O Transtorno de Déficit de Atenção/Hiperatividade (TDAH) é comum em adultos e caracteriza-se por sintomas persistentes de desatenção, hiperatividade e impulsividade. Clinicamente, o TDAH é um fenótipo bastante heterogêneo e, frequentemente, encontra-se associado a diversos outros transtornos psiquiátricos. A contribuição genética é substancial no TDAH e diversos genes de pequeno efeito têm sido associados com o desenvolvimento do transtorno. O metilfenidato (MPH) representa o principal agente farmacológico usado no tratamento e seu mecanismo de ação parece envolver a potencialização da transmissão catecolaminérgica no córtex pré-frontal. Estudos farmacogenéticos têm investigado o papel de diversas variantes genéticas, principalmente em sistemas de neurotransmissão, na resposta ao tratamento com MPH. No entanto, esses estudos têm focado quase que exclusivamente no tratamento de crianças com TDAH. No presente trabalho foi investigada a associação entre 17 polimorfismos genéticos, em nove genes candidatos (DAT1, ADRA2A, 5-HTT, HTR1B, TPH2, DBH, DRD4, COMT e SNAP25), e a resposta ao tratamento com MPH. A amostra foi composta de 165 adultos com TDAH, diagnosticados de acordo com os critérios do DSM-IV. A gravidade dos sintomas dos pacientes foi avaliada antes e após um mês de uso de MPH através da aplicação das subescalas SNAP-IV e da escala CGI-S. Também avaliamos uma amostra de 136 dependentes de álcool e 237 controles, em um estudo de associação envolvendo o gene HTR1B. A resposta ao MPH foi analisada através de avaliações categórica e dimensional da redução nos sintomas após o uso de MPH. Foi observada uma redução significativa nos escores de gravidade total dos sintomas após o tratamento, sendo que 83% dos pacientes foram classificados como respondedores e 17% como não respondedores. Interpretamos a dificuldade de identificar variantes genéticas envolvidas na resposta ao tratamento como o reflexo da complexidade clínica e etiológica do TDAH. Exemplo disso é o fato de que o gene HTR1B, que apresenta resultados positivos para associação com o TDAH em meta-análises e em um estudo com crianças da nossa população, não se mostrou associado com o TDAH em adultos ou com a resposta ao MPH, mas sim com o alcoolismo nesse estudo. Novas investigações, em amostras maiores, serão necessárias para que seja alcançado maior sucesso nos estudos farmacogenéticos envolvendo o MPH ou outros fármacos no tratamento do TDAH. / Attention deficit/hyperactivity disorder (ADHD) has a high prevalence in adults and it is characterized by pervasive symptoms of inattention, hyperactivity and impulsivity. Clinically, ADHD is a very heterogeneous disorder frequently associated with other psychiatric conditions. The genetic contribution in ADHD is substantial and several genes of small effect have been associated with ADHD susceptibility. Methylphenidate (MPH) is the primary agent used in pharmacological intervention for ADHD. Its mechanism of action is believed to potentiate catecholamine transmission in the pre-frontal cortex. Pharmacogenetic studies have been investigating the role of genetic variants in the response to the treatment with MPH. However, previous studies have focused almost exclusively in the treatment of children with ADHD. In this study, we investigated the association between 17 polymorphisms, in 9 candidate genes (DAT1, ADRA2A, 5- HTT, HTR1B, TPH2, DBH, DRD4, COMT and SNAP25), and the response to MPH. The sample comprised 165 adults with ADHD diagnosed according to DSMIV criteria. We also evaluated a sample of 136 alcohol dependents and 237 control subjects, in an association study involving the HTR1B gene. The response to MPH was assessed by both categorical and dimensional approaches through the SNAP-IV sub-scales and the CGI-S scale, applied at the beginning and after the 30th day of treatment. We detected a significant reduction in SNAP-IV total scores during the follow-up period. According to the categorical definition of MPH response, 83% of the patients were classified as responders and 17% were classified as non-responders. Our results indicated that none of the investigated variants showed significant effects on the MPH response. We interpret the difficulty of identifying genetic variants involved in response to treatment as a reflection of the clinical and etiological complexity of ADHD. For example, we did not find association of the HTR1B gene with ADHD nor with treatment response to MPH in our adult sample, but it was in fact associated with alcohol dependence. However, this gene has previously shown positive results for association with children ADHD in meta-analysis and also in a study with children of the same population of the current work. More investigations with larger sample sizes will be need to achieve greater success in pharmacogenetic studies involving the MPH or other drugs used in the treatment of ADHD.

