According to a recent announcement by the German Centre for Diabetes Research (DZD), approximately 18 million people in Germany suffer from non-alcoholic fatty liver.
The causes of this disease are manifold and include environmental as well as genetic factors.
According to the German Liver Foundation, about one third of all adults have a liver enlarged by fat storage – and the number is constantly increasing.
A distinction is made between non-alcoholic fatty liver (NAFL) and alcoholic fatty liver (AFL).
Among the causes, which usually lead to fatty liver in combination, are incorrect nutrition, lack of exercise and overweight, high alcohol consumption or even diabetes.
Researchers have now discovered another cause.
Although many people quickly think of alcohol when they hear the term “fatty liver”, there are also completely different causes for fatty liver disease.
Researchers have now discovered another genetic trigger for non-alcoholic fatty liver (NAFL).
Non-alcoholic fatty liver: Further genetic cause discovered
DZD scientists have now discovered new genes that play a role in the development of fatty liver.
The genes IRGM, Ifgga2 and Ifgga4 are responsible for the production of regulatory proteins of the family of immune-associated GTPases in humans and mice, respectively, which counteract fat accumulation in the liver.
However, genetic modification leads to the production of fewer of these proteins.
About 18 million people in Germany affected
The results were recently published in the Journal of Hepatology.
According to the DZD, nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in Europe and the USA.
In Europe, about 20-30 percent of the population suffer from this disease.
In addition to an unhealthy lifestyle with a diet rich in fat and sugar and a lack of exercise, a genetic predisposition is also responsible for the development of this liver disease.
NAFLD is often associated with other diseases such as obesity, type 2 diabetes, hypertension and dyslipidemia.
In humans and also in mice, these genes are responsible for the production of regulatory proteins of the family of immune-associated GTPases, which counteract fat accumulation in the liver.
NAFLD is a complex disease for which there is not only one disease gene.
Rather, the interactions of different genes and epigenetic factors play a role.
Researchers have now discovered a new family of genes that play an important role in preventing fatty liver development.
According to the researchers, molecular markers and statistical methods (QTL analysis, quantitative trait locus) in mouse strains can be used to identify genes that cause complex human diseases.
For example, the research team discovered a region on mouse chromosome 18 that was associated with altered amounts of fat in the liver.
When the Ifgga2 and Ifgga4 genes are read, proteins of the immune-associated GTPase family are formed – in the mouse the protein IFGGA2 and IFGGA4 and in humans the protein IRGM.
The study was conducted by a research team of the German Institute of Human Nutrition Potsdam-Rehbrücke (DIfE), the German Diabetes Center (DDZ) and Helmholtz Zentrum München – all partners of the DZD.
However, if a genetic modification is present, fewer proteins are produced.
Studies show that the liver of patients with NAFLD and mice with fatty liver shows significantly lower amounts of these proteins.