Which factors determine body size besides genetics?

What makes people grow

Vienna - Dutch men and Latvian women are relatively tall, Indonesian men and Bolivian women are rather short. Such rankings are known and of course allow conclusions to be drawn about environmental influences on the growth of a child. In the west, people tend to grow taller. The central genetic component of body growth has now been examined in more detail in a study with over 700,000 participants in which DNA was taken from all test subjects.

No fewer than 83 rare genetic variations were discovered that influence body size. Although we already know several hundred genetic changes with a similar effect, it seems to be precisely the newly recognized modifications that make the difference - according to studies, they are likely to determine whether people are two centimeters taller or shorter.

Adult size is determined by genetic information contained in our DNA. That is why children of great parents also grow up or even outgrow them. The study, carried out by Queen Mary University London, the Montreal Heart Institute, the Broad Institute in Boston and the University of Exeter in southwest England, now offers new insights into human skeletal growth that go well beyond this knowledge. The identified genes should help to assess the risk of stunted growth and feed the hope that approaches of personalized medicine against stunted growth can be used. Three to five percent of all newborn children are affected.

Nevertheless, one still seems to be a long way from fully answering the question of which genetic factors influence body size. One speaks of a quarter of the knowledge that is actually necessary. "A fascinating but still poorly understood part of human biology," said Andrew Wood of the University of Exeter.

The study also highlights new gene candidates and biological pathways involved in growth. For example, the researchers focused on two changes found in a gene called STC2. This variation could only be identified in one person in a thousand. The scientists emphasized that they are still a long way from any clinical applications. Guillaume Lettre from the University of Montreal said they used the size of adults to show how different people are.

The study, which is the largest of its kind to date, was carried out with data from the British biobank, which also documents lifestyle and diseases. The subjects were followed over a longer period of time. (red, 02/02/2017)