Researchers at the Hospital for Sick Children say they have discovered the genetic cause of Roifman Syndrome, two decades after the rare congenital disorder was first discovered.

Roifman Syndrome is usually diagnosed in children between 3 and 5 years old and is associated with immune deficiency, abnormal growth of bones and joints, vision problems and cognitive delay.

“I have always promised families that so long as I am working I will try to find the cause of this condition, and my greatest achievement is to now be able to tell the families that we not only have discovered the cause, but we can provide a genetic explanation for many of the key features of Roifman Syndrome,” said Dr. Chaim Roifman, who first discovered the condition 20 years ago. “This is a major leap forward in our pursuit of treatment.”

In a new study published Nov. 2, Roifman says he and other researchers at the hospital have been able to pin-point the gene responsible for the syndrome.

This gene, researchers explained in a statement, actually controls more than 800 other genes, which explains why Roifman Syndrome affects so many parts of the body.

The statement said the discovery will allow children with Roifman Syndrome to be diagnosed early on without having to go through a “long diagnostic odyssey,” preventing unnecessary medical complications associate with the disorder.