Paris | Monday
SCIENTISTS say they have pinpointed genes that cause a serious intestinal disorder, marking the first time that the multiple genetic causes of a disease have been identified.
Variations in eight genes are implicated in Hirschsprung disease, a condition that affects about one newborn in 5 000, they report in research published online by the specialist journal Nature Genetics.
Individuals with Hirschsprung lack nerve cells in bowel muscles that push faecal material along the intestine and often suffer from a bloated abdomen, constipation, vomiting and bowel inflammation as a result. A team led by Aravinda Chakravarti of Johns Hopkins University School of Medicine, Baltimore, Maryland, and Stanislas Lyonnet of the Necker Hospital for Sick Children in Paris trawled through the genetic profile of families where Hirschsprung was common. In addition to mutations in five genes that cause ”long-segment” Hirschsprung, which affects a long portion of the intestine, they found mutations in three genes that are to blame for ”short segment” Hirschsprung which affects the rectum and a small portion of the colon. Hirschsprung named after a Copenhagen doctor, Harald Hirschsprung, who first identified the condition in 1888 is usually treated by surgical removal of the affected bowel section ”Short segment” Hirschsprung, in which usually only a few centimetres (inches) of bowel are affected, is by far the commonest form of the disease, accounting for up to 85% of all cases.
The research is important because finding the hereditary causes of a disease is a crucial first step towards warning people who are at risk of developing the condition or of passing it on to their children.
The goal is that, eventually, a cure can be found that can block or even reverse the malfunctioning genes.
Scientists have already identified several diseases that are caused by a single gene, such as the fatal brain disorder Huntingdon’s disease, but this is the first time that a multiple-gene condition has been unravelled.
”The approach… should serve as a model for dissecting other complex diseases,” said Eberhard Passarge of Essen University Clinic in Germany, who has been investigating Hirschsprung disease for more than three decades.
”However, a prerequisite for such an analysis is the careful clinical characterisation of the disease to be studied.” – Sapa-AFP