Researchers report the first case of the complete dissection of a complex genetic disorder, Hirschsprung disease, in Nature Genetics.
Hirschsprung disease is an inherited intestinal disorder occurring in 1 in 5,000 individuals. People with the disease lack intestinal nerve cells, resulting in an enlarged colon. Affected individuals have a characteristic distended abdomen as well as constipation, vomiting and enterocolitis.
By combing through the genomes of families with multiple cases of Hirschsprung, Aravinda Chakravarti, Stanislas Lyonnet and colleagues were was able to detect three regions of the genome in which mutations are both necessary and sufficient to cause the disease. The findings offer a complete explanation for both inherited and sporadic cases of the disease. In one of these regions the researchers identified mutations in a gene called RET, which had been previously implicated in the disease. The other two regions harbor genes that are yet to be identified.
Over the past 20 years, molecular geneticists have been successfully identifying the genes that underlie ‘simple’ genetic disorders. In these disorders, a mutation in one gene is usually sufficient to result in the manifestation of each of the diseases. However, the majority of genetic disorders are far from simple and for these it has remained unclear how many genes may be involved. The task of identifying these genes and learning how they interact has represented a daunting task for geneticists. The finding that mutations in what would seem to be three genes are sufficient to cause this complex disorder offers hope that genetic dissection of other complex diseases may be feasible using already established tools. A News & Views article by Eberhard Passarge, who has been investigating Hirschsprung disease for over 30 years, will be published at the same time as the report by Chakravarti and colleagues.
Dr. Aravinda Chakravarti
Johns Hopkins University School of Medicine
Baltimore, MD, USA
Tel: +1 410 502 7525
Dr. Stanislas Lyonnet
Hopital Necker - des Enfants Malades
Tel: +33 1 44 49 51 36
Dr. Eberhard Passarge
Tel: +49 201 723 4560
Also available online: article; News & Views.
(C) Nature Genetics press release.
Message posted by: Trevor M. D'Souza