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 Healthcare Provider Section

Information on this page is intended for use by a healthcare provider.

If you are a patient, please discuss your questions with your healthcare provider.

Frequently Asked Questions:

Prenatal Genetic Questions:

Cancer Genetic Questions:

General Genetic Questions:


Prenatal Genetic Questions:

How do I order more Prenatal Screening (IPS, MSS) requisitions?

The Prenatal Screening requisitions for Trillium Health Partners - Credit Valley Hospital program can be printed directly from our web site.

My patient's detailed fetal ultrasound revealed a "soft sign". What should I tell her about it?

We are happy to accept a referral (see how to make a referral page) to genetics to review this information in more detail with your patient. Please include the patient's bloodwork (blood group and type, CBC and hemoglobin electrophoresis), ultrasound, and prenatal screening result, if available, with the referral.

For your reference, attached is a copy of our soft signs package that outlines some of the key points discussed during a genetic counseling appointment. Download soft sign package [pdf]»

My patient received a preliminary result from amniocentesis. What does this mean?

At Trillium Health Partners - Credit Valley Hospital we attempt to get preliminary results from amniocentesis to detect numerical anomalies of chromosomes # 13, 18, and 21 (this includes Down syndrome and trisomy 18). This preliminary result is available for over 90% of samples and is available within one week of the procedure. The methodology used to achieve this result has a very high specificity and sensitivity. However, this method cannot detect other numerical chromosome anomalies or structural rearrangements. These can only be determined by complete chromosome analysis which is usually available within 3 weeks of having amniocentesis.
See QF-PCR Fact Sheet [pdf]»

How do I arrange amniocentesis for my patient who is 40 or older at the time of delivery?

If your patient will be 40 years old or greater at the time of delivery and would like amniocentesis, the procedure can be booked by completing the following referral form: Amnio Procedure Referral Form [pdf]»

If your patient has additional family history of a genetic condition, you may wish to consider referring her for genetic counselling.

Note:
As of March 1, 2010, Clinical Genetics is no longer accepting referrals for women whose reason for referral is being 35 years of age, or more, at the time of delivery.
For more information about the testing choices available to you, feel free to view our prenatal screening and testing video». If you have any questions or wish to have one of these tests, please discuss this further with your doctor or midwife. For further information, please refer to Advanced Maternal Age Referrals Memo [pdf]»


Cancer Genetic Questions:

My patient has a family history of cancer. Is my patient eligible for genetic testing?

It is recommended that genetic testing for hereditary cancers should be offered after a genetic counselling session during which time the risks, benefits and limitations of current testing are thoroughly reviewed.
The following is the referral criteria used by most Cancer Genetics Clinics in Ontario. If your patient, and/or your patient's family history meets any of the following criteria, a genetics consultation might be appropriate.

Risk Factors for Inherited Breast and/or Ovarian Cancer:

  1. Multiple cases of breast cancer (particularly where diagnosis occurred at less than 50 years) and/or ovarian cancer (any age) in the family – especially in closely related relatives in more than one generation.
  2. Age at diagnosis of breast cancer less than 35 years.
  3. A family member diagnosed with both breast and ovarian cancer.
  4. Breast and /or ovarian cancer in Jewish families.
  5. Family member(s) with primary cancer occurring in both breasts -especially if one or both cancers were diagnosed before age 50.
  6. A family member diagnosed with invasive serous ovarian cancer.
  7. Presence of male breast cancer in the family.
  8. Family member with an identified BRCA1 or BRCA2 mutation.
  9. Presence of other associated cancers or conditions suggestive of an inherited cancer syndrome.

Risk Factors for Inherited Colorectal Cancer:

  1. Multiple cases in the family of the following cancers related to the Lynch syndrome (Hereditary Non-Polyposis Colorectal cancer – HNPCC) with at least one relative affected with colorectal or endometrial cancer. Age of onset less than 50 years, in closely related relatives and in more than one generation would raise the index of suspicion.
    Gastro-intestinal: colorectal, gastric, small bowel, hepatobiliary, pancreatic.
    Genito-urinary: endometrial, ovarian, kidney, ureter.
    Other: sebaceous (adenoma or carcinoma), brain.
  2. Age at diagnosis of colorectal cancer less than 35 years.
  3. Multiple primary cancers in one family member (see 1. above for tumour sites).
  4. Family member with Familial Adenomatous Polyposis (FAP), or 10 or more adenomatous polyps* (suggestive of attenuated FAP).
  5. Family member with a colonic adenoma or cancer with high microsatellite instability (MSI).
  6. Family member with a known mutation causing either Lynch syndrome (HNPCC) or FAP.

*Adenomatous polyps must be verified by pathological examination.


General Genetic Questions:

What genetic testing should I order for a woman with multiple, unexplained miscarriages?

Chromosome analysis on both the patient and her partner can be ordered by you. If either individual is found to have a chromosome abnormality, then a referral to genetics would be appropriate. Otherwise, you might consider a referral to an obstetrician/gynecologist. To order chromosome testing, the following requisition is available in our secure area: Regional Cytogenetics Laboratory Requisition [pdf]»

I have a couple that is consanguineous and have questions about any risks to their future or current pregnancy. What should I do?

Should the couple already have a child with concerns, or a family history of a known or suspected genetic condition, a referral to genetics is appropriate.

The chance of an unrelated couple having a baby with a mental or physical handicap is about 3-4%. If a couple is first cousins, the chance of having a child with problems is slightly increased to about 5-6%. If the couple is second cousins or more distantly related, the chance of having a baby with problems is similar to the general population.

If there is no family history of a known or suspected genetic condition, additional testing is NOT available for a consanguineous couple. A genetic consultation is not needed.

Does your clinic offer paternity testing?

Paternity testing is not covered by OHIP and as such, we do not provide this service. Paternity testing is readily available in Ontario (an internet search will easily provide appropriate information) and easily arranged by the individual.

My patient has received a positive result on her Ontario Newborn Screen. Should I refer her to you?

No, the Ontario Newborn Screening program is a provincially funded program. Additional information about handling a positive result is available at www.newbornscreening.on.ca.

What genetic tests are available at Trillium Health Partners - Credit Valley Hospital?

The following is a list of genetic tests available through the cytogenetics laboratory and the molecular laboratory. Requisitions for these tests at Trillium Health Partners - Credit Valley Hospital are available for download at secure links:
Regional Cytogenetics Laboratory Requisition [pdf]»
Molecular Diagnostic Laboratory Requisition [pdf]»

Cytogenetics Laboratory:

  • Blood
  • Bone Marrow
  • Amniotic Fluid
  • Tissue
  • Fluorescent In Situ hybridization (FISH)
  • Chronic Myelogenous Leukemia – Diagnostic /Quantitative
  • JAK2

Molecular Laboratory:

  • Alpha-1-Antitrypsin
  • Hemochromatosis
  • Male Infertility (Y microdeletion)
  • Uniparental Disomy
  • Sex Determination
  • Thrombophilia (Factor V, Prothrombin, MTHFR)
  • Hereditary Breast Cancer (BRCA1, BRCA2)
  • Hereditary Colon Cancer (MSI) for HNPCC
  • Familial mutations sequencing (for some genetic conditions)
  • Clonality-B cell/T cell
Are there other genetic tests available?

Other genetic tests are available in the province of Ontario such as Fragile X and Cystic Fibrosis (CF). The molecular laboratory can facilitate send out of these samples to the appropriate provincial laboratory.

Testing for other genetic conditions may be available outside of Ontario. For these tests, a referral to the clinical genetics unit would be available to facilitate counselling and genetic testing.