Fatty Liver Disease Is Actually Five Distinct Conditions, Study Finds

The disease is a major driver of cirrhosis, liver cancer and liver transplantation worldwide. Why some patients deteriorate while others don't has puzzled researchers for years. This study offers a partial answer: they may simply have different diseases.

**Takeaway: the severity gap between patients may reflect different underlying biology.

What made the discovery possible?

Scale. The team used Mayo Clinic's Research Data Atlas, a platform that links patients' genetic information with their medical records. Dr. Eric Klee, co-senior author, helped build it.

The platform draws on the Tapestry Study, which produced Mayo Clinic's largest collection of exome data — more than 100,000 participants. An exome is the slice of DNA containing instructions for making proteins, the molecules that carry out most of the body's essential work. Reading it reveals inherited differences that shape how disease starts and progresses.

"When clinical and genomic data are analyzed together at this scale, you begin to see patterns of disease progression that would otherwise remain hidden," said Dr. Shulan Tian, co-senior author and a Mayo Clinic bioinformatician. "Once you separate these subtypes, you can start to match treatments to the biology that's actually driving the disease."

Dr. Klee put it this way: the approach "helps us map complex disease with such precision that we can begin to anticipate its course and intervene before the most serious damage occurs."

**Takeaway: pairing DNA with medical records at massive scale exposed differences no single-patient exam could catch.

What about depression, sleep apnea and migraines?

The subtypes differ beyond the liver. For the first time, researchers linked particular MASLD subtypes with depression, sleep apnea and migraine.

That doesn't prove fatty liver disease causes those conditions. It does suggest the biological processes behind certain forms of the disease may reach across multiple body systems.

**Takeaway: liver health may be more entangled with brain and sleep disorders than doctors assumed.

Could this change treatment?

Eventually, yes — with caveats. The findings are preliminary. Doctors aren't subtyping patients in clinics yet.

The goal is clear: use genetic and clinical data to identify each patient's subtype, flag who's most vulnerable — including people with few conventional risk factors — and match treatment to the biology at work.

"When you connect genetic data with detailed clinical information across large populations, you can start to redefine diseases in ways that directly impact patient care," said Dr. Konstantinos Lazaridis, the Mayo Clinic individualized medicine executive who led the Tapestry Study and co-authored the work.

Next steps are already planned. The team wants to validate the results in larger, more diverse populations and test whether subtypes respond differently to existing drugs, including GLP-1 receptor agonists — medications used for type 2 diabetes and obesity.

If those studies pan out, fatty liver care could shift toward precise screening, earlier intervention and treatments tailored to each patient's underlying biology.

**Takeaway: five subtypes could one day mean five different treatment paths — once confirmation studies arrive.