China
Africa
Explore chapters and articles related to this topic
Genetic and environmental determinants of adolescent alcohol use
Published in Ilana B. Crome, Richard Williams, Roger Bloor, Xenofon Sgouros, Substance Misuse and Young People, 2019
Toni-Kim Clarke, Richard C. Crist
Similar results were found for the CRHR1 gene. CRHR1 encodes the corticotrophin response hormone receptor, an important mediator of the endogenous cortisol stress response. Fifteen-year-olds who reported a higher than average number of negative life events showed significant increases in the lifetime rate of heavy drinking only if they had the C/C genotype at the rs1876831 locus (Blomeyer et al., 2008). Carriers of the T allele showed no effect of negative life events on alcohol consumption. Findings in other genes provide evidence that family environment can also negate genetic susceptibility to early alcohol use. A missense SNP (SNP that changes the protein sequence of a gene) in the ANKK1 gene, rs1800497, is associated with alcohol consumption in adolescents from households with permissive parents. Individuals carrying the minor allele of the polymorphism consumed significantly more alcohol than those homozygous for the major allele (van der Zwaluw et al., 2010a). This effect was completely abolished in the presence of parents who set strict rules regarding alcohol. An additional study confirmed this interaction and a similar protective effect in teenagers carrying the G allele of the A118G variant in OPRM1 has been identified (Pieters et al., 2012; Miranda et al., 2013).
A Genetic Framework for Addiction
Published in Hanna Pickard, Serge H. Ahmed, The Routledge Handbook of Philosophy and Science of Addiction, 2019
Philip Gorwood, Yann Le Strat, Nicolas Ramoz
The most studied gene candidate for the dopaminergic pathway is the DRD2 gene that encodes dopamine D2 receptor. Among the DRD2 genes, one variant named TaqIA (SNP rs1800497) with A1 and A2 alleles, was found to be present in many addictions and especially in alcohol dependence. Thus, alcohol dependent patients carrying the A1 allele exhibit a hyposensitivity of dopamine receptors and an increased vulnerability. However, this variant has been considered as a vulnerability gene for alcoholism in more than 60 case-control studies, involving about 20,000 participants, with conflicting results. In fact, the variant of the A1 gene DRD2 polymorphism TaqIA may be a risk factor for experience with alcohol and other psychotropic substances and impulsive or compulsive behavior (Gorwood 2012; Le Foll 2009). Finally, the TaqIA polymorphism was found to be located at the 3’ region of the DRD2 gene, in a new ANKK1 gene, encoding an X-kinase protein that interacts with the D2 receptor to partly control its expression. The ANKK1 gene contains variants also associated with alcohol dependence (Yang 2007). Other variants of the DRD2 gene are also associated with alcohol, heroin and tobacco dependence (Gorwood 2012; Nelson 2013; Ma 2015).
A Treatise on the Role of Herpesvirus in Neurodegeneration
Published in Abhai Kumar, Debasis Bagchi, Antioxidants and Functional Foods for Neurodegenerative Disorders, 2021
Bernard W. Downs, Manashi Bagchi, Bruce S. Morrison, Jeffrey Galvin, Steve Kushner, Debasis Bagchi, Kenneth Blum
The cure for AD remains elusive. More than 5 million Americans are afflicted with AD, a disorder which ranks third, just behind heart disease and cancer, as a cause of death for older people. In addition to herpetic etiological factors mentioned previously, AD is characterized by an increase in dopamine deficits. Competent cognition and memory are dependent on optimal dopamine function. Carriers of the Dopamine D2 Receptor Taq1A, A1 allele (DRD2 A1) have 30%–40% less D2 receptors in the brain than carriers of the DRD2 A2 allele. Recent research has shown among many other maladies that A1 carriers have worse memory performance during long-term memory (LTM) updating compared to carriers of the A2 allele (the other option). A1 allele carriers also exhibit reduced blood oxygen level-dependent (BOLD) dopaminergic signaling and functioning in the left caudate nucleus, which is important for LTM updating. This reduced BOLD dopamine signaling and functioning was observed only in older adults. This suggests an age-related degradation of, with concomitant amplification of aberrant genetic effects on, brain functioning in the elderly. The approximate prevalence of the DRD2 A1 allele among African Americans is 50% based on a subset of African Americans. This is higher than that found in a nonscreened general American population (≤28%) for reward deficiency syndrome behaviors, including addictive, OCD, impulsivity, personality disorders, and many more that are a primary consequence of hypodopaminergia. Based on DRD2 known genetic polymorphisms, the evidence suggests the DRD2 A1 allele increases the risk of AD in aging African Americans carrying it. Research linking this high risk for AD in the African American population, with DRD2/ANKK1-TaqIA polymorphism and neurocognitive deficits related to LTM, can pave the way for novel, targeted pro-dopamine homeostatic treatment that can boost neurotransmitter functional competence, thereby blunting neurodegeneration [80].
