TORONTO, May 12 /CNW/ - A new study involving Canada's Centre for
Addiction and Mental Health (CAMH) has found a gene connected with a
type of intellectual disability called Joubert syndrome.
CAMH Senior Scientist Dr. John Vincent has identified this gene that,
when defective, leads to Joubert syndrome. This research is published
in the May 13 issue of Cell.
This international study combined Dr. Vincent's gene mapping of a family
with Joubert syndrome, with the use of a protein network map
established by researchers at Genentech Inc., Stanford University and
the University of California at San Francisco (UCSF). Together this
approach identified two genes associated with group of disorders called
Joubert syndrome, which is a ciliopathy, affects brain functioning,
resulting in intellectual deficits, movement and coordination problems
and other symptoms such as kidney and eye problems. This syndrome is
reported to affect approximately 1 in 100,000 children, although this
is likely to be a significant underestimate of the true prevalence.
Ciliopathies are caused by genetic defects to a part of the cell called
the cilium. The cilium is crucial as it is involved with cell signaling
pathways during cell development in different parts of the body. The
other ciliopathy gene identified in this study leads to a condition
called nephronopthisis, which is also associated with kidney and eye
"A defect in any aspect of this molecular pathway may have very similar
effects at the clinical level," says Dr. Vincent, who is also head of
the Centre for Addiction and Mental Health's Molecular Neuropsychiatry
and Development Laboratory.
Dr. Vincent's team found defects in the TCTN2 gene occurring in a family in Pakistan, in which four siblings had
Joubert syndrome. The syndrome occurs when a child inherits a defective
copy of the gene from each parent.
The researchers based in California led the mapping of a network of
potential proteins related to ciliopathies that interact on common
pathways, as an approach to identify the disease genes.
The study was a collaboration of researchers from six countries and more
than a dozen centres. The lead authors were Peter Jackson and Liyun
Sang at Genentech and Jeremy Reiter at UCSF, and other collaborators
included Friedhelm Hildebrandt at the University of Michigan at Ann
Arbor, Dan Doherty at the University of Washington in Seattle, and
Muhammad Ansar of Quaid-e-Azam University in Islamabad, and Julie
Miller at Stanford University.
Dr. Vincent previously discovered the CC2D2A gene, which is also associated with Joubert syndrome. Defects on this
gene account for about nine per cent of cases of Joubert syndrome. To
date, 10 genes have been connected with Joubert syndrome.
The Centre for Addiction and Mental Health (CAMH) is Canada's largest
mental health and addiction teaching hospital, as well as one of the
world's leading research centres in the area of addiction and mental
health. CAMH combines clinical care, research, education, policy
development and health promotion to help transform the lives of people
affected by mental health and addiction issues.
CAMH is fully affiliated with the University of Toronto, and is a Pan
American Health Organization/World Health Organization Collaborating
SOURCE Centre for Addiction and Mental Health
For further information:
Media Contact: Michael Torres, Media Relations, CAMH; 416-595-6015