Genetic polymorphism of CYP2C19 and subcortical variability in the human adult brain.
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ABSTRACT:
SUBMITTER: Stingl JC
PROVIDER: S-EPMC8426391 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:The highly complex structure of the human brain is strongly shaped by genetic influences. Subcortical brain regions form circuits with cortical areas to coordinate movement, learning, memory and motivation, and altered circuits can lead to abnormal behaviour and disease. To investigate how common genetic variants affect the structure of these brain regions, here we conduct genome-wide association studies of the volumes of seven subcortical regions and the intracranial volume derived from magnetic resonance images of 30,717 individuals from 50 cohorts. We identify five novel genetic variants influencing the volumes of the putamen and caudate nucleus. We also find stronger evidence for three loci with previously established influences on hippocampal volume and intracranial volume. These variants show specific volumetric effects on brain structures rather than global effects across structures. The strongest effects were found for the putamen, where a novel intergenic locus with replicable influence on volume (rs945270; P = 1.08 × 10(-33); 0.52% variance explained) showed evidence of altering the expression of the KTN1 gene in both brain and blood tissue. Variants influencing putamen volume clustered near developmental genes that regulate apoptosis, axon guidance and vesicle transport. Identification of these genetic variants provides insight into the causes of variability in human brain development, and may help to determine mechanisms of neuropsychiatric dysfunction.
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Project description:CYP2C19 polymorphism is associated with pretreatment drug response prediction, metabolism, and disposition. Pakistan consists of a population comprising of various ethnic groups residing in different regions of the country each claiming diverse ethnic origins. The identification of CYP450 genotypic composition of these populations is therefore necessary to avoid adverse drug reactions in these individuals. The main objective of the study was to investigate the prevalence of CYP2C19*2 and CYP2C19*17 alleles in these ethnic groups. The study was conducted on one thousand and twenty-eight (n = 1028) healthy volunteers from nine ethnic groups of Pakistan namely Brusho (n = 28), Hazara (n = 102), Kalash (n = 64), Pathan (n = 170), Punjabi (n = 218), Saraiki (n = 59), Brahui (n = 118), Parsi (n = 90), and Sindhi (n = 179). DNA was extracted from leukocytes and analyzed by allele specific amplification polymerase chain reaction (ASA-PCR). Multi allelic polymorphism of CYP2C19 led to four distinct phenotypes identified as extensive metabolizer (EM), poor metabolizer (PM), intermediate metabolizer (IM), and ultra-rapid metabolizer (UM). Over all, the percentage of predicted poor metabolizer allele was 29.0% compared to UM allele (23.70%). Among the studied groups, Saraiki and Brahui showed highest percentage of PM allele (40%, 36%) whereas Parsi and Hazara had highest percentage of UM allele (37% and 30% respectively). In conclusion, the high allele frequency of PM (CYP2C19*2 and *17) in Pakistani population led to the recommendation of a pre-treatment test to monitor drug response and dosage (personalized medicine) to avoid post-treatment adverse drug reactions.
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Project description:Genome-wide association screens aim to identify common genetic variants contributing to the phenotypic variability of complex traits, such as human height or brain morphology. The identified genetic variants are mostly within noncoding genomic regions and the biology of the genotype-phenotype association typically remains unclear. In this article, we propose a complementary targeted strategy to reveal the genetic underpinnings of variability in subcortical brain volumes, by specifically selecting genomic loci that are experimentally validated forebrain enhancers, active in early embryonic development. We hypothesized that genetic variation within these enhancers may affect the development and ultimately the structure of subcortical brain regions in adults. We tested whether variants in forebrain enhancer regions showed an overall enrichment of association with volumetric variation in subcortical structures of >13,000 healthy adults. We observed significant enrichment of genomic loci that affect the volume of the hippocampus within forebrain enhancers (empirical P = 0.0015), a finding which robustly passed the adjusted threshold for testing of multiple brain phenotypes (cutoff of P < 0.0083 at an alpha of 0.05). In analyses of individual single nucleotide polymorphisms (SNPs), we identified an association upstream of the ID2 gene with rs7588305 and variation in hippocampal volume. This SNP-based association survived multiple-testing correction for the number of SNPs analyzed but not for the number of subcortical structures. Targeting known regulatory regions offers a way to understand the underlying biology that connects genotypes to phenotypes, particularly in the context of neuroimaging genetics. This biology-driven approach generates testable hypotheses regarding the functional biology of identified associations. Hum Brain Mapp 37:1788-1800, 2016. © 2016 Wiley Periodicals, Inc.