As HIV is now primarily a chronic condition, treatment is given life-long with changes as necessitated by alterations in tolerability and efficacy. Thus, personalized medicine may be useful in the prevention of unnecessary drug exposure and avoidable side effects. Three of the four currently available HIV integrase strand transfer inhibitors (INSTIs), raltegravir, elvitegravir, and dolutegravir, are widely utilized antiretrovirals in the USA and exhibit variations in outcomes among subjects. To interrogate differences among subjects receiving these drugs, we investigated the association of several single nucleotide polymorphisms (SNPs) with drug exposure, clinical outcomes, and subject-reported adverse events. HIV+ adults (≥18 years old) receiving an INSTI regimen were recruited (n=88). Subject genotypes were evaluated using an iPLEX PGx Panel. Genetic variations within our population, underwent multiple regression with covariates [age, sex, BMI, regimen duration, and baseline variables (as required) along with specific regimen in the comprehensive group] to detect significant (p=0.028) between abnormal dream occurrence and specific INSTI regimen with the raltegravir grouping presenting a higher frequency. This exploratory study also discovered several SNP-outcome associations when using INSTIs. Although these SNPs were found to have a role in predicting segments of adverse effect profiles, the clinical significance of these findings remains to be determined. Larger studies will be needed to confirm these exploratory findings with functional studies to understand pathogeneses. In conclusion, the associations found in this study strengthen the need for further assessment, within the HIV+ population, of factors contributing to unfavorable subject outcomes.

Pharmacogenetics is the study of genomic-guided individualized drug prescription that plays an important role in preventing the severe adverse effects of drugs, decreasing the time and cost of therapeutic choices, and directing healthcare professionals to choose medications that are effective and safe. It is noteworthy that this approach becomes highly beneficial in patients suffering from chronic diseases or disorders, since these conditions may require multiple and long term pharmacological therapies, as in children with autism spectrum disorder (ASD). However, public acceptance is a major challenge when implementation of pharmacogenetics merges into clinical practice. The purpose of this study is a) to investigate, among small cohort group of children with ASD, several genetic variants of enzymes that influence the metabolism of commonly prescribed drugs to treat ASD and b) to inspect the knowledge of, attitude towards and future expectations with regards to pharmacogenetics among parents of children with ASD. A group of 15 school-aged participants with ASD were recruited for the study. Approximately 5 ml of venous blood was drawn for each participant to analyze the genotype of enzymes implicated in drug metabolism via pharmacogenetics testing. Thereafter, the parents of these children attended a training session to help them gain a better understanding of the pharmacogenetics results depicted in the drug panel results. A pre-training and post-training survey was conducted to assess the knowledge of, attitude towards and future expectations of pharmacogenetics among the children’s parents.

