Genetics in non-alcoholic fatty liver disease: The role of risk alleles through the lens of immune response

The knowledge on the genetic component of non-alcoholic fatty liver disease (NAFLD) has grown exponentially over the last 10 to 15 years. This review summarizes the current evidence and the latest developments in the genetics of NAFLD and non-alcoholic steatohepatitis (NASH) from the immune system’s perspective. Activation of innate and or adaptive immune response is an essential driver of NAFLD disease severity and progression. Lipid and immune pathways are crucial in the pathophysiology of NAFLD and NASH. Here, we highlight novel applications of genomic techniques, including single-cell sequencing and the genetics of gene expression, to elucidate the potential involvement of NAFLD/NASH-risk alleles in modulating immune system cells. Together, our focus is to provide an overview of the potential involvement of the NAFLD/NASH-related risk variants in mediating the immune-driven liver disease severity and diverse systemic pleiotropic effects.

Precision medicine in nonalcoholic fatty liver disease: New therapeutic insights from genetics and systems biology

Despite more than two decades of extensive research focusing on nonalcoholic fatty liver disease (NAFLD), no approved therapy for steatohepatitis—the severe histological form of the disease—presently exists. More importantly, new drugs and small molecules with diverse molecular targets on the pathways of hepatocyte injury, inflammation, and fibrosis cannot achieve the primary efficacy endpoints. Precision medicine can potentially overcome this issue, as it is founded on extensive knowledge of the druggable genome/proteome. Hence, this review summarizes significant trends and developments in precision medicine with a particular focus on new potential therapeutic discoveries modeled via systems biology approaches. In addition, we computed and simulated the potential utility of the NAFLD polygenic risk score, which could be conceptually very advantageous not only for early disease detection but also for implementing actionable measures. Incomplete knowledge of the druggable NAFLD genome severely impedes the drug discovery process and limits the likelihood of identifying robust and safe drug candidates. Thus, we close this article with some insights into emerging disciplines, such as chemical genetics, that may accelerate accurate identification of the druggable NAFLD genome/proteome.

Genetic predisposition in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease whose prevalence has reached global epidemic proportions. Although the disease is relatively benign in the early stages, when severe clinical forms, including nonalcoholic steatohepatitis (NASH), cirrhosis and even hepatocellular carcinoma, occur, they result in worsening the long-term prognosis. A growing body of evidence indicates that NAFLD develops from a complex process in which many factors, including genetic susceptibility and environmental insults, are involved. In this review, we focused on the genetic component of NAFLD, with special emphasis on the role of genetics in the disease pathogenesis and natural history. Insights into the topic of the genetic susceptibility in lean individuals with NAFLD and the potential use of genetic tests in identifying individuals at risk are also discussed.