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Lack of association of polymorphisms in six candidate genes in colombian adhd patients.

ABSTRACT: BACKGROUND:Attention Deficit and Hyperactivity Disorder (ADHD) is a common childhood neuropsychiatric condition. The disorder has a multifactorial background, with heritability estimates of around 76%, suggesting an important role of genetic factors. Candidate genes include those related to dopaminergic (e.g. DRD4, DRD5, SLC6A3 and DBH)and serotoninergic (e.g.HTR1B and SLC6A4) pathways. PURPOSE:To explore the association of common polymorphisms in six genes (DRD4, DRD5, SLC6A3, DBH, HTR1B and SLC6A4) and the susceptibility to ADHD in a Colombian sample population. METHODS:trios and 152 healthy controls were recruited. Genotyping of the six polymorphisms was performed using described PCR-based protocols. A TDT analysis was used to test if there was preferential allelic transmission for any of the six polymorphisms. Additionally, a case-control analysis was performed to test for association of the serotoninergic (HTR1B and SLC6A4) polymorphisms with ADHD. RESULTS:Through the TDT analysis there was no preferential allelic transmission for any of the studied variants. Case-control analysis did not show association. CONCLUSION:This is the first study in Latin America to describe six polymorphisms in a group of patients with ADHD. There was no evidence of association for any of the studied polymorphic variants in this Colombian ADHD sample. Further research, with larger sample sizes and study of endophenotypes, is needed in this population to confirm and extend the results.

SUBMITTER: Fonseca DJ

PROVIDER: S-EPMC4627201 | biostudies-literature | 2015 Oct

REPOSITORIES: biostudies-literature

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Lack of association of polymorphisms in six candidate genes in colombian adhd patients.

Fonseca Dora J DJ Mateus Heidi E HE Gálvez Jubby M JM Forero Diego A DA Talero-Gutierrez Claudia C Velez-van-Meerbeke Alberto A

Annals of neurosciences 20151001 4

<h4>Background</h4>Attention Deficit and Hyperactivity Disorder (ADHD) is a common childhood neuropsychiatric condition. The disorder has a multifactorial background, with heritability estimates of around 76%, suggesting an important role of genetic factors. Candidate genes include those related to dopaminergic (e.g. DRD4, DRD5, SLC6A3 and DBH)and serotoninergic (e.g.HTR1B and SLC6A4) pathways.<h4>Purpose</h4>To explore the association of common polymorphisms in six genes (DRD4, DRD5, SLC6A3, DB ...[more]

PMID: 26526368

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Project description:IntroductionSchizophrenia is a chronic heterogenic neurodevelopment disorder. Many genes interfere in the development of SCZ. All four genes, NrCAM, PRODH, ANK3, and ANKK1, which were evaluated in this study, were previously reported to be associated with Schizophrenia. The NrCAM contributes to creating cognitive deficiencies through the CAM's signaling pathway. PRODH plays a vital role in creating SCZ negative symptoms through the signaling pathway of glutamatergic and NMDA receptors. ANK3 affects ion channel and molecular adhesion in Ranvier and initial segments of axons, leading to mental retardation, sleep disorder, and SCZ. ANKK1 encodes a protein kinase and was reported to be associated with alcohol addiction, Attention Deficit Hyperactivity Disorder (ADHD), and SCZ.MethodsThe subjects were selected from Schizophrenic patients referring to the Psychiatric Ward of Imam-Hussein Hospital and Schizophrenic Patients Support Institution (AHEBBA). 95 (30 Schizoaffective patients, 57 Paranoid patients, and 8 disorganized) patients were recruited as the subjects in the present case-control association study. 120 healthy subjects were recruited from the Tehran Medical Genetics Laboratory staff and a group of students from the Islamic Azad University of Science and Research in Tehran. The genotypes were determined with molecular genotyping techniques of PCR-RFLP, ARMS-PCR, and Cycle sequencing. Results were analyzed by the Chi-Square test using SPSS V. 24 and R, SNP STATE Package to investigate significant differences between cases and controls.ResultsThe incidence of schizophrenia was 68% and 32% among men and women, respectively. The evaluation of the allelic association between schizophrenia and all the candidate SNPs showed a significant association between NrCAM's SNP rs10235968 and SCZ (P=0.001). Haplotype T, T, C in rs10235968, rs6967368, rs3763463, respectively, within the NrCAM gene, showed significant association with schizophrenia disorder (P=0.0001).ConclusionNo association was found between other candidate SNPs and SCZ among the subjects.

