The genetic inheritance of alcoholism

Answer

Evaluating the Genetic Inheritance of Alcoholism

                The pathophysiology of a disorder is influenced by an array of factors with the two prominent being the environment of an individual and genetics. According to Huether and McCance (1994), understanding the interrelationship between these aspects and the physiology, anatomy, and changes in the functioning of various systems is critical in developing holistic care that considers all patient’s needs. This paper examines the genetic inheritance of alcoholism. The analysis is centred on a review of literature on the topic and evidence-based practice. Literature analysis shows strong evidence regarding the genetic contribution of alcohol misuse and dependence although no candidate gene is robust to demonstrate this relationship.

                Alcoholism remains a public health concern globally. Stickel, Moreno, Hampe, and Morgan (2017) provide the statistical account of this challenge and note that in 2012, the issue resulted in more than 3 million deaths which represented 5.9% globally. This can also be explained as one death in every 20 individuals. Verhulst, Neale, and Kendler (2015) confirm the adverse effects of alcoholism and espouse that Alcohol Use Disorder (AUD) is related to dysfunction of the individual and introduces a wide range of medical sub-functions and co-morbidities. The burden related to the condition is measured in different ways such as the Disability-Adjusted Life Years (DALYs). Essential to note is that alcoholism mainly affects children, the aged, and adolescents as compared to other age groups. The impacts of alcoholism are also reflected in the deteriorated physical health of the individual. Key indicators include obesity, emaciation, poor hygiene, and affecting major body systems such as the liver.

                The genetics of alcoholism can be explained in the familial context. Kendler et al. (2015) note that the familial and environmental aspects are major risk factors in the transmission of AUD in the cross-generational context. Verhulst, Neale, and Kendler (2015) confirm AUD being referred as familial in classical times which is further verified in the modern family studies. In an attempt to explain the genetic and environmental relationship in AUD, Verhulst et al. (2015) note that a number of factors can be explained. These include the impact of gender or sex and social, economic status of the families in influencing the genetics explanation of alcoholism. The genetic and heritability risks of alcoholism are explained in various factors including the consequences of drinking behaviour. However, as espoused by Stickel et al. (2017), it is still not clear which aspects are inherited in alcoholism. This is despite the presence of a comprehensive understanding of alcohol dependence phenotype. The difficulty in explaining the inheritance of these features and especially the involved genes is further centred on the study designs, data used for analysis, and population phenotypes.

                Evidence-based studies explaining alcoholism inheritance are adoption, twin, and family. In family studies, they are centred on the presence of a phenotype among related members being more as compared to by chance. Early studies discovered that individuals from families that misused alcohol were highly likely to demonstrate the same behaviour. Stickel et al. (2017) note the specific statistics explaining this discovery as 49.7% and 22.4% chances of consuming alcohol for male and female individuals that came from families with an alcohol dependence individual. The twin studies which are founded on the addictive genetic risk being shared among the monozygotic twins in full and by half among the dizygotic twins. As espoused by Verhulst et al. (2015), the genetic influence is implied by the high rate of concordance for the interested phenotype in the monozygotic as compared to the dizygotic twins. In the studies conducted on the alcohol abuse phenotypes, the heritability approximates for dependence range between -16% and 72%. Another pertinent fact in these studies is that the hereditability evidence among men is higher as compared to female, especially in the twin studies.

                Alcoholism inheritance can also be explained by adoption studies. The study by Kendler et al. (2015) sought to understand the genetic relationship of alcoholism beyond the biological family context. According to this study, different family constellations and adoptions can be used to explain the transmission nature of parent-offspring. The stepparents are described by the not-lived-with (NLW) relationships. Stickel et al. (2017) confirm that adoption studies alongside twin research demonstrate the significant heritability of alcohol misuse and dependence. However, there are no robust genes discovered to demonstrate this relationship besides the rs1229984 in ADH18 among East Asians, Europeans, and African Americans and the rs671 in ALDH2 which is common among the East Asians (Stickel et al., 2017). Drawing from the literature, two core reasons for candidate gene researches failing to show the relationship between replication are the studies being hypothesis driven and the need to demonstrate that both familial participants were exposed to similar environmental conditions. Notably, these limitations influence future studies.

                In summary, alcoholism is among the leading global public health concerns. Two key factors explaining alcoholism behaviour are the environment and genetics. Various studies have attempted to explain the inheritance of alcoholism. Key findings are that the genetic aspect of alcoholism is familial which implies that there is a high statistical significance for individuals from alcoholism families demonstrating similar behaviour. Three types of studies explaining the inheritance aspect of alcoholism are twin, adoption, and family. The fundamental discovery is that although there is first level evidence regarding the genetic contribution to alcohol misuse and dependence, there are no candidate genes to explain this relationship besides rs1229984 and rs671 in ADH1B and ALDH2 respectively.