Dopaminergic and other genes related to reward induced overeating, Bulimia, Anorexia Nervosa, and Binge eating
Published in Expert Review of Precision Medicine and Drug Development, 2022
Kenneth Blum, Panayotis K. Thanos, Gene -Jack Wang, Abdalla Bowirrat, Luis Llanos Gomez, David Baron, Rehan Jalali, Marjorie C Gondré-Lewis, Mark S Gold
Notably, according to the international classification, the Taq I DRD2 variant is the polymorphism named rs1800497. However, rs1800497 is located 10 kb downstream from the DRD2 gene in the ankyrin repeat and kinase domain containing the 1 (ANKK1) gene. The rs1800497 polymorphism changes the amino acid Glu713Lys in the ANKK1 gene, and these ANKK1 activity changes may provide an alternative explanation for previously described associations between the DRD2 Taq1A RFLP and neuropsychiatric disorders such as addiction [36]. The ANKK1 could inhibit the expression of genes controlled by the NF-KB transcription factor. Furthermore, the DRD2 promoter contains NF-KB binding sites; ANKK1 could, in theory, modulate the expression of the DRD2 gene. This interaction may have some relevance to eating disorders [37].
On the path toward personalized medicine: implications of pharmacogenetic studies of alcohol use disorder medications
Published in Expert Review of Precision Medicine and Drug Development, 2020
Steven J. Nieto, Erica N. Grodin, Lara A. Ray
Alcohol, like most drugs of abuse, increases dopamine release in the ventral striatum. There are five main types of dopamine receptors that are organized into two families, D1-like and D2-like, all of which are G-coupled protein receptors. The Taq1A polymorphism, located downstream of the dopamine receptor 2 (DRD2) and within the Ankyrin Repeat and Kinase Domain Containing 1 (ANKK1) gene, has been shown to moderate treatments in individuals with AUD (see Table 2). Ooteman et al. [49] found that AUD individuals who were A1 homozygotes benefited more from acamprosate versus NTX on cue-induced craving relative to A2 homozygotes, who benefited more from NTX versus acamprosate. In another study of AUD individuals, A1 carriers treated with bromocriptine, a D2 agonist, had lower craving for alcohol relative to A2 homozygotes [69]. Additionally, dopamine can be converted to the neurotransmitter norepinephrine by the enzyme dopamine beta-hydroxylase (DBH). A SNP (rs1611115) in the DBH gene has been shown to moderate NTX responses in AUD individuals. Specifically, NTX-treated T carriers had more abstinence from heavy drinking than those with the CC genotype on NTX [54]. Conversely, NTX-treated C homozygotes had lower abstinence rates compared to placebo-treated C homozygotes. Taken together, genetic variants in the catecholamine system may help identify individuals with AUD who will respond better or do worse on NTX relative to placebo.
Genetic analysis for cognitive flexibility in the trail-making test in attention deficit hyperactivity disorder patients from single nucleotide polymorphism, gene to pathway level
Published in The World Journal of Biological Psychiatry, 2019
Kunlin Zhang, Zili Fan, Yufeng Wang, Stephen V. Faraone, Li Yang, Suhua Chang
Twin studies have estimated a heritability of about 50% for general cognitive ability (Polderman et al. 2006). Candidate gene association studies of cognitive flexibility have focussed on several important neurotransmitter systems, including dopamine, serotonin, norepinephrine and acetylcholine transmitter systems (Logue and Gould 2014). For example, an association of COMT polymorphisms and cognitive flexibility has been reported for schizophrenia (Barnett et al. 2007) and bipolar disorder I (Soeiro-de-Souza et al. 2012). Wishart et al. (2011) found that there was a COMT-ANKK1 interaction associated with cognitive flexibility as measured by the trail-making test. There has been no genome-wide association study (GWAS) for cognitive flexibility.