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CHEO's world-first ThinkRare algorithm is improving the lives of children, youth, and families by helping to flag some of the youngest patients who may have undiagnosed rare diseases, which answers important medical questions sooner.
Eddy Craig was born just a few days before Christmas 2022. From day one, his mom Ashley says Eddy had difficulties feeding, and he would gurgle and wheeze while trying to breathe.
He was diagnosed with Failure to Thrive, a medical term used when a child does not grow or gain weight normally, and a Chiari I malformation, a structural defect in the cerebellum.
Now two, Eddy has feeding difficulties that require a G-tube, was diagnosed with a congenital heart defect, and he continues to deal with respiratory issues because of his condition.
These health challenges have led to dozens of visits to CHEO across nine clinics and multiple admissions. His family is still learning what Eddy needs and what his future holds.
Then, in September 2024, they received some important answers. His medical challenges and visits to CHEO clinics triggered ThinkRare, a first-in-the-world program that uses an algorithm to scan CHEO’s electronic medical records.
ThinkRare aims to flag kids who may benefit from available genetic testing sooner, which hopefully provides answers and improves their health care journey.
After a series of tests, the family learned in February 2025 that Eddy has Char syndrome — a rare genetic condition characterized by distinctive facial features like Eddy’s, hand anomalies, hearing loss, myopia and/or strabismus, sleep disorders, and short stature.
For Eddy, that diagnosis led to a referral for a sleep assessment, regular dental exams, and yearly vision and hearing tests.
Char syndrome also does not affect development and has a particularly good prognosis. His family hopes Eddy will eventually grow out of most of his symptoms.
“This investigation definitely gave us peace of mind,” said Ashley Craig.
Char syndrome has been reported in only a handful of patients worldwide. Eddy’s health care journey will provide information on whether his symptoms, like feeding issues and Chiari I malformation, are tied to the rare genetic condition.
Eddy’s health has also started taking a turn for the better in 2025. After surgery at CHEO in January, some of his symptoms have improved and he has returned to daycare.
“He's a lot happier than he has been his whole life,” Ashley added.
On the last day of February every year, the world recognizes Rare Disease Day. CHEO is known as a global leader in rare disease research and care, in part thanks to Dr. Kym Boycott, senior scientist at the CHEO Research Institute and chief geneticist at CHEO, who was the principal investigator behind ThinkRare.
“My ultimate vision [for ThinkRare] was to flag, early in a child’s health journey, that they may have an undiagnosed rare genetic disease and could be eligible for genetic testing. Getting kids in for genetic testing sooner can shorten their diagnostic odyssey by years,” said Boycott, who also leads the Care4Rare Canada consortium, and was recently appointed co-chair of the Rare Diseases International Lancet Commission on Rare Diseases.
Her vision has become a reality. The ThinkRare algorithm, which has led to a diagnosis for an impressive 70 per cent of patients tested, will move from the research realm to the clinic in March 2025.
ThinkRare will trigger a clinician-facing alert on the charts of suspected undiagnosed rare disease patients, which means more children, youth and families could receive answers to their diagnostic journey sooner.
All of this was made possible thanks to community donors to the CHEO Foundation who helped make innovative research like ThinkRare a reality, helping to ensure a bright future for kids here and around the world.