A genetic discovery that could be a bit easier to swallow
A mysterious disease that causes nerves in the oesophagus to disappear, preventing food from entering the stomach, has been found to be autoimmune in origin.
Researchers have long been confounded about what causes the rare complaint, which afflicts around one in every 100,000 people.
The condition, known as achalasia, causes nerve cells in the oesophagus – including those that control the opening and closing of the sphincter at the opening to the stomach – to gradually disappear. Eventually, the sphincter locks shut, causing food to accumulate in the oesophagus.
Treatments have typically involved either forcing the sphincter open using a balloon inserted endoscopically, or surgically cutting it, but understanding the cause has for years remained elusive.
But an investigation by researchers at KU Leuven in Belgium and Germany’s Bonn University, published in the journal Nature Genetics, has provided strong support for long-held suspicions the condition is autoimmune in origin.
Using DNA samples from 1506 achalasia patients and 5832 healthy volunteers, the researchers identified 196,524 tiny differences – single nucleotide polymorphisms (SNPs) – in the immune-related DNA of those with the condition, and compared them with those of the healthy subjects.
As a result, they identified 33 SNPs associated with achalasia, and all were located in the region of the human genome known to be associated with other autoimmune disorders such as multiple sclerosis and type 1 diabetes.
This evidence has led the researchers to conclude the condition is an autoimmune disease.
In the course of their investigations, the scientists pinpointed a string of amino acids inserted in the DNA of those with achalasia, opening a promising avenue for the development of a treatment and possible cure.