BUFFALO, N.Y. — The Mayo Clinic says about one fourth of the world's population has nonalcoholic fatty liver disease.

Doctors say nonalcoholic fatty liver disease is a common condition caused by fat deposits in the liver cells. They say that the extra fat in the liver cells is not caused by alcohol. There's a subtype of nonalcoholic fatty liver disease called nonalcoholic steatohepatitis, or NASH. Doctors say that occurs when the liver is unable to handle fats and lipids, which then causes inflammatory reactions that lead to damage to liver cells and scar tissue build-up. Further damage could lead to cirrhosis from which patients often end up with liver failure.

The U.S. Food and Drug Administration recently approved resmetirom as the first treatment for NASH.

Dr. Jehad Miqdadi, chief of gastroenterology at Buffalo Medical Group, says previously the only thing physicians could do to treat nonalcoholic fatty liver disease was to recommend a change to healthy lifestyle measures. Those included weight loss, exercise and healthy diet. Miqdadi says this was often hard for patients to follow. He says the new treatment is a breakthrough.

"Basically it acts on a special receptor that is utilized by the thyroid hormone where the action of this medication stimulates the liver to burn energy," said Miqdadi. "And that leads to mobilization of fat out of the liver."

Miqdadi says it also improves scar tissue, which doctors used to think of scarring of the liver as irreversible, but that's not the case. In the future, he hopes for more research in the field and more medications come from that research.