Researchers out of British Columbia have managed to identify the genetic underpinning of certain intellectual disabilities in children, which one parent has described as lifesaving.

The genetic screening study, published in the New England Journal of Medicine on Wednesday, showed that researchers out of BC Children’s Hospital and the University of British Columbia were able to diagnose 68 per cent of the 41 families in the study with a precise, underlying genetic condition, and offer targeted treatments to the children in more than 40 per cent of cases.

The researchers also discovered 11 new disease genes.

"This research is very encouraging because for a subset of patients we can identify the genetic underpinning of their intellectual disability and then determine the right intervention,” lead author, paediatrician and biochemical geneticist Dr. Clara van Karnebeek said in a news release. "There’s a bright future ahead for personalized medicine informed by genetic diagnosis."

Michelle Gentis' 15-year-old son Joshua was one of the individuals involved in the study.

She said Joshua lived most of his life without knowing the cause of disabilities, which prevent him from speaking and cause him difficulties with balance and gross motor function.

Gentis said Joshua was developing normally until he was about six or seven months old.

"At that point he couldn't sit up, and I began to wonder, what's going on?" Gentis told CTV News.

Van Karnebeek said the noticeable improvement in the conditions of children like Joshua is very encouraging.

“Of course the most gratifying part of this study is that it has true impact,” she told CTV News.

The researcher said she has seen improvements in a wide variety of symptoms caused by intellectual disabilities.

“Some children who have received the diagnosis which enabled us to start neurotransmitter supplements -- their behavior has improved from self-injuring…thousands of times a day, not being able to watch a movie or have dinner be part of the family life,” she said. “Through the treatment they have calmed down, become happier children who have time to develop (and) can spend time with their family.”

Many participants started experiencing fewer seizures, she said, and many of those with dystonia and other muscular disorders were able to better use their limbs.

Van Karnebeek said researchers have also seen a “dramatic” improvement in communication skills among other participants.

B.C. mom describes painful road to a diagnosis

Gentis said the road to finding a diagnosis was a long, painful and expensive one.

When he was two years old, doctors said Joshua's cerebellum was not developing normally, and that was the cause of his gross motor difficulties. But doctors were unable to give the family a precise diagnosis.

"A diagnosis is so important for funding, for education, for medical treatment," Gentis said.

She said Joshua's education suffered because of a lack of a diagnosis.

"When you're unable to speak, people assume that you are not intelligent," Gentis said. "(But) day in and day out, he demonstrated that he is smart, and he understands everything."

Once Joshua was enrolled in the study, Gentis said it only took about six months for the researchers to diagnose his condition through genetic testing.

Joshua has been diagnosed with H ABC syndrome -- a condition that affects the part of his brain that controls motor skills, balance and muscle coordination. There are less than 100 known cases in the world.

Gentis was relieved to hear that the condition does not impair cognitive function.

"Now it's not just me saying to the school system, 'No really, he is really smart', she said. "We need to treat him as a student who is able to learn, and the impact of that on his life is incomprehensible."

The diagnosis meant that doctors were able to adjust Joshua's medication, and Gentis said she's seen a "significant" improvement in his symptoms.

Researchers involved in the study noted that some of the patients responded to simple interventions like dietary changes and vitamin supplements, while others needed more invasive treatments like a bone marrow transplant.

During the study, researchers discovered a new genetic disease that presents itself in early childhood with life-threatening sleepiness and coma due to a build-up of toxins in the body. The researchers also discovered a new metabolic disease that affects the brain and is characterized by small head size, seizures, and developmental delays.

Van Karnebeek said the hospital is now working with experts around the world to make sure these new conditions are considered when newborns are screened for intellectual disabilities.

Researchers were able to pinpoint treatments to improve the symptoms in both diseases.

"We’re learning more about brain function and the mechanisms underlying intellectual disability," van Karnebeek said. "These results are meaningful to individuals around the world who suffer these rare conditions."

Gentis, meanwhile, said the researchers' ability to provide a diagnosis in these rare medical cases is lifesaving.

"You're giving a young man the hope for a future," she said. "Hope that he can be part of the workforce and be a contributing member of society."

The study has now expanded to include 250 families, van Karnebeek said, calling the research a “model for other rare diseases.”

Ultimately, she said the goal of the research is to achieve quicker, more accurate diagnoses and help more children whose diseases were not properly understood in the past.

“These children and the families all deserve to know what the underlying cause (of the disability is) is,” she said. “This would mean, across Canada, thousands of children each year should have access to this kind of testing and should be screened for this. If it remains a mystery diagnosis…then this (genetic) testing is definitely the way to go.”

With a report from CTV's medical specialist Avis Favaro and producer Elizabeth St. Philip