A 40-bp VNTR polymorphism in the 3'-untranslated region of DAT1/SLC6A3 is associated with ADHD but not with alcoholism.

BACKGROUND: ADHD and alcoholism are psychiatric diseases with pathophysiology related to dopamine system. DAT1 belongs to the SLC6 family of transporters and is involved in the regulation of extracellular dopamine levels. A 40 bp variable number tandem repeat (VNTR) polymorphism in the 3'-untranslated region of DAT1/SLC6A3 gene was previously reported to be associated with various phenotypes involving disturbed regulation of dopaminergic neurotransmission. METHODS: A total of 1312 subjects were included and genotyped for 40 bp VNTR polymorphism of DAT1/SLC6A3 gene in this study (441 alcoholics, 400 non-alcoholic controls, 218 ADHD children and 253 non ADHD children). Using miRBase software, we have performed a computer analysis of VNTR part of DAT1 gene for presence of miRNA binding sites. RESULTS: We have found significant relationships between ADHD and the 40 bp VNTR polymorphisms of DAT1/SLC6A3 gene (P < 0.01). The 9/9 genotype appeared to reduce the risk of ADHD about 0.4-fold (p < 0.04). We also noted an occurrence of rare genotypes in ADHD (frequency different from controls at p < 0.01). No association between alcoholism and genotype frequencies of 40 bp VNTR polymorphism of DAT1/SLC6A3 gene has been detected. CONCLUSIONS: We have found an association between 40 bp VNTR polymorphism of DAT1/SLC6A3 gene and ADHD in the Czech population; in a broad agreement with studies in other population samples. Furthermore, we detected rare genotypes 8/10, 7/10 and 10/11 present in ADHD boys only and identified miRNAs that should be looked at as potential novel targets in the research on ADHD.

Spinocerebellar ataxias type 8, 12, and 17 and dentatorubro-pallidoluysian atrophy in Czech ataxic patients.

Spinocerebellar ataxias (SCAs) are a heterogeneous group of neurodegenerative disorders currently associated with 27 genes. The most frequent types are caused by expansions in coding CAG repeats. The frequency of SCA subtypes varies among populations. We examined the occurrence of rare SCAs, SCA8, SCA12, SCA17 and dentatorubro-pallidoluysian atrophy (DRPLA), in the Czech population from where the data were missing. We analyzed causal gene expansions in 515 familial and sporadic ataxic patients negatively tested for SCA1-3 and SCA6-7. Pathogenic SCA8 and SCA17 expansions were identified in eight and five patients, respectively. Tay-Sachs disease was later diagnosed in one patient with an SCA8 expansion and the diagnosis of multiple sclerosis (MS) was suspected in two other patients with SCA8 expansions. These findings are probably coincidental, although the participation of SCA8 expansions in the susceptibility to MS and disease progression cannot be fully excluded. None of the patients had pathogenic SCA12 or DRPLA expansions. However, three patients had intermediate SCA12 alleles out of the normal range with 36 and 43 CAGs. Amyotrophic lateral sclerosis (ALS) was probable in the patient with 43 CAGs. This coincidence is remarkable, especially in the context with the recently identified predisposing role of longer SCA2 alleles in ALS. Five families with SCA17 represent a significant portion of ataxic patients and this should be reflected in the diagnostics of SCAs in the Czech population. SCA8 expansions must be considered after careful clinical evaluation.

Rapid testing of clopidogrel resistance by genotyping of CYP2C19 and CYP2C9 polymorphisms using denaturing on-chip capillary electrophoresis.

