Genetics ever-evolving at NYGH

What goes on in hospital Genetics is misunderstood by many, including by even some health care professionals. Still, genetic testing is often at the root of many important patient care decisions and, every month, North York General Hospital (NYGH) performs thousands upon thousands of tests on blood, amniotic fluid and other biological samples to identify mutations, patterns or changes in chromosomes, genes or proteins. 

“Despite the large volume of tests, we know that each and every one of them is incredibly important,” says Sheri Ferkl, Director of Maternal Newborn, Child & Teen and Genetics at NYGH. “The results can confirm or rule out genetic disorders, helping us to chart a course of treatment for patients and families. These tests can save lives.”

As one of Ontario's largest regional genetics centres, the Genetics Program at NYGH serves the needs of patients through all stages of life: from preconception through to pregnancy, and from childhood through to the adult years. The program provides assessment, diagnosis, and counselling for patients from several regions in the province.

“Genetics is a field that is constantly evolving,” Sheri says. “We've made it a priority to be a leader in the province, be it through influencing changes to policy or being at the forefront of technology.”

New breast and ovarian cancer screening panel

Dr. Wendy Meschino
Geneticist Dr. Wendy Meschino, North York General Hospital

In 2000, the Ministry of Health and Long-Term Care announced that it would fund genetic testing for hereditary cancer — specifically for changes in the BRCA1 and BRCA2 genes that increase the risk of breast and ovarian cancer. BRCA1 and BRCA2 are tumour suppressor genes, and mutations in these two genes account for approximately 3% to 10% of breast cancer cases. Geneticists can look for their harmful mutations in blood samples. 

“This type of testing had a dramatic impact on how we treat hereditary cancers,” says Dr. Wendy Meschino, Geneticist at North York General. “We were able to counsel whole families on cancer risk reduction strategies, such as preventative surgery and further screening tests. Still, families were presenting with histories of hereditary cancers but had negative testing for the BRCA1 and BRCA2 genes, so we knew there were other pieces in the puzzle.”

On April 1, 2017, NYGH's Molecular Genetics Lab introduced an expanded hereditary cancer testing panel and now offers testing for up to 17 genes. These genes often play a role in not just one cancer, but for a host of others. For instance, four genes that increase the risk for ovarian cancer also increase the risk for colon cancer.

“This enhanced screening has helped a lot because many families don't come in just for breast cancer,” says Dr. Meschino. “They come in with a mix of cancers and it can be quite difficult to decide which actual genes to test. By performing a panel, we cover many of the most common hereditary cancers.”

 

family tree

Earlier screening for pregnant women

North York General has always been at the forefront of prenatal screening technology. In 1999, the hospital was among the first health care facilities in the world to offer Integrated Prenatal Screening (IPS), a combination of an ultrasound and two blood tests to estimate a baby's chance of having genetic disorders in pregnancy such as Down syndrome or Trisomy 18. IPS was conducted within both the first and second trimesters of pregnancy. 

“It's a very personal choice to have prenatal screening,” says Dr. Meschino. “Some women want to know ahead of time so they can learn about all of their options and what help is available. Others opt to find out if there are problems at delivery. We respect and support whatever they decide.”

Two years ago, the NYGH Genetics Program reached another milestone by becoming the first in Ontario to provide enhanced First Trimester Screening (FTS). Enhanced FTS is a new first trimester screening test that uses four serum markers from one blood test plus the ultrasound nuchal translucency (portion of skin at the back of the baby's neck) measurement, along with maternal age, to generate a pregnancy specific risk. Patients who have a positive screen result can access further diagnostic tests to confirm whether or not the baby has a genetic disorder. IPS has now been phased out and replaced by enhanced FTS.

“Earlier screening is preferable because it allows expectant mothers with a high-risk result to then have access to non-invasive prenatal testing in the first trimester,” explains Dr. Meschino. “This means that instead of waiting for an amniocentesis — a test that analyzes amniotic fluid which has a risk of a miscarriage — the mother can have a single blood test between 11 to 14 weeks.”

The results of non-invasive prenatal testing, Dr. Meschino says, while not quite as accurate as invasive testing, can check for the most common genetic conditions. “This enables patients to have their information sooner so they're able to explore their options,” she says.

Dr. Meschino is confident that we'll continue to see more breakthroughs in genetic testing in the near future. “The field is evolving exponentially,” she says, “and it's a truly exciting time to be a geneticist. The more thorough the testing, the more we can help patients and families manage genetic disorders in whatever way is right for them. Whatever the outcome of the test, it is incredibly important information.”

This article first appeared in the April 2018 issue of The Pulse. 

Subscribe to receive 10 issues per year of North York General Hospital's community newsletter. 

 

Share this article