Non-alcoholic fatty liver disease is the most common liver disease worldwide, with an estimated prevalence of about 25%. This condition is defined by the accumulation of fat in the form of triglycerides in more than 5% of liver cells, known as hepatocytes.
Non-alcoholic fatty liver disease
Non-alcoholic fatty liver disease (NAFLD) is a medical condition in which excess fat accumulates in the liver, but unlike alcohol-related liver disease, this accumulation is not caused by excessive alcohol consumption.
Studies on NASH propose the following non-genetic factors as responsible for the disease:
- Overweight or obesity.
- Certain conditions such as type 2 diabetes mellitus or metabolic syndrome.
- High concentrations of triglycerides or cholesterol.
- High blood pressure.
- Diet rich in fructose, a sugar commonly used to sweeten beverages and foods. The excess of this sugar is converted into lipids and exerts a toxic effect on the liver similar to that produced by an excess of alcohol.
- Changes in the composition and function of the intestinal microbiota (set of bacteria present in the digestive tract that participate in the digestion process).
Symptoms
NASH is a silent disease that stands out for its scarce or absent symptomatology. Generally, it does not cause significant liver damage or complications, although it can cause discomfort due to liver enlargement. However, this disease can progress to non-alcoholic steatohepatitis (NASH), which is characterized by inflammation and liver damage, in addition to the accumulation of fat in the organ. Inflammation and liver damage can lead to fibrosis or scarring in the liver, which can eventually develop into cirrhosis. Characteristic clinical signs of cirrhosis include yellowing of the skin and eyes (jaundice), enlarged blood vessels under the skin, enlarged spleen and red palms.
Prevention
Non-alcoholic fatty liver disease (NAFLD) can be prevented through regular physical activity, a healthy diet and maintaining an appropriate weight. The diet should prioritize foods such as fruits, vegetables, whole grains and healthy fats, while controlling triglyceride and cholesterol levels, and reducing the consumption of fructose-rich beverages or foods.
Number of observed variants
13.5 million variants
Number of risk loci
48 loci
Genes analyzed
Bibliography
Nonalcoholic-fatty-liver-disease. Mayo Clinic [Septiembre 2021]
Miao Z, Garske KM, Pan DZ, et al. Identification of 90 NAFLD GWAS loci and establishment of NAFLD PRS and causal role of NAFLD in coronary artery disease. HGG Adv. 2021 Aug 24;3(1):100056.
Liver disease. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) [April 2021]