Metabolic dysfunction-associated steatotic liver disease should not be thought of as a niche hepatology problem. It is increasingly encountered across primary care, diabetes services, cardiology, endocrinology, and population health settings, often long before liver disease is recognised or acted upon.
As our understanding of MASLD evolves, genetics is beginning to offer practical insight into disease heterogeneity and progression risk. PNPLA3 has emerged as one of the most clinically relevant genetic modifiers, with growing evidence that it can refine risk stratification beyond conventional biochemical markers alone.
In this article, Dr Katie Denver explores the role of PNPLA3 in MASLD and considers how genetic insight may support more precise, proactive approaches to liver disease management in everyday clinical practice.
What is MASLD?
- Metabolic dysfunction- associated steatotic liver disease (MASLD) is defined as the presence of hepatic steatosis (>5% on imaging/ biopsy) with at least 1 out of 5 cardiometabolic criteria (obesity, T2DM, hypertension, high plasma triglycerides, low plasma HDL-cholesterol)(1).
- The complex interplay of cardiometabolic, genetic and environmental risk factors drive steatosis, steatohepatitis (MASH) and fibrosis.
- MASLD is the most prevalent chronic liver disease globally, affecting 30% of the adult population, and is one of the most common indications for liver transplantation.
- Beyond major adverse liver outcomes (liver failure, HCC), MASLD has significant downstream effects on cardiovascular disease, kidney disease and various extrahepatic cancers.
PNPLA3 as a genetic driver of MASLD
- Patatin-like phospholipase domain-containing protein 3 (PNPLA3) has emerged as a critical genetic determinant of MASLD.
- PNPLA3 variants are associated with altered lipid metabolism, driving hepatic steatosis, subsequent inflammation and fibrosis(2).
- Gaining insight into the role of PNPLA3 enhances our understanding of the pathophysiological mechanisms that underpin MASLD which may help to shape the emerging therapeutic landscape.
How PNPLA3 shapes clinical outcomes
- PNPLA3 encodes a transmembrane protein (adiponutrin) with triglyceride hydrolase activity which plays a vital role in lipid metabolism within hepatocytes.
- Variants of PNPLA3, particularly the I148M polymorphism has been shown to accelerate hepatic steatosis and increase susceptibility to MASH and fibrosis (3).
- Homozygous carriers of the PNPLA3 I148M variant are more susceptible to liver injury, especially in the presence of associated risk factors such as obesity, insulin resistance, poor diet and female sex (4).
Clinical utility of PNPLA3 in risk stratification for MASLD
- When applied to high pre-test probability patient groups (intermediate FIB-4, T2DM), PNPLA3 genotyping can be applied to define risk profiles and enable tailored monitoring and intervention in patients without cirrhosis.
- In patients with known liver cirrhosis, PNPLA3 genotyping has the potential to enhance HCC risk prediction (5).
PNPLA3 as a therapeutic target
- Currently, there are no approved PNPLA3 therapies for MASLD.
- Silencing PNPLA3 I148M has been shown to improve MASH and liver fibrosis in humanised transgenic mouse models.
- Several ASO and siRNA- based PNPLA3 targeting therapies are advancing through phase 1 clinical trials, with evidence of significant reductions in liver fat content demonstrated (6).
- Further phase 2b studies with histological and non-invasive outcome measures are required to evaluate the effects of targeting PNPLA3 on histological MASH and liver fibrosis to develop novel approaches to precision hepatology.
Conclusion
- MASLD represents a major and growing global health crisis driven by the complex interplay between metabolic dysfunction, genetic predisposition and environmental risk factors.
- In the growing body of literature identifying MASLD- associated genetic variants, PNPLA3 I148M polymorphism has emerged as a key determinant of disease severity and progression.
- Integrating PNPLA3 into current clinical frameworks may refine risk stratification beyond traditional biochemical markers and scoring systems.
- The potential therapeutic targeting of PNPLA3 represents a significant step towards precision hepatology.
References
- Kanwal, Fasiha, et al. “Metabolic Dysfunction–Associated Steatotic Liver Disease: Update and Impact of New Nomenclature on the American Association for the Study of Liver Diseases Practice Guidance on Nonalcoholic Fatty Liver Disease.” Hepatology, vol. 79, no. 5, 9 Nov. 2023, https://doi.org/10.1097/hep.0000000000000670.
- Wentworth, Brian J. “Metabolic Dysfunction-Associated Steatotic Liver Disease throughout the Liver Transplant Cycle: A Comprehensive Review.” Metabolism and Target Organ Damage, vol. 4, no. 4, 26 Dec. 2024, https://doi.org/10.20517/mtod.2024.45. Accessed 27 Dec. 2024.
- Petta, Salvatore, et al. “Impact of PNPLA3 I148M on Clinical Outcomes in Patients with MASLD.” Liver International : Official Journal of the International Association for the Study of the Liver, vol. 45, no. 3, Mar. 2025, p. e16133, pubmed.ncbi.nlm.nih.gov/39412170/, https://doi.org/10.1111/liv.16133.
- Romeo, Stefano, and Luca Valenti. “Fifteen Years of PNPLA3 : Transforming Hepatology through Human Genetics.” Liver International, vol. 45, no. 9, Aug. 2025, https://doi.org/10.1111/liv.70240. Accessed 23 Nov. 2025.
- Chen, Vincent L., and Umberto Vespasiani‐Gentilucci. “Integrating PNPLA3 into Clinical Risk Prediction.” Liver International, vol. 45, no. 3, 16 Sept. 2024, https://doi.org/10.1111/liv.16103. Accessed 13 Jan. 2026.
- Lindén, Daniel, et al. “Targeting PNPLA3 to Treat MASH and MASH Related Fibrosis and Cirrhosis.” Liver International, vol. 45, no. 4, 28 Nov. 2024, pmc.ncbi.nlm.nih.gov/articles/PMC11907219/, https://doi.org/10.1111/liv.16186. Accessed 13 Jan. 2026.