Exposure to polycyclic aromatic hydrocarbons (PAHs) such as benzo(a)pyrene are important risk factors for cancer. Three UDP-glucuronosyltransferases, UGT1A9, UGT1A10, and UGT2B7, have been shown to play an important role in the phase II metabolism of carcinogenic metabolites of BaP. Because UGT1A9 and UGT2B7 are well-expressed in digestive tract tissues including liver and colon, it is possible that genetic variations in either enzyme may play an important role in colon cancer risk. However, UGT1A10 is extrahepatic and is expressed in the oral cavity and the larynx; therefore, genetic variations in this enzyme may play an important role in risk for orolaryngeal cancer. This study examined UGT1A9-, UGT1A10-, and UGT2B7-specific sequences for polymorphisms that play a role in cancer susceptibility. For the UGT1A9 gene, two missense polymorphisms at codons 167 (Val>Ala) and 183 (Cys>Gly) were identified. A previously-reported missense polymorphism was identified for the UGT2B7 gene. To assess the potential role of UGT1A10 variants as a risk factor for orolaryngeal cancer, PCR-RFLP was used to identify UGT1A10 genotypes in DNA specimens isolated from 115 African American newly-diagnosed orolaryngeal cancer cases and 115 non-cancer controls individually matched by age and race. A significantly decreased risk for orolaryngeal cancer was observed for subjects possessing one or more UGT1A10139Lys alleles as determined by crude analysis or after logistic regression analysis adjusting for age, sex, smoking and alcohol consumption. These results strongly suggest that the UGT1A10139Lys polymorphism may play an important protective role in risk for orolaryngeal cancer. To determine whether the change in amino acid sequence at codon 183 results in aberrant UGT1A9 enzyme activity, functional characterization of the wild-type- and variant-encoded UGT1A9 isoforms was performed in vitro. Cell homogenates were prepared from UGT1A9-transfected HK293 cells and glucuronidation assays were performed against various carcinogens/carcinogen metabolites. A significant (p<0.001) 3- to 4-fold decrease in enzyme activity, determined by HPLC analysis, was observed for the UGT1A9183Gly variant as compared to its wild-type counterpart for all substrates analyzed. These results demonstrate that the UGT1A9 (Cys183Gly) polymorphism significantly alters UGT1A9 function and could potentially play an important role as risk modifier for digestive tract cancers.

<p>Hypertension is common and constitutes an increased risk of morbidity and mortality of cardiovascular disease. Antihypertensive treatment will reduce this risk; the individual patient's response to treatment, however, is difficult to predict.</p><p>Patients with hypertension and left ventricular hypertrophy were randomized to monotherapy with either the angiotensin II type 1 receptor antagonist irbesartan or the beta-adrenoreceptor blocker atenolol, and followed for three months. The aim was to determine whether gene polymorphisms in the renin-angiotensin-aldosterone system were related to the response to treatment.</p><p>The ACE II genotype was associated with the most pronounced diastolic blood pressure response, while the aldosterone synthase (CYP11B2) -344 TT genotype showed the greatest systolic blood pressure response. The angiotensinogen 174 TM genotype showed the most pronounced regression in left ventricular mass, independent of the change in blood pressure. These associations were exhibited only in response to treatment with the angiotensin II type 1 receptor antagonist irbesartan.</p><p>In a sample of apparently healthy subjects, those with both the D allele and the angiotensinogen 174 TM variant in combination showed a decreased endothelium-dependent vasodilation.</p><p>These results suggest that the response to antihypertensive treatment is associated with polymorphisms in the genes reflective of the pathophysiological pathway the drug targets. The present study is an encouragement for future investigation, such as large scale studies of multiple polymorphisms and combinations thereof in an attempt to identify a panel of genotypes that can be used as a predictor of an individual patient's response to anithypertensive treatment.</p>

Hypertension is common and constitutes an increased risk of morbidity and mortality of cardiovascular disease. Antihypertensive treatment will reduce this risk; the individual patient's response to treatment, however, is difficult to predict. Patients with hypertension and left ventricular hypertrophy were randomized to monotherapy with either the angiotensin II type 1 receptor antagonist irbesartan or the beta-adrenoreceptor blocker atenolol, and followed for three months. The aim was to determine whether gene polymorphisms in the renin-angiotensin-aldosterone system were related to the response to treatment. The ACE II genotype was associated with the most pronounced diastolic blood pressure response, while the aldosterone synthase (CYP11B2) -344 TT genotype showed the greatest systolic blood pressure response. The angiotensinogen 174 TM genotype showed the most pronounced regression in left ventricular mass, independent of the change in blood pressure. These associations were exhibited only in response to treatment with the angiotensin II type 1 receptor antagonist irbesartan. In a sample of apparently healthy subjects, those with both the D allele and the angiotensinogen 174 TM variant in combination showed a decreased endothelium-dependent vasodilation. These results suggest that the response to antihypertensive treatment is associated with polymorphisms in the genes reflective of the pathophysiological pathway the drug targets. The present study is an encouragement for future investigation, such as large scale studies of multiple polymorphisms and combinations thereof in an attempt to identify a panel of genotypes that can be used as a predictor of an individual patient's response to anithypertensive treatment.

