Researchers from the Centre for Research in Environmental Epidemiology (CREAL), an ISGlobal Alliance research centre, and the Department of Experimental and Health Sciences (CEXS) at the Pompeu Fabra University (UPF) have found that a variable region of the genome (an inversion, or part of the genome whose sequence is in reverse order to the normal, in 16p11.2) protects against developing two pathologies jointly: asthma and obesity. It is the first time convincing evidence of the existence of a common genetic variant for these two diseases has been reported.
Another novelty of this article, published in The American Journal of Human Genetics, is the use of new bioinformatics tools (inveRsion) that are capable of analysing the entire genome to identify regions with inversions and to analyse their role in relation to common disease using existing data from previously studied individuals. Inversions are alterations in the genome that may or may not be pathologic.
According to Dr. Juan Ramón González, researcher at CREAL and bioinformatics expert, "Until now, these studies have been very costly because there were no methods for analysing genomic inversions on a massive scale in large populations". On this occasion, data from a total of 5,800 people in Europe, Asia, Africa and America were analysed.
Differences between continents
The results show that the genomic region analysed varies according to the continent from which the person comes. "This is an example of how changes in the genome can be selected depending on how humans adapt to their environment, in this case, their metabolic needs in relation to climate," says Dr. Luis Pérez-Jurado, a researcher from the Genetics Unit and the Department of Experimental and Health Sciences at Pompeu Fabra University (UPF), and the Network Centre for Biomedical Research on Rare Diseases (CIBERER).
Specifically, only 10% of the population of East Africa has this genomic inversion and 50% of the population of northern Europe (where it is assumed that this alteration has been selected for better adaptation to the cold climate, which requires a higher basal metabolic rate).
Overall, after studying 5,800 people, this genetic variant explains 40% of the genetic "protection or predisposition" to developing asthma and obesity simultaneously.
"We are currently using the methods we have developed to study the role of over a hundred inversions in other diseases. Specifically, we are now studying some inversions that seem to predispose to developing autism or intellectual disabilities, among others", says the CREAL researcher.