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Project description:This study examined the heritability of brain grey matter structures in a subsample of older adult twins (93?MZ and 68?DZ twin pairs; mean age 70 years) from the Older Australian Twins Study. The heritability estimates of subcortical regions ranged from 0.41 (amygdala) to 0.73 (hippocampus), and of cortical regions, from 0.55 (parietal lobe) to 0.78 (frontal lobe). Corresponding structures in the two hemispheres were influenced by the same genetic factors and high genetic correlations were observed between the two hemispheric regions. There were three genetically correlated clusters, comprising (i) the cortical lobes (frontal, temporal, parietal and occipital lobes); (ii) the basal ganglia (caudate, putamen and pallidum) with weak genetic correlations with cortical lobes, and (iii) the amygdala, hippocampus, thalamus and nucleus accumbens grouped together, which genetically correlated with both basal ganglia and cortical lobes, albeit relatively weakly. Our study demonstrates a complex but patterned and clustered genetic architecture of the human brain, with divergent genetic determinants of cortical and subcortical structures, in particular the basal ganglia.
| S-EPMC5011703 | biostudies-other
Project description:The structure and function of the human brain are highly stereotyped, implying a conserved molecular program responsible for its development, cellular structure and function. We applied a correlation-based metric called differential stability to assess reproducibility of gene expression patterning across 132 structures in six individual brains, revealing mesoscale genetic organization. The genes with the highest differential stability are highly biologically relevant, with enrichment for brain-related annotations, disease associations, drug targets and literature citations. Using genes with high differential stability, we identified 32 anatomically diverse and reproducible gene expression signatures, which represent distinct cell types, intracellular components and/or associations with neurodevelopmental and neurodegenerative disorders. Genes in neuron-associated compared to non-neuronal networks showed higher preservation between human and mouse; however, many diversely patterned genes displayed marked shifts in regulation between species. Finally, highly consistent transcriptional architecture in neocortex is correlated with resting state functional connectivity, suggesting a link between conserved gene expression and functionally relevant circuitry.
| S-EPMC4700510 | biostudies-literature
Project description:Subcortical brain structures are integral to motion, consciousness, emotions and learning. We identified common genetic variation related to the volumes of the nucleus accumbens, amygdala, brainstem, caudate nucleus, globus pallidus, putamen and thalamus, using genome-wide association analyses in almost 40,000 individuals from CHARGE, ENIGMA and UK Biobank. We show that variability in subcortical volumes is heritable, and identify 48 significantly associated loci (40 novel at the time of analysis). Annotation of these loci by utilizing gene expression, methylation and neuropathological data identified 199 genes putatively implicated in neurodevelopment, synaptic signaling, axonal transport, apoptosis, inflammation/infection and susceptibility to neurological disorders. This set of genes is significantly enriched for Drosophila orthologs associated with neurodevelopmental phenotypes, suggesting evolutionarily conserved mechanisms. Our findings uncover novel biology and potential drug targets underlying brain development and disease.
| S-EPMC7055269 | biostudies-literature
Project description:Background:Patients with hepatic diseases are treated with numerous drugs metabolized by cytochrome P450. Objective:To evaluate the frequencies of CYP2C19 variant alleles (*2, *3, and *17), genotypes, and phenotypes, and the relationship between the frequency of these alleles and the underlying hepatic diseases among patients with advanced liver diseases who were candidates for liver transplantation. Methods:The Study was conducted on 120 patients suffering from various hepatic disorders, candidates for liver transplantation, and 52 healthy volunteers. DNA was extracted from blood samples and analyzed by TaqMan SNP genotyping assay. The CYP2C19 genotypes were classified into poor, extensive, intermediate, and ultra-rapid metabolizer phenotypes. Results:Viral hepatitis was the most common cause of liver disease among studied patients. The frequencies of CYP2C19 alleles *1, *17, and *2 were 66.7% (160/240), 20.8% (50/240) and 12.5% (30/240), respectively. Allele CYP2C19*3 was not found in the studied population. The most prevalent genotypes were CYP2C19 *1/*1 (47.5%) and *1/*17 (24.2%). The predicted CYP2C19 phenotypes were extensive metabolizer (47.5%), heterozygote extensive metabolizer (45.9%), ultra-rapid metabolizer (5%), and poor metabolizer (1.6%). There was no significant difference between the frequencies of CYP2C19 genotypes between healthy people and patients. The distribution of CYP2C19 genotype frequencies was not significantly associated with the underlying disease conditions (p=0.472). Conclusion:The distribution of CYP2C19 genotype frequencies in Iranian healthy people and patients with various hepatic diseases was not significantly different. This may allow the physicians to predict a tailoring dose regimens based on the individual's metabolic capacity, decrease the risk of harmful side effects of the drugs, and optimize the treatment.
