MASH and genetics: Why are some people more at risk than others?

Understanding MASH: A metabolic liver disease

Metabolic dysfunction-associated steatohepatitis (MASH), formerly known as non-alcoholic steatohepatitis (NASH), is an advanced form of liver disease linked to the buildup of fat in liver cells.

MASH is part of the broader spectrum of metabolic dysfunction-associated steatotic liver disease (MASLD), a more recent classification that better reflects the metabolic mechanisms involved in these conditions.

In MASH, fat accumulation in the liver is accompanied by inflammation and damage to liver cells. Over time, this inflammation can lead to fibrosis, and in more advanced cases, progress to cirrhosis or liver cancer.

Several factors increase the risk of developing MASH, including being overweight, type 2 diabetes, high cholesterol, and insulin resistance. However, some people develop the disease despite having relatively moderate metabolic risk factors, while others seem to be protected despite having significant risks.

This variability has led researchers to explore the role of genetics in the development of the disease. 

The role of genetics in MASH

Why some people are more at risk

Genetic research has shown that some individuals carry genetic variants that may influence their susceptibility to developing metabolic steatohepatitis.

These DNA variations can affect how the body:

• stores fat in the liver
• processes lipids
• responds to inflammation

As a result, two people with similar lifestyles may have very different risks of developing MASH.

Genetic factors alone do not determine whether the disease will occur, but they can influence how vulnerable someone is to metabolic risk factors. 

The most studied genes

Several genes have been identified as being associated with an increased risk of fatty liver disease and MASH.

One of the most studied is the PNPLA3 gene. A specific variant of this gene is linked to greater fat accumulation in the liver and a higher risk of liver inflammation.

Other genes have also been implicated in disease progression, including TM6SF2, MBOAT7, and GCKR. These genes are involved in different aspects of lipid metabolism and energy regulation.

The presence of certain genetic variants may increase the likelihood of developing fatty liver disease and may also promote progression to more severe forms. 

Genetics and disease progression

Why some forms progress faster

Not everyone with fatty liver disease develops MASH. In some people, the condition remains stable for many years, while in others it can progress to advanced fibrosis.

Research suggests that genetics may also play a role in how quickly the disease progresses.

Certain genetic variants appear to promote inflammatory processes or the formation of scar tissue in the liver. These mechanisms may accelerate progression toward fibrosis or cirrhosis.

Genetics may therefore influence not only the risk of developing the disease but also its long-term course. 

The interaction between genes and lifestyle

Even when genetic factors are present, lifestyle remains a key determinant.

Diet, physical activity, body weight, and metabolic conditions such as diabetes can interact with genetic predisposition.

This interaction is often described as a combined effect: genetics may increase sensitivity to certain risk factors, but those factors are still needed to trigger or worsen the disease. 

Could this lead to more personalised care?

Genetics as a predictive tool

Advances in genetics are opening the door to a better understanding of individual risk in MASH.

In the future, identifying specific genetic variants may help detect people at higher risk of progressing to severe forms of the disease earlier on.

This could allow healthcare professionals to tailor monitoring and prevention strategies to each patient’s profile. 

Research perspectives

Researchers continue to explore the genetic mechanisms involved in MASH.

These findings may contribute to the development of targeted therapies that focus on specific biological pathways involved in disease progression.

Although these advances are still under investigation, they highlight the growing importance of genetics in understanding metabolic liver diseases. 

Conclusion

Metabolic dysfunction-associated steatohepatitis (MASH), formerly known as NASH, is a complex condition influenced by multiple factors.

While lifestyle and metabolic disorders play a central role, research shows that genetics can also influence both the risk of developing the disease and how it progresses.

We are therefore not all equal when it comes to MASH risk. However, even with a genetic predisposition, lifestyle habits remain a powerful way to limit the development and progression of the disease.

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