22q11 Deletion Syndrome (22qDS)


22q11 Deletion Syndrome (22qDS)

From the colour of your eyes, to the shape of your face, to your height: your genes play a huge part in who you are.

A change in one gene can have many different results, this set of results is called a genetic syndrome. Research has shown a possible connection between some genetic syndromes and mental health problems. While such syndromes have sometimes been hard to detect, accurate diagnosis can help us to better treat and manage them. "The best, comprehensive care for our patients would include informed consideration of genetic issues," says Dr. Eva Chow, a psychiatrist in our Clinical Genetic Research Program (CGRP).

In many cases, CGRP staff can diagnose a specific syndrome. A genetic diagnosis often reveals "undetected health problems and a much more holistic approach to case management," says Dr. Anne Bassett, the director of the CGRP and a Canada Research Chair in Schizophrenia Genetics. "The treatment of associated medical problems, specific information about genetic risks, and an improved understanding of the underlying cause of the psychiatric illness, lifelong learning difficulties and/or physical problems can help the patient, the family and the clinicians involved."

22q11 deletion syndrome (also known as 22qDS; so named because it affects an area on chromosome 22) is a genetic syndrome that affects about one to two per cent of people with schizophrenia. It is the first genetic syndrome that has been directly linked to schizophrenia and can be detected through a blood test.

A major focus of the cgrp is to research this and other genetic links to schizophrenia. Since 1993, Dr. Bassett and her team have been studying 22qDS. They have been following people with 22qDS and collaborating with other hospitals, including the Hospital for Sick Children, the University Health Network and other centres across Canada, to learn more about assessment, treatment and long-term outcomes for the syndrome.

In 2004, Kim Sprague was referred to the CGRP, where he was diagnosed with 22qDS. Throughout his life, he has had some of the health problems that can be part of the syndrome: problems with his heart, kidneys, thyroid, gallbladder, joints, eyesight, hearing and calcium level.

Add this to the onset of his schizophrenia in 1975, and it is obvious that Kim's life, despite the support of family, friends and a team of doctors and other clinicians, has not been easy.

Receiving a diagnosis has not only given Kim and his family a better understanding of his condition, but has also helped with his medical treatment. Calcium and vitamin D supplements have helped reduce feelings of tiredness and edginess, making a big difference in his overall well-being.

The CGRP, which partners with our Schizophrenia Program, sees many patients referred from CAMH and other hospitals for genetic assessment of mental health problems. For example, the Hospital for Sick Children refers older adolescents and adults with 22qDS to CAMH for psychiatric and general care. Community partners such as the Schizophrenia Society of Ontario or the G. Weston Foundation have provided further support, allowing the CRGP to translate research into clinical applications.

Kim Sprague, Client: When I found out, it made sense of the things that were happening. There's an explanation and it's clinical. The syndrome is responsible for all 13 conditions that I have or have had. And, hopefully, one day there will be a cure.


What is Velo-Cardio-Facial Syndrome?

Velo-Cardio-Facial syndrome (VCFS) is a genetic, autosomal dominant condition defined by Shprintzen in 1978. Its frequency is estimated at 1 per 4000 live births. In most patients, a deletion (Figure 2) on chromosome 22q11.2 (Figure 1a and 1b) is responsible for the syndrome. Most of these deletions occur spontaneously (are not inherited from parent to child).

The features of VCFS include cardiac malformations, cleft palate or velopharyngal insufficiency, a characteristic facial appearance, learning disabilities and more than 40 other physical anomalies (Goldberg et al., 1993, http://www.vcfsef.org/facts.html).

Studies indicate that nearly half of individuals with VCFS have mental retardation. Particular problems with abstract reasoning, language delay, mood regulation, monotonous voice, and difficulties in social interaction have been described (Golding-Kushner et al., 1985). A nasal speech tone is observed in the vast majority of individuals with VCFS as well as difficulties with articulation whose origin is assumed to be the cleft palate and pharyngal hypotonia.

Some researchers have described frequent behavioral or psychiatric problems in individuals with VCFS. For example, Shprintzen et al. (1992) observed that 10 to 20% of over 100 patients developed psychotic symptoms (particularly schizophrenia) during adulthood. Papolos et al (1996) also observed a high rate (70-100%) of psychiatric symptoms in 20 children and adolescents. These symptoms were described as similar to those occurring in individuals with bipolar (manic-depressive) disorder.

Within populations of individuals with schizophrenia, researchers have found some carriers of the 22q11 deletion occurring in conjunction with only minimal physical features of the VCFS phenotype.

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