, The Cochrane Library, Scielo, and Bireme databases. Studies related to other types of neoplasms or based on other isoenzymes from cytochrome P450, but not on CYP2D6, were excluded. The impact of CYP2D6 polymorphisms in the TMX resistance mechanism remains unclear. The CYP2D6 gene seems to contribute to decreasing the efficacy of TMX, while the main mechanism responsible for therapy failure, morbidity, and mortality is the progression of the disease.

Resumo Otamoxifeno é a principal drogaque pode ser utilizada comotratamentohormonal adjuvante empacientesportadoras de câncer demamareceptor hormonal positivotanto na pré- quanto na pós-menopausa.Umadasmaiores barreirasemseu uso é o desenvolvimento de resistência medicamentosa causada por meio de processos moleculares relacionados a mecanismos genéticos e epigenéticos, como a ação dos polimorfismos do gene citocromo P450 2D6 (CYP2D6) e seus metabólitos.Opresente estudo busca revisar as descobertas recentes acerca dos impactos dos polimorfismos do gene CYP2D6 e de como eles podem afetar os resultados do tamoxifeno na terapêutica do câncer de mama. As palavras-chave CYP2D6, tamoxifeno e câncer de mama foram buscadas nas bases de dados Pubmed, Scopus, The Cochrane Library, Scielo e Bireme. Estudos relacionados com outros tipos de câncer ou relacionados a outras isoenzimas do citocromo P450 que não o CYP2D6 foram excluídos. O impacto do polimorfismo do CYP2D6 nos mecanismos de resistência ao tamoxifeno permanecem controversos. O gene CYP2D6 parece reduzir a eficácia do TMX; entretanto, os principais fatores associados a falha terapêutica são morbimortalidade e a progressão da doença

Hiccup Due to Aripiprazole Plus Methylphenidate Treatment in an Adolescent with Attention Deficit and Hyperactivity Disorder and Conduct Disorder: A Case Report

Our case had hiccups arising in an adolescent with the attention deficit and hyperactivity disorder (ADHD) and conduct disorder (CD) after adding aripiprazole treatment to extended-release methylphenidate. Actually, antipsychotics are also used in the treatment of hiccups, but studies suggest that they can cause hiccups as well. Within 12 hours of taking 2.5 mg aripiprazole added to extended-release methylphenidate at a dose of 54 mg/day, 16-year-old boy began having hiccups in the morning, which lasted after 3–4 hours. As a result, aripiprazole was discontinued and methylphenidate was continued alone because we could not convince the patient to use another additional drug due to this side effect. Subsequently, when his behavior got worsened day by day, his mother administered aripiprazole alone again at the dose of 2.5 mg/day at the weekend and continued treatment because hiccup did not occur again. But when it was administered with methylphenidate on Monday, hiccup started again next morning and lasted one hour at this time. In conclusion, we concluded that concurrent use of methylphenidate and aripiprazole in this adolescent led to hiccups.

Elección del mejor antidepresivo en pacientes con cáncer de mama en tratamiento con tamoxifeno: revisión de la evidencia básica y clínica / Antidepressants agents in breast cancer patients using tamoxifen: review of basic and clinical evidence

Tamoxifen (Tmf), is a standard of care for women with estrogen receptor positive (ER+) breast cancer. Endoxifen is a Tmf metabolite generated by cytochrome P450 2D6 (CYP2D6). Antidepressive agents (AD) are often prescribed to women with breast cancer not only for depression, but also for anxiety and hot flashes. Some AD are substrates or inhibitors of the Tmf metabolic pathway. Therefore there may be interactions when Tmf and AD are prescribed simultaneously. Oncologic protection afforded by Tmf may become less effective or null when AD are indicated, especially in poor metabolizing patients. We performed an update of the literature about the criteria for choosing AD in women receiving Tmf. Tricyclic AD, paroxetine and fluoxetine should be avoided in patients receiving Tmf, because they are strong inhibitors of CYP2D6. Bupropion, duloxetine and sertraline are only moderate inhibitors of the cytochrome and are not contraindicated. Citalopram, desvenlafaxine, escitalopram, milnacipran and venlafaxine are recommended, because they do not influence the metabolism and clinical efficacy of Tmf and have fewer drug interactions. However, other additional pharmacological and clinical issues should be considered when choosing an antidepressant in women with breast cancer.

