[Alcoholic liver disease: the roles of genetic-epigenetic factors and the effect of abstinence].

The pathogenesis of alcoholic liver disease depends not only on the toxic effects of alcohol, but also on the complex interaction of host's and environmental factors. Thus, the genetic pre-disposition, co-morbidities and behavioral factors all play a role in the individual variations in the disease outcomes. On the other hand, the essential part of the therapeutic strategy is the complete withdrawal of the harmful etiological agent. The present paper is devoted to overview the genetics, the environmental factors and the effects of abstinence in alcoholic liver disease. Genetic variants in two enzymes involved in the metabolism of ethanol, alcohol-dehydrogenase ADH1B *2 and aldehyde-dehydrogenase ALDH2 *2 through increasing the blood level of acetaldehyde, may play a "protective" role against alcoholism. The P450 CYP2E1 *5 c2, an inducible microsomal oxidase, upregulated by ethanol and by formation of acetaldehyde and reactive oxygen species, increases liver toxicity. Three novel gene polymorphisms - such as the patatin-like phospholipase domain-containing 3 (PNPLA3 I148M C>G), the transmembrane 6 superfamily member 2 (TM6SF2 E167K), and the membrane-bound O-acyltransferase domain-containing 7 (MB0AT7 rs641738 C>T) - have been proven as risk factors of steatosis, fibrosis and even hepatocellular carcinoma in both alcoholic and non-alcoholic fatty liver disease patients. Alcohol-induced epigenetic effects, reversible but inheritable gene expression alterations - as histon modulations, DNA methylation and micro-RNA-s - are of importance in the pathogenesis as well, and in the future, they may serve as diagnostic markers and therapeutic targets. Women are at greater risk of developing alcoholic cirrhosis, furthermore, malnutrition, obesity, diabetes, smoking, and hepatitis virus infections are also risk factors. Alcoholic liver disease should be regarded as a preventable disease. Several clinical studies revealed that abstinence may result in the regression of steatohepatitis and fibrosis, compensation of cirrhosis, improving disease outcome and increasing survival even in patients with advanced stages. Early diagnosis and multidisciplinary interventions are highly required to achieve long-term abstinence and to prevent alcoholic cirrhosis. Orv Hetil. 2019; 160(14): 524-532.