Background and objectives: Several new psychoactive drugs for the treatment of psychiatric disorders have been introduced onto the market since the late 1980s. Basic aspects of pharmacodynamics and pharmacokinetics (PK) are investigated before approval for general prescription. Thus, a limited number of subjects are exposed to the drug before it is marketed and only sparse measurements of drug concentration are performed during phases II and III of drug development. The objective of this thesis was to provide further descriptive PK and linked patients data in naturalistic clinical settings. The PK of psychoactive drugs was also studied in the elderly and the young, major risk groups that are exposed in normal everyday clinical practice but that are underrepresented in the phases of drug development. The PK-data were to be assessed by samples sent to the Therapeutic Drug Monitoring (TDM) laboratory service. In a subset of individuals, the genotypes of the cytochrome P450 (CYP) enzymes were described. Results: Serum concentration of the parent compound and its metabolites was provided from TDM-data on antidepressant escitalopram (Paper I) and antipsychotic ziprasidone (Paper II). A large interindividual PK variability was found. The daily dose of the drug was higher than the defined daily dose (DDD) for both escitalopram and ziprasidone (median dose 20 mg and 120 mg, respectively). The median number of drugs per patient, apart from the studied drug, was 4 and 3, respectively (range 1-18). If repeated eligible TDM-data were available, change in treatment strategies could be seen between the first and second sample for the patient, and the metabolite/parent compound (M/P) ratio had lower intraindividual than interindividual variation in the escitalopram study but opposite results were found in the ziprasidone study. The prescription of antidepressant drugs (ADs) in the nursing homes studied was 38 % (Paper III). The concentration of the ADs was higher, or much higher, than could be expected from the dose administered in 73 %. The majority of the elderly people were treated with citalopram. No clear time schedule for how long the drug treatment should continue was found in the patients’ current medical record. The median number of drugs per patient apart from the AD was 11 (range 4-19), no monotherapy was found in these patients. The genetically impaired metabolic activity of CYP enzymes correlated to higher drug concentration as expected, in patients medicated with an AD that is substrate for the CYP enzyme genotype. The concentrations of ADs were as expected from the dose administered in 63 % of the children/adolescents evaluated (Paper IV). The majority of TDM samples requested sertraline. PK outcome of sertraline was similar to the results in adult populations. Monotherapy was documented in 49 % (median number of drugs apart from AD was 1 per patient, range 1-7). Changes in treatment strategies were also shown, if repeated TDM-samples were available. The median variation of the M/P ratio for sertraline between the first and the last samples within the same patient was 20 % (the interindividual variation was 37 %). The poor metabolizers (PM) for CYP2D6 medicated with a CYP2D6 substrate had a lower dose than did non-PM for the same drug. Conclusion: These studies provide reference data for the evaluation of the therapeutic response, i.e. a reference range of what is to be expected in a normal clinical setting, as well as the toxicological information concerning the psychoactive drugs studied. When available, the M/P ratio between two patients’ samples may assess patient compliance, as well as drug-drug interactions. Thus, the use of TDM can be beneficial for individual dose optimisation and drug safety, above all in the studied populations, elderly people and children/adolescents, when the selection of doses requires a consideration of PK parameters. TDM may be a tool for research, increasing knowledge of the psychoactive drug in TDM service, as well as toxicology. A more frequent clinical use of TDM and pharmacogenetic testing in clinical practice would contribute to a better quality when treating with psychoactive drugs.

