Scientists pinpoint genetic origins of Tourette syndrome
The researchers discovered large rearrangements in the genes NRXN1 and CNTN6 in patients with Tourette’s. The study’s results were published in the journal Neuron.
Tourette syndrome is a disorder of the central neural system, characterized by multiple motor and vocal tics. From time to time, patients perform uncontrolled movements and in about 10% of cases blurt out obscene words. About 0.3−0.9% of populations experience this syndrome, with the exposure to the disease being by a factor of 60 higher for the children of such patients. Up to now, the genes which increase the disposition to Tourette syndrome have not been found. According to the scientists, the disease is caused not by a mutation in one gene but by the combination of various genetic factors.
«We have statistically confirmed which genetic changes are linked to the disposition to the disease which provides a chance for better diagnoses,» Vasily Ramensky, a co-author of the study, a research assistant at the Laboratory of Genome Engineering at MIPT Life Sciences Center.
The scientists performed an analysis of genetic data collected from 2,434 Tourette’s patients and 4,093 healthy subjects (the control group). The new revelations show that for patients with this syndrome, the genes NRXN1 and CNTN6 more often undergo rearrangements, that is a duplication of some genome regions and the «falling out» of others. The proteins coded by these genes, neurexin-1 and contactin-6, take part in processes of cell fusion in the neuron system.
The changes affecting NRXN1 have been already described in previous studies devoted to other physical diseases, in particular, adolescent insanity. Now, one can definitely claim that this anomaly increases the exposure to the disease. The duplications in CNTN6 have been, for the first time, linked to Tourette’s although deletions affecting this gene had been already observed in cases of autism spectrum disorders.
According to the researchers, a better understanding of the full genetic nature of Tourette syndrome is coming about step by step. The next goal is to clarify which changes in cells and tissues functioning are caused by disorders in the discovered genes. Knowing these mechanisms will lead to new paths for therapies.