Antiplatelet therapy is a cornerstone of cardiovascular treatment in patients with coronary artery disease and after myocardial infarction. Clopidogrel has become a popular antiplatelet agent due to its fast action and low frequency of adverse effects. Kinetics of clopidogrel metabolism is driven by enzymatic activity of the Cytochrome P450 system. Genotyping of CYP2C19 and CYP2C9 polymorphisms allows to identify slow metabolizers showing resistance to clopidogrel therapy. Today, a number of PCR-based techniques for single nucleotide polymorphism genotyping directed at clopidogrel resistance polymorphisms are in use. Here, we describe a new alternative genotyping approach combining the separation power of denaturing capillary electrophoresis with the analysis speed and ease of use of Bioanalyzer chipCE platform. Using an upgraded heater control, we present an optimization for allele separation of CYP2C19 I331V, CYP2C9 R144C, and CYP2C9 I359L polymorphisms employing run temperatures of up to 55°C. We demonstrate rapid and accessible approach to reproducible clopidogrel resistance with feasibility and low cost.

Clinical significance of hypermethylation status in NSCLC: evaluation of a 30-gene panel in patients with advanced disease.

BACKGROUND: DNA methylation is one of major factors in cancer progression. We observed multiple genes involved in cancer-related signaling and focused on patients with advanced non-small cell lung cancer (NSCLC) and evaluated methylation in relation to various clinical parameters. PATIENTS AND METHODS: Thirty genes were examined in 121 NSCLC patients using the methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) method. Correlations to gender, smoking status, tumor subtype, disease stage and EGFR/KRAS mutation status were performed by chi-square test. RESULTS: 90% of tumors exhibited methylation of at least one gene. Most frequently methylated were cadherin-13 (CDH13), Ras associated domain-containing protein (RASSF1A), Wilms' tumor protein (WT1), adenomatous polyposis coli protein (APC), paired box protein Pax-5 (PAX5), estrogen receptor (ESR1), an inhibitor of cyclin-dependent kinase p15 (CDKN2B), paired box protein Pax-6 (PAX6), transcription factor GATA-5 (GATA5) and cell adhesion molecule 4 (IGSF4). Overall methylation (any gene) was increased in adenocarcinomas (p=0.0329), unrelated to gender or disease stage. Several genes exhibited variable methylation with gender (CDH13, p<0.001; GATA5, p=0.02; PAX6, p=0.01 and ESR1, p=0.03), smoking (CDH13, p=0.002), or epidermal growth factor receptor (EGFR) mutation status [Von Hippel-Lindau disease tumor supresor (VHL), p=0.001; CDKN2B, p=0.02; CDH13, p=0.02; APC, p=0.04 and ESR1, p=0.04]. CONCLUSION: Differences in gene methylation associated with gender, smoking and EGFR mutation suggest potential for prediction in relation to management of tyrosine kinase inhibitor therapy.

The association between TaqI A polymorphism of ANKK1 (DRD2) gene and ADHD in the Czech boys aged between 6 and 13 years.

OBJECTIVE: The purpose of this study was the correlation of the combined type of ADHD in children and Taq IA polymorphism DRD2 gene. We hypothesized a positive correlation of DRD2 polymorphisms in the combined type of ADHD patients without co-morbidity. PATIENTS AND METHODS: Our research sample included 586 unrelated boys of the Czech origin aged between 6 and 13 years. The ADHD group consisted of 269 boys and the control group consisted of 317 boys. PCR detection of the DRD2 polymorphism was carried out by using primers, described by Grandy (Grandy et al. 1989). RESULTS: The comparison of genotype frequencies showed statistically highly significant difference between the studied groups (p<0.0001). A statistically significant difference was also found when the allelic frequencies between the two groups were compared (p<0.0001), with the A1 allele having a 4.359 fold higher risk of ADHD (Risk Ratio=4.359, 95% CI of RR=3.5753 to 5.3144, Odds Ratio= 7.7824; 95% CI of OR=10.315 to 13.6719). CONCLUSIONS: Our results presented a highly positive correlation between the combined type of ADHD without co-morbidity and ANKK l (DRD2) polymorphism .

Dopamine beta hydroxylase (DBH) plasma activity in childhood mental disorders.