Genetic Polymorphism of CYP2D6 and Clomiphene Concentrations in Infertile Patients with Ovulatory Dysfunction Treated with Clomiphene Citrate

CYP2D6 is primarily responsible for the metabolism of clomiphene citrate (CC). The purpose of the present study was to investigate the relationship between CYP2D6 genotypes, concentrations of CC and its major metabolites and drug response in infertility patients. We studied 42 patients with ovulatory dysfunction treated with only CC. Patients received a dose of 100 mg/day CC on days 3-7 of the menstrual cycle. CYP2D6 genotyping and measurement of CC and the major metabolite concentrations were performed. Patients were categorized into CC responders or non-responders according to one cycle response for the ovulation. Thirty-two patients were CC responders and 10 patients were non-responders with 1 cycle treatment. The CC concentrations were highly variable within the same group, but non-responders revealed significantly lower (E)-clomiphene concentration and a trend of decreased concentrations of active metabolites compared to the responders. Nine patients with intermediate metabolizer phenotype were all responders. We confirmed that the CC and the metabolite concentrations were different according to the ovulation status. However, our results do not provide evidence for the contribution of CYP2D6 polymorphism to either drug response or CC concentrations.

Relationship between CYP2D6*10 gene polymorphism and metoprolol therapeutic effect for hypertension / 心血管康复医学杂志

Objective: To study the relationship between CYP2D6*10 gene polymorphism and metoprolol therapeutic effect for hypertension. Methods: A total of 60 patients with essential hypertension (EH) received metoprolol 47.5mg/d for 3d. After 3d the plasma metoprolol concentration after oral 2h was measured. Polymorphism of CYP2D6*10 gene was detected by PCR-RFLP. According to results of gene detection, the patients were divided into CC genotype group (wild type homozygote, fast metabolism type, n=14), CT genotype group (heterozygous mutation, intermediate metabolism type, n=25) and TT genotype group (homozygous mutation, slow metabolism, n=19). Metoprolol dosage was adjusted according to CYP2D6*10 genotype. After one week, plasma concentration of metoprolol after oral 2h was measured again, and mean heart rate and blood pressure were measured before and after gene-directed therapy. Results: Before gene-directed therapy, compared with CC and CT group there was significant increase in plasma concentration of metoprolol [(26.57±19.40) ng/ml vs. (23.88±12.86) ng/ml vs. (64.74±32.94) ng/ml, P0.05 all; Compared with before gene-directed therapy, there was significant increase in plasma concentration of metoprolol, and significant decrease in mSBP, mDBP and mHR in CC group (P0.05). Conclusion: CYP2D6*10 gene polymorphism affects metoprolol metabolism and its therapeutic effect on hypertension, gene-directed therapy can significantly improve drug therapeutic effect and reach ideal therapeutic goal in short time.

Importância do CYP2D6 em usuárias de tamoxifeno no câncer de mama / Importance of CYP2D6 in users of tamoxifen in breast cancer

