Breakthrough by MUHC researcher has major implications for diagnosis, treatment of childhood blindness
Eye Health Month is off to an exciting start, with the recent announcement by MUHC researcher Dr. Robert Koenekoop and his colleagues of a breakthrough discovery in the genetics of childhood blindness. The new study identified the gene most often responsible for LCA (Leber Congenital Amaurosis), the commonest form of congenital blindness. "This discovery represents a significant advance in the fight against this debilitating condition," says Dr. Koenekoop, Director of the McGill Ocular Genetics Centre at the MUHC and Associate Professor in Ophthalmology and Human Genetics at Ï㽶ÊÓƵ. He is also principal co-investigator of this study with Dr. Anneke den Hollander and Dr. Frans Cremers from the University of Nijmegen in the Netherlands.
LCA causes blindness from birth or during the first few months of life. About 600 patients with LCA are currently being diagnosed and managed at the McGill Ocular Genetics Centre of the MUHC, directed by Dr. Koenekoop. The disorder affects one in 30,000 newborns, and is currently incurable. "This is about to change, however," says Dr. Koenekoop. "Our discovery has major implications for improved screening. It also opens avenues for treatment of LCA."
Discovery of the CEP290 gene and a single mutation found in 20 percent of LCA patients will significantly speed up the genetic testing process for blind children. From a therapeutic viewpoint, this discovery adds another pathway for possible therapeutic manipulation and paves the way for a human gene replacement trial of a related LCA gene (RPE65) in early 2007. If this trial is successful, gene replacement therapy may not be far off.
Prior to Dr. Koenekoop's discovery, LCA had been linked to mutations in eight genes. Together, these mutations account for about 45 percent of cases. By studying members of a Quebec family affected by LCA, Dr. Koenekoop's team, which includes research associate and molecular biologist Dr. Irma Lopez, was able to identify a mutation in a gene known as CEP290. This mutation was detected in 21 percent of unrelated cases — making it one of the most common causes of LCA yet identified. The team's research, which was funded by the Foundation Fighting Blindness Canada, was published in the September 2006 issue of the American Journal of Human Genetics.
"The Foundation Fighting Blindness is dedicated to funding the best research in Canada and Dr. Koenekoop's new gene discovery proves that," says Sharon Colle, National Executive Director. "We believe that childhood blindness is intolerable and that cures really are in sight." The MUHC, in collaboration with Dr. Anneke den Hollander and Dr. Frans Cremers from the University of Nijmegen, will continue research into LCA, conducting functional studies of the CEP290 gene and screening more patients for CEP290 mutations.
Quebec is the perfect place to study genetic diseases like LCA. Quebec's population of approximately six million is known as a "founder population" because it can be traced back to a small number (approximately 250) of forefathers. This small gene pool provides the ideal population for the study of genetic disease. "Genetic diseases like LCA are more common in founder populations," says Dr. Koenekoop. "Our patients are enthusiastic about participating in these studies. They realize this research may ultimately lead to improved diagnosis, treatments and cures."
A complete text of this scientific paper can be viewed on the AJHG website (subscription only): .
The Montreal Children's Hospital is the pediatric teaching hospital of the Ï㽶ÊÓƵ Health Centre (MUHC). The institution is a leader in the care and treatment of sick infants, children and adolescents from across Quebec. The Montreal Children's Hospital provides a high level and broad scope of health care services, and provides ultra specialized care in many fields including: cardiology and cardiac surgery; neurology and neurosurgery, traumatology; genetic research; psychiatry and child development and musculoskeletal conditions, including orthopedics and rheumatology. Fully bilingual and multicultural, the institution respectfully serves an increasingly diverse community in more than 50 languages.
The Ï㽶ÊÓƵ Health Centre is a comprehensive academic health institution with an international reputation for excellence in clinical programs, research and teaching. The MUHC is a merger of five teaching hospitals affiliated with the Faculty of Medicine at Ï㽶ÊÓƵ — the Montreal Children's, Montreal General, Royal Victoria, and Montreal Neurological Hospitals, as well as the Montreal Chest Institute. Building on the tradition of medical leadership of the founding hospitals, the goal of the MUHC is to provide patient care based on the most advanced knowledge in the health care field, and to contribute to the development of new knowledge.
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