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Cardiovascular Genetics Center

Today, the Montreal Heart Institute (MHI) Cardiovascular Genetics Centre (CGC) is the only centre in Quebec with a unique and exhaustive expertise in the follow-up of individuals that combines clinical expertise and molecular analysis of genetic cardiovascular diseases. The CGC is composed of two sections: the Genetics Clinic and the Molecular Diagnostic Laboratory.

The mission of the Genetics Clinic is to combