By Sharon Gray
A new gene in psoriatic arthritis has been discovered by a
research team led by Dr. Proton Rahman, a rheumatologist with
the Faculty of Medicine at Memorial and the Health Care Corporation
of St. John’s, and Dr. Dafna Gladman of the University
of Toronto. Memorial University has filed for a U.S. patent
for the novel gene, which focuses on the use of the gene to
diagnose psoriatic arthritis. This long-lasting form of arthritis
is associated with psoriasis and causes skin rashes and produces
painful joint inflammation.
Dr. Rahman’s other co-investigators in this discovery
were Dr. Catherine Alderdice, Dr. Sean Hamilton, Dr. Majed
Khraishi, Donna Hefferton, Yvonne Tobin, Sylvia Bartlett and
Lynette Peddle from St. John’s; Fawnda Pellett, Cathy
Schentag from Toronto; as well as Dr. Dafna Gladman from the
University of Toronto, and Drs. Vernon Farewell and Fotios
Siannis from Cambridge, U.K. The discovery was presented as
a top abstract under the theme New Insights in Rheumatology
at the annual European Congress of Rheumatology in Lisbon,
Portugal, in June 2003, and will be published in the September
issue of the
American Journal of Human Genetics.
Psoriatic arthritis is a less common form of arthritis, occurring
in 0.5 to one per cent of the population, but Dr. Rahman explained
that the incidence may be considerably higher in the Newfoundland
population. “Psoriatic arthritis can occur in up to
20 to 30 per cent of patients with psoriasis, and can range
from being a mild disease to an illness associated with significant
morbidity. At present there is no cure for psoriatic arthritis
and patients are treated with anti-inflammatory drugs and
occasionally drugs that alter their immune system.”
According to Dr. Rahman, there is a growing body of evidence
that psoriatic arthritis has a strong genetic component.
“This disease often runs in families. The homogenous
population in Newfoundland provided an ideal setting to identify
a novel gene for this disease.” Drs. Rahman and Gladman
started studying the genetic basis of psoriatic arthritis
in the Newfoundland population almost four years ago, with
funding from The Arthritis Society, and from the Institutes
of Musculoskeletal Health and Arthritis and Genetics, both
part of the Canadian Institutes for Health Research.
“We congratulate Dr. Rahman and his team for their discovery
of a new gene in psoriatic arthritis, and we commend him for
his ongoing dedication to arthritis research and to improving
the lives of the millions of people with this disease in Canada,
and around the world,” said Denis Morrice, president
and CEO, The Arthritis Society. The society identified Dr.
Rahman as an exciting, up-and-coming researcher early in his
career and has supported his work over the years through its
Research and Career Development Program.
“Proton Rahman’s discovery is the fruit of a funding
collaboration that clearly demonstrates the power we hold
in combining our efforts to support this country’s leading
arthritis researchers,” added Mr. Morrice.
The study led by Dr. Rahman has resulted in the discovery
of the CARD15 gene being associated with psoriatic arthritis.
From analyzing more than 180 individuals with psoriatic arthritis,
Dr. Rahman and his colleagues were able to determine that
this gene is present in about one-third of Newfoundland patients
with psoriatic arthritis. This discovery could pave the way
for better diagnosis of disease, especially in the setting
of psoriatic arthritis in the absence of psoriasis, and potentially
provide a therapeutic target for drug development.
“It also provides further insight into the pathogenesis
of psoriatic arthritis, as the identification of the CARD15
gene in psoriatic arthritis further implicates a possible
infective etiology in the pathogenesis of psoriatic arthritis,”
added Dr. Rahman.
The patent for the CARD15 gene has been filed by Memorial
University’s Genesis Centre, a support network developed
to help Newfoundland and Labrador knowledge-based businesses
and entrepreneurs create high growth enterprises. The patent
application focuses on the potential use of the gene to diagnose
psoriatic arthritis. “For these patients, earlier diagnosis
of the illness will mean earlier medical intervention and
improved disease control,” said Dave King, CEO of the
Genesis Centre. “A potential diagnostic kit to test
for the presence of psoriatic arthritis in patients who may
not be aware they have the disease is a major breakthrough.”
Further details on Dr. Rahman’s work can be found on
the EULAR (The European League Against Rheumatism) Web site
at www.eular.org/eular2003/ and at the Web site for the American
Journal of Human Genetics
www.journals.uchicago.edu/AJHG/
home.html. 