BACKGROUND: Developmental study of dopaminergic and noradrenergic systems in child psychiatric disorders are rare. DBH activity is one of noradrenergic biochemical marker that is correlate in psychiatry to clinical and genetic data. OBJECTIVES: The main aim of the present study was to measure DBH activity at the onset of acute schizophrenia and depressive disorder in children and adolescents without pharmacological treatment and to compare these values with DBH activity in healthy controls. The authors also investigated untreated ADHD children. METHODS: We examined 42 control healthy children, 15 children non-treated with acute schizophrenia, 15 non-treated children with acute depressive disorders and 30 non-treated ADHD children, all in age 7-14. Plasma DBH level was provided by Nagatsu (1972; 1974). Depressed children were reexamined after clinical remission. RESULTS: DBH activity is statistically significantly decreased in non-treated depressive disorder and ADHD in children and adolescents. DBH activity is normalised during antidepressant therapy in child depression. Child schizophrenia patients present with normal DBH activity. CONCLUSION: These results are similar to the results that have been observed in adult patients with schizophrenia and depression and in previous studies of DBH activity in children with ADHD. These results also indicate hypoactivity of the noradrenergic system in children with ADHD and depression.

Some ADHD polymorphisms (in genes DAT1, DRD2, DRD3, DBH, 5-HTT) in case-control study of 100 subjects 6-10 age.

BACKGROUND: Pharmacological approach is the most effective way of treatment of ADHD and its early application prevents from the progress of secondary disorders. The study on present neurotransmitter systems in pathology of ADHD can be helpful in selecting appropriate drug, since there are used various substances with different mechanisms of functioning in treatment of the hyperkinetic syndrome. METHOD: Within our study there were selected the genes of dopaminergic (DRD2, DRD3, DAT1), noradrenergic (DBH) and serotoninergic (5-HTT) systems. With the use of molecular-genetic methods based on association strategy "case-control" there were analysed genes including 11 polymorphisms. The presence of risk alleles was examined in comparison of the sample of 100 ADHD children to a control group of another 100 subjects, who were checked by child psychiatrists and examined with the Conners test in order to exclude eventual cases with ADHD symptoms. RESULTS: Our research suggests the association of some genes with ADHD. It could be concluded: 1) the risk of ADHD is significantly increased in the presence of one risk allele in genes DRD2 (O.R.=7,5), 5-HTT (O.R.=2,7) and DAT1 (O.R.=1,6). 2) The risk of ADHD is significantly increased at homozygotes for risk alleles in genes DRD2 (O.R.=54,8), 5-HTT (O.R.=6,7) and DAT1 (O.R.=6,6). For polymorphisms G444A and C1603T in DBH, which were detected by univariant analysis, haplotype analysis was performed and resulted in conclusion that: 3) the risk of ADHD is significantly increased in the presence of allele DBH +444A as well as in the presence of allele DBH +1603T (O.R.=15).

Polymorphisms and low plasma activity of dopamine-beta-hydroxylase in ADHD children.

Attention-deficit Hyperactivity disorder (ADHD) is a multifactorial disorder clinically characterized by inattentiveness, impulsivity and hyperactivity. The occurrence of this disorder is between 3 and 6% of the children population, with boys predominating over girls at a ratio of 3:1 or more. The research of some candidate genes (DRD4, DAT, DRD5, DBH, 5HTT, HTR1B and SNAP25) brought consistent results confirming the heredity of ADHD syndromes. Dopamine-beta-hydroxylase (DBH) is an enzyme responsible for the conversion of dopamine into noradrenaline. Alteration of the dopamine/noradrenaline levels can result in hyperactivity. The DBH protein is released in response to stimulation. DBH activity, derived largely from sympathetic nerves, can be measured in human plasma. Patients with ADHD showed decreased activities of DBH in serum and urine. Low DBH levels correlate indirectly with the seriousness of the hyperkinetic syndrome in children [19,20]. In the DBH gene, the G444A, G910T, C1603T, C1912T, C-1021T, 5 -ins/del and TaqI polymorphisms occur frequently and may affect the function of gene products or modify gene expression and thus influence the progression of ADHD. This article reviews the DBH itself and polymorphisms in the DBH gene that influence the DBH activity in the serum and the CSF level of DBH. All those are evaluated in connection with ADHD.