Scientists at the University of Bonn, together with colleagues from Romania, have discovered a gene variant that significantly increases the risk of developing gallstones (Hepatology No. 46, 11 July 2007, DOI 10.1002/hep.21847).
It is estimated that one in ten Europeans has this variant in their hereditary disposition. For those affected, the likelihood of developing a gallstone in the course of their life is two to three times higher.
The relevant gene contains the instructions for building a molecular pump which transports cholesterol from the liver into the bile ducts – cholesterol being the substance from which most gallstones are formed. The genetic modification appears to cause this pump to work permanently at high speed. Gallstones are a common disorder: in Germany alone more than 170,000 gallbladder operations a year are performed.
Gallstones occur very frequently, affecting 15 to 20 per cent of all Germans, usually without noticeable symptoms. But in around a quarter of cases the stones will announce their presence at some time in the form of a painful colic. In the end they often have to be operated. "Gallstones are among the gastrointestinal problems that incur the highest treatment costs," says Professor Dr. Frank Lammert, the Bonn-based specialist for internal medicine.
Gallstones tend to be found at high levels within certain families. In particular, studies of twins provide evidence of a genetic component that boosts risk levels. "We reckon that environmental influences, like the wrong diet, are 70 to 80 per cent responsible for the disorder," explains Lammert who works in the university hospital's Department I headed by Professor Dr. Tilman Sauerbruch. "The rest is caused by genes."