The impact of CYP2A6 and CYP2B6 genetic variation on nicotine metabolism, tobacco use behaviours, and nicotine biomarkers was investigated in a group of Alaska Natives (n = 400). CYP2A6 and CYP2B6 allele frequencies were unique and associations of CYP2A6 genotype and CYP2A6 activity (plasma and urine trans 3’-hydroxycotinine/cotinine (3HC/COT) ratios) were robust. Notably, this population possessed a more rapid rate of CYP2A6 activity (higher plasma 3HC/COT) when compared to CYP2A6 wild-type individuals in other ethnic groups (ANOVA P < 0.001). Also demonstrated was a significant difference in urine total nicotine equivalents by CYP2A6 activity median split (t-test P < 0.01), the first evidence of nicotine titration by CYP2A6 activity within a light smoking population. Overall, this population possessed a distinctive pattern of CYP2A6 and CYP2B6 variant frequencies and a faster rate of nicotine metabolism, which may in part explain higher levels of tobacco use prevalence and tobacco-related disease risk.

The impact of CYP2A6 and CYP2B6 genetic variation on nicotine metabolism, tobacco use behaviours, and nicotine biomarkers was investigated in a group of Alaska Natives (n = 400). CYP2A6 and CYP2B6 allele frequencies were unique and associations of CYP2A6 genotype and CYP2A6 activity (plasma and urine trans 3’-hydroxycotinine/cotinine (3HC/COT) ratios) were robust. Notably, this population possessed a more rapid rate of CYP2A6 activity (higher plasma 3HC/COT) when compared to CYP2A6 wild-type individuals in other ethnic groups (ANOVA P < 0.001). Also demonstrated was a significant difference in urine total nicotine equivalents by CYP2A6 activity median split (t-test P < 0.01), the first evidence of nicotine titration by CYP2A6 activity within a light smoking population. Overall, this population possessed a distinctive pattern of CYP2A6 and CYP2B6 variant frequencies and a faster rate of nicotine metabolism, which may in part explain higher levels of tobacco use prevalence and tobacco-related disease risk.

Thiopurine methyltransferase (TPMT) risk alleles (mainly *2,*3B, *3C and *3A) are the major determinants of interindividual differences in the severe toxicity or efficacy of 6-mercaptopurine (6MP) during the treatment of childhood acute lymphoblastic leukemia (ALL). The frequencies of these risk alleles, known to functionally impair TPMT activity, were investigated among 167children with ALL and 206 healthy adult controls in Turkish population by using allele specific PCR and PCRRFLP methods. TPMT*3A and TPMT*3C were the only deficiency alleles detected in Turkish population with an allele frequency of 0.5% for both. The total frequency of mutant TPMT alleles in Turkish population (1.0%) was found to be significantly lower than those of other Caucasian populations (5.3-7.0%), but it was found to be very similar to Kazak population (1.2%) which is also Caucasian in ethnic origin. v In the patient group, two individuals were found to be heterozygote for *3C and *3A allele. One individual was homozygous mutant (*3B/*3C). In this study, the clinical histories of the patients with TPMT defects were examined retrospectively from hospital records. The patients with heterozygous or homozygous mutant genotypes had systematically developed severe neutropenia, infection and some other specific conditions (like lesions around mouth, oral herpes and high fever) when they were administered with 6MP during the therapy. This study provides the first data on the frequency of common TPMT risk alleles in the Turkish population, based on analysis of pediatric patients with ALL. The results would contribute valuable information to the public health, as more clinicians and patients become aware of the importance of TPMT polymorphisms, less patients will suffer from 6MP related adverse effects. In addition, in this study two genes EPHX1-microsomal epoxide hydrolase (exon 3 and exon 4 polymorphisms) and SULT1A1*2 variant &ndash / sulfotransferase 1A1, either alone or in combination were investigated as risk modifiers in the development of childhood acute lymphoblastic leukemia due to their dual role (activation/detoxification) in the metabolism of various carcinogens. Also interactions of these polymorphisms with non-genetic risk factors (parental smoking exposure and parental age at conception) were investigated. The conclusion inferred from results was that only genetically reduced EPHX1 activity (homozygous mutant genotype for EPHX1 exon 3 polymorphism and some specific genotype combinations with exon 4 polymorphism) was found to be significantly associated with the risk of childhood ALL.