Onone out of every 2000 people has a duplicated region of chromosome 16that makes men 23 times more likely to suffer fromextreme thinness, new research reveals. In the case of women, the predisposition is “only” five times greater than that of the rest of the population.
Normally each person has two copies of each chromosome, one from each parent, and therefore also has two copies of each gene. But sometimes fragments of chromosomes are duplicated or lost (deletion), leading to a“abnormal dose” of genes. This could be the case of extreme thinness problems, defined as abody mass index less than 18.5, and that can cause health problems.
In the new study, now published in the journalNatureMore than 100 research centers from around the world have participated, five of which are Spanish. The researchers identified 132 subjects who were carriers of a duplication in a region of chromosome 16p11.2, among whom there was a high frequency of individuals with a low birth weight and a very low body mass index, in many cases accompanied by eating behaviors. selective and restrictive.
Previous studies had already detected that, when thissame region on chromosome 16 is deleted, relates toautism, as well as with a high risk of sufferingmorbid obesity with hyperphagia. The fact that opposite changes (loss and gain of genetic material) in the same region of the genome lead to opposite phenotypes (obesity / underweight), suggests that this region could contain genes that regulate energy balance and affect eating behavior, It can manifest as hyperphagia (increased intake) or anorexia (rejection of food) depending on the number of copies of the genes that the individual has.