O tamoxifeno é a terapia hormonal mais usada nas últimas três décadas no tratamento do câncer de mama (CM) hormônio-dependente e, mais recentemente, na prevenção de CM em mulheres de todas as idades. Sua atividade farmacológica depende da sua bioativação pelo citocromo P450 2D6. Os resultados clínicos da terapia com tamoxifeno são influenciados por diversos fatores, incluindo o genótipo metabolizador CYP2D6, aderência ao tratamento e o uso de comedicações inibidoras, como os antidepressivos. Vários estudos sugerem que mulheres que transportam uma ou duas variantes alélicas do CYP2D6, que codificam enzimas com atividade reduzida ou nula podem ter um pior desfecho clínico quando tratadas com terapia adjuvante com tamoxifeno em comparação às mulheres portadoras de dois alelos com função normal. Este artigo de revisão visa resumir os dados disponíveis na literatura sobre a interação do genótipo CYP2D6 e os resultados clínicos de mulheres em terapia hormonal com tamoxifeno

Tamoxifen is a hormone therapy used over the past three decades in the treatment of breast cancer hormone-dependent and, more recently, the prevention of breast cancerin women of all ages. Its pharmacological activity depends on its bioactivation by cytochrome P450 2D6. Clinical results of therapy with tamoxifen are influenced by several factors, including CYP2D6 metabolizer genotype, treatment adherence and use co-inhibitory drugs such as antidepressants. Multiple studies suggest that women who carry one or two variant CYP2D6 alleles that encode enzymes with null or reduced activity may have an inferior breast cancer outcome when treated with tamoxifen in the adjuvant setting compared to women carrying two alleles encoding an enzyme with normal activity. This review article will summarize the available published breast cancer data on the interaction between CYP2D6 genotype and clinical outcomes in women on hormone therapy with tamoxifen

Association between Genetic Polymorphisms of CYP2D6 and Outcomes in Breast Cancer Patients with Tamoxifen Treatment

The aim of the study was to evaluate the association between genetic polymorphisms of CYP2D6 and outcomes in breast cancer patients with tamoxifen treatment. We evaluated the CYP2D6 genetic polymorphisms in 766 breast cancer patients. Among them, 110 patients whose samples were prospectively collected before surgery and treated with tamoxifen were included to evaluate the association between CYP2D6 and outcomes. The genotypes of CYP2D6 were categorized as extensive metabolizer (EM), intermediate metabolizer (IM), and poor metabolizer (PM) according to the activity score. The clinicopathologic features of 110 patients were not significantly different among the three groups except for the T-stage and nodal status. The high T-stage and axillary metastasis were more frequent in the PM group. While recurrence-free and overall survival in the PM group was poorer than the other groups, there was no significant difference between the EM and the IM group. The difference between the PM and the other groups on univariate analysis disappeared on multivariate analysis. These conflicting results suggest that the clinical value of CYP2D6 polymorphisms is still unclear and more large-sized and comprehensively designed trials are necessary.

Determinação da frequência de polimorfismos de cyp2d6 em mulheres brasileiras e revisão de literatura / Determination of the frequency of CYP2D6 polymorphisms in Brazilian women and literature review

O tamoxifeno (TMX),consagrado como terapia padrão no tratamento de pacientes portadoras de câncer de mama com receptores hormonais positivos, é convertido por metabolização primária e secundária no metabólito endoxifeno, que apresenta afinidade muito maior pelos receptores hormonais e é o maior responsável pelos efeitos antitumorais desta droga. A biotransformação do TMX em endoxifeno é dependente da subunidade 2D6 do citocromo P-450 (CYP2D6), cujo gene apresenta inúmeros polimorfismos que reduzem a atividade metabólica dessa via biológica, resultando em menores níveis de seu produto ativo e, possivelmente, da resposta terapêutica ao uso do TMX. Objetivo: O objetivo deste estudo foi determinar a frequência dos polimorfismos CYP2D6*3, *4, *5, *6 e *10 e dos fenótipos de metabolização da droga TMX em pacientes portadoras de câncer de mama atendidas pelos autores no Centro de Oncologia do Hospital Sírio Libanês (HSL), além de revisar os dados sobre este tema disponíveis na literatura. Métodos: Amostras de sangue periférico de 30 pacientes foram enviadas a laboratório de referência para pesquisa dos polimorfismos descritos de CYP2D6 pela técnica de reação em cadeia da polimerase e digestão por enzimas de restrição (PCR-RFLP). Resultados: Os resultados mostraram heterozigose para polimorfismo CYP2D6*4 e *10 em 33 e 38% das mulheres, respectivamente. Utilizando a classificação de fenótipos de metabolização de TMX previamente descrita determinamos que 27% das mulheres avaliadas foram categorizadas com perfil de metabolização intermediária da droga, e 3% como metabolizadoras pobres, as quais, segundo dados atuais, parecem estar duas vezes mais sujeitas a desenvolverem recorrência de câncer de mama durante tratamento com TMX. Foi documentada uma elevada e inesperada prevalência de heterozigose do polimorfismo *10 na população estudada. Conclusões: Estudos prospectivos estão em andamento, visando definir o papel do perfil dos polimorfismos de CYP2D6 na escolha...