| S-EPMC5839627 | biostudies-literature
Project description:BACKGROUND Cytochrome P450 (CYP) 2C19 is an enzyme involved in the bioactivation of various important therapeutic drugs, from pro-drugs to an active inhibitor of platelet action. Variants in the CYP2C19 gene influence the pharmacokinetics and clinical response to antiplatelet drugs such as clopidogrel; however, there is no available data about the genetic variation of CYP2C19 in the Hakka population in China. MATERIAL AND METHODS A total of 6686 unrelated participants (ages 17-98 years) of self-reported Hakka ancestry admitted at an inpatient department in a hospital in southern China were successfully genotyped by the gene chip platform. RESULTS The identified allele frequencies were CYP2C19*1 (64.33%), *2 (31.06%) and *3 (4.61%). The major prevalent genotype combinations were CYP2C19 *1/*1 (41.73%) and *1/*2 (39.65%). The distribution of CYP2C19 phenotypes was divided into extensive metabolizers (EM) (41.73%), intermediate metabolizers (IM) (45.21%), and poor metabolizers (PM) (13.06%). In the Hakka population, frequencies of the CYP2C19 *2 and *3 variants were observed to be close to those previously identified in Chinese and several other Asian populations. CONCLUSIONS Our study is the first to report on CYP2C19 polymorphisms in the Hakka population, and may help to optimize pharmacotherapy effectiveness by providing personalized medicine to this ethnic group in the near future.
| S-EPMC5757864 | biostudies-literature
Project description:Age-related changes in brain structure result from a complex interplay among various neurobiological processes, which may contribute to more complex trajectories than what can be described by simple linear or quadratic models. We used a nonparametric smoothing spline approach to delineate cross-sectionally estimated age trajectories of the volume of 17 neuroanatomic structures in 1100 healthy adults (18-94 years). Accelerated estimated decline in advanced age characterized some structures, for example hippocampus, but was not the norm. For most areas, 1 or 2 critical ages were identified, characterized by changes in the estimated rate of change. One-year follow-up data from 142 healthy older adults (60-91 years) confirmed the existence of estimated change from the cross-sectional analyses for all areas except 1 (caudate). The cross-sectional and the longitudinal analyses agreed well on the rank order of age effects on specific brain structures (Spearman ? = 0.91). The main conclusions are that most brain structures do not follow a simple path throughout adult life and that accelerated decline in high age is not the norm of healthy brain aging.
| S-EPMC3706494 | biostudies-literature
Project description:PurposeEstrogen metabolizing gene mutations can be associated with defective hormonal signaling leading to disease processes. Endometriosis is an estrogen dependent that can be influenced by defective signaling in the estrogen pathway.ObjectivesTo evaluate the association of A/G 85952 CYP2C19 and A/G 937 HSD17B1 gene polymorphisms with endometriosis through the investigation of a large Brazilian sample of women with endometriosis and a fertile control group.MethodsFive hundred women with endometriosis and 500 women without endometriosis were tested for CYP2C19 and HSD17B1 polymorphisms, by TaqMan Real Time PCR. The results were statistically analyzed by chi-square, logistic regression and tested for Hardy-Weinberg equilibrium.ResultsThe comparison of genotype and allelic frequency of CYP2C19 polymorphism (rs11592737) in patients with endometriosis and control group showed a statistically significant difference (p = 0.0203) and for the HSD17B1 polymorphism (rs605059) differences were not significant (p = 0.0687). Comparing the stages I/II and III/IV endometriosis with the control group for the CYP2C19 we observed p = 0.0133 and p = 0.0564, respectively, and for HSD17B1 the values for p = 0.4319 and p = 0.0667.ConclusionWe observed that CYP2C19 polymorphism is associated with endometrisis in Brazilian women and can be considered a potential biomarker of the disease.
| S-EPMC4294871 | biostudies-literature