Project description:BackgroundWe reviewed systematically the results of genetic studies investigating associations between putative susceptibility genes for attention-deficit hyperactivity disorder (ADHD) and neuropsychological traits relevant for this disorder.MethodsWe identified papers for review through the PubMed database.ResultsTwenty-nine studies examined 10 genes (DRD4, DAT1, COMT, DBH, MAOA, DRD5, ADRA2A, GRIN2A, BDNF and TPH2) in relation to neuropsychological traits relevant for ADHD. For DRD4, the continuous performance test (CPT) and derived tasks were the most used tests. Association of high reaction time variability with the 7-repeat allele absence appears to be the most consistent result and seems to be specific to ADHD. Speed of processing, set-shifting and cognitive impulsiveness were less frequently investigated but seem to be altered in the 7-repeat allele carriers. No effect of genotype was found on response inhibition (the stop and go/no-go tasks). For DAT1, 4 studies provide conflicting results in relation to omission and commission errors from CPT and derived tasks. High reaction time variability seems to be the most replicated cognitive marker associated with the 10-repeat homozygosity. The other genes have attracted fewer studies, and the reported findings need to be replicated.LimitationsAlthough we aimed to perform a formal meta-analysis, this was not possible because the number of studies using the same neurocognitive endophenotypes was limited. We referred only minimally to the various theoretical frameworks in this field of research; more detail would have been beyond the scope of our systematic review. Finally, sample sizes in most of the studies we reviewed were small. Thus, some negative findings could be attributed to a lack of statistical power, and positive results should be considered preliminary until they are replicated in extended samples.ConclusionSeveral methodological issues, including measurement errors, developmental changes in cognitive abilities, sex, psychostimulant effects and presence of comorbid conditions, represent confounding factors and may explain conflicting results.

Project description:OBJECTIVE:The purpose of this study was to investigate the genetic effects of six keratin (KRT) genes on the wool traits of 418 Chinese Merino (Xinjiang type) (CMXT) individuals. METHODS:To explore the effects and association of six KRT genes on sheep wool traits, The polymerase chain reaction-based single-strand conformation polymorphism (PCR-SSCP), DNA sequencing, and the gene pyramiding effect methods were used. RESULTS:We report 20 mutation sites (single-nucleotide polymorphisms) within the six KRT genes, in which twelve induced silent mutations; five induced missense mutations and resulted in Ile?Thr, Glu?Asp, Gly?Ala, Ala?Ser, Se?His; two were nonsense mutations and one was a same-sense mutation. Association analysis showed that two genotypes of the KRT31 gene were significantly associated with fiber diameter (p<0.05); three genotypes of the KRT36 gene were significantly associated with wool fineness score and fiber diameter (p<0.05), three genotypes of the KRT38 gene were significantly associated with the number of crimps (p< 0.05); and three genotypes of the KRT85 gene were significantly associated with wool crimps score, body size, and fiber diameter (p<0.05). Analysis of the gene pyramiding effect between the different genotypes of the gene loci KRT36, KRT38, and KRT85, each genotype in a gene locus was combined with all the genotypes of another two gene loci and formed the different three loci combinations, indicated a total of 26 types of possible combined genotypes in the analyzed population. Compared with the other combined genotypes, the combinations CC-GG-II, CC-HH-IJ, CC-HH-JJ, DD-HH-JJ, CC-GH-IJ, and CC-GH-JJ at gene loci KRT36, KRT38, and KRT85, respectively, had a greater effect on wool traits (p<0.05). CONCLUSION:Our results indicate that the mutation loci of KRT31, KRT36, KRT38, and KRT85 genes, as well as the combinations at gene loci KRT36, KRT38, and KRT85 in CMXT have significant effects on wool traits, suggesting that these genes are important candidate genes for wool traits, which will contribute to sheep breeding and provide a molecular basis for improved wool quality in sheep.

Project description:PurposeTo evaluate genes involved in homocysteine metabolism as secondary risk factors for pseudoexfoliation syndrome (PXFS) and the associated glaucoma (PXFG).MethodsOne hundred eighty-six unrelated patients with PXFS, including 140 patients with PXFG and 127 unrelated control subjects were recruited from the Massachusetts Eye and Ear Infirmary. All the patients and controls were Caucasian of European ancestry. Seventeen tag SNPs from 5 genes (methylenetetrahydrofolate reductase [MTHFR], methionine synthase [MTR], methionine synthase reductase [MTRR], methylenetetrahydrofolate dehydrogenase [MTHFD1], and cystathionine beta-synthase [CBS]) were genotyped. Single-SNP association was analyzed using Fisher's exact test (unconditional) or logistic regression after conditioning on the effects of age and three LOXL1 SNPs (rs1048661, rs3825942, and rs2165241). Interaction analysis was performed between the homocysteine and LOXL1 SNPs using logistic regression. Haplotype analysis and the set-based test were used to test for association of individual genes. Multiple comparisons were corrected using the Bonferroni method.ResultsOne SNP (rs8006686) in MTHFD1 showed a nominally significant association with PXFG (p=0.015, OR=2.23). None of the seventeen SNPs tested were significantly associated with PXFS or PXFG after correcting for multiple comparisons (Bonferroni corrected p>0.25). After controlling for the effects of age and three associated LOXL1 SNPs, none of the seventeen tested SNPs were associated with PXFS (p>0.12). No significant interaction effects on PXFS were identified between the homocysteine and LOXL1 SNPs (p>0.06). Haplotype analysis and the set-based test did not find significant association of individual genes with PXFS (p>0.23 and 0.20, respectively).ConclusionsFive genes that are critical components of the homocysteine metabolism pathway were evaluated as secondary factors for PXFS and PXFG. Our results suggest that these genes are not significant risk factors for the development of these conditions.

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Lack of association of polymorphisms in six candidate genes in colombian adhd patients.

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Lack of association of polymorphisms in six candidate genes in colombian adhd patients.

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