Tamoxifen (TMX), established as standard therapy in treating patients with breast cancer with hormone receptor positive, is converted by metabolism in primary and secondary metabolite endoxifeno, which has much higher affinity for hormone receptors and is most responsible the antitumor effects of this drug. Biotransformation of TMX in endoxifeno 2D6 is dependent on the subunit of cytochrome P-450 (CYP2D6), whose gene has many polymorphisms that reduce the metabolic activity of this biological pathway, resulting in lower levels of its active product, and possibly therapeutic response to use of TMX. Objective: The objective of this study was to determine the frequency of CYP2D6 polymorphisms * 3, * 4, * 5, * 6 and * 10 and phenotypes of drug metabolizing TMX in patients with breast cancer treated by the authors at the Centre for Oncology Syrian Lebanese Hospital (HSL), and review the data on this subject available in the literature. Methods: Blood samples from 30 patients were sent to reference laboratory for research of CYP2D6 polymorphisms described the technique of polymerase chain reaction and restriction enzyme digestion (PCR-RFLP). Results: Results showed heterozygosity for polymorphic CYP2D6 * 4 and * 10 in 33 women and 38% respectively. Using the classification of phenotypes of metabolism of TMX described previously determined that 27% of the women studied were categorized with a profile of intermediate metabolites of the drug, and 3% as poor metabolizers, which, according to current data seem to be two times more likely to develop recurrence of breast cancer during treatment with TMX. It was documented and an unexpected high prevalence of heterozygous * 10 polymorphism in the population. Conclusions: Prospective studies are underway, aimed at defining the role of the profile of CYP2D6 polymorphisms on the choice of strategy hormonal therapy in women with breast cancer.

CYP2D6 gene G4268C single nucleotide polymorphism and genetic susceptibility to lung cancer / 第二军医大学学报

Objective: To evaluate the relation between the single nucleotide polymorphism of CYP2D6 gene G4268C and the genetic susceptibility to lung cancer. Methods: A case-control study was conducted among 118 lung cancer patients and 118 control subjects (matched for sex, age) to investigate the role of CYP2D6 gene G4268C polymorphism in lung cancer; PCR-RFLP was used to identify the genotypes of polymorphism. Logistic regression was used to analyze the relationship between polymorphism and genetic susceptibility to lung cancer. Results: The frequency of G4268-C mutation in case and control group were 69.49% and 75.00%, respectively. Non-C4268/C genotype (including G4268/G and G4268/C genotype) was correlated to the high risk of lung cancer, with OR adjusted by gender, age and smoking being 1.80 (95% CI=1.06-3.06), especially to lung adenocarcinoma (OR being 2.95 [95% CI=1.39-6.23]). After stratified analysis of smoking history and adjusting by gender and age, it was revealed that non-C4268/C genotype was associated with significantly increased risk of lung cancer in non-smokers and light-smokers groupq with OR = 2.12 (95% CI = 1.03-4. 36) and OR = 3.75 (95% CI = 1.15-12. 22), respectively. Conclusion: C4268/C genotype may be a protective factor in lung adenocarcinoma patients and may decrease the risk of lung cancer in non-smokers and light-smorkers.

Influence of CYP2D6 polymorphisms on symptomatology and side effects of patients with schizophrenia in Malaysia

Background: Our objective was to investigate the association of CYP2D6 polymorphisms with symptoms and side-effects of patients with schizophrenia. Methods: The subjects were 156 patients with schizophrenia undergoing antipsychotic treatment at a psychiatric clinic. Patients with co-morbid diagnoses of substance abuse or mental retardation were excluded from the study. Psychopathology was evaluated using the Positive and Negative Symptoms Scale (PANSS). Extrapyramidal side-effects and akathisia were assessed with the Simpson Angus Scale (SAS) and the Barnes Akathisia Rating Scale (BARS), respectively. DNA was extracted from blood and subjected to PCR-genotyping. Results: We found that CYP2D6 polymorphisms were significantly associated with a subtotal negative PANSS score. In addition, CYP2D6 is not related to side-effects of antipsychotic therapy, or SAS and BARS scores. The results suggest that CYP2D6 polymorphisms may have implications in treatment response. Conclusions: Therefore, CYP2D6 may be a predictor for treatment outcomes of patients with schizophrenia. However, further investigation is required to confirm these findings in a larger sample.

Selection of an Antidepressant Based on the Genotypes of Cytochrome P450 Enzymes Genes in a Patient with Major Depressive Disorder / 대한정신약물학회지

We present a case of 34-year-old female patient with major depressive disorder who had decreased metabolic activity of CYP2D6. Low dosage regimen of mirtazapine & paroxetine led to unexpectedly severe adverse effects and noncompliance in this case with genotype CYP2D6 *1/*5. Antidepressant change to imipramine with consideration of the genotyping resulted with tolerable adverse effects and remission of depression. This case suggests the clinical usefulness of pharmacogenetic testing in individualized antidepressant treatments.

A Case Report of a Poor Metabolizer of CYP2D6 Presented with Unusual Responses to Nortriptyline Medication

We present a case with decreased metabolic activity of CYP2D6, a cytochrome P450 enzyme catalyzing the metabolism of nortriptyline (NT). Conventional dosage regimen led to toxic plasma concentration of NT and adverse effects such as dry mouth, constipation, and dizziness in this case with genotype CYP2D6*5/*10B. This case suggests the clinical usefulness of pharmacogenetic testing in individualized dosage adjustments of NT.

CYP2D6 gene G4268C single nucleotide polymorphism and genetic susceptibility to lung cancer / 第二军医大学学报

Objective:To evaluate the relation between the single nucleotide polymorphism of CYP2D6 gene G4268C and the genetic susceptibility to lung cancer. Methods: A case-control study was conducted among 118 lung cancer patients and 118 control subjects (matched for sex, age) to investigate the role of CYP2D6 gene G4268C polymorphism in lung cancer; PCR-RFLP was used to identify the genotypes of polymorphism. Logistic regression was used to analyze the relationship between polymorphism and genetic susceptibility to lung cancer. Results: The frequency of G4268→C mutation in case and control group were 69.49% and 75.00%, respectively. Non-C4268/C genotype (including G4268/G and G4268/C genotype) was correlated to the high risk of lung cancer, with OR adjusted by gender, age and smoking being 1.80 (95% CI=1.06-3.06), especially to lung adenocarcinoma (OR being 2.95 95% CI=1.39-6.23). After stratified analysis of smoking history and adjusting by gender and age, it was revealed that non-C4268/C genotype was associated with significantly increased risk of lung cancer in non-smokers and light-smokers group, with OR=2.12 (95% CI=1.03-4.36) and OR=3.75 (95% CI=1.15-12.22), respectively. Conclusion: C4268/C genotype may be a protective factor in lung adenocarcinoma patients and may decrease the risk of lung cancer in non-smokers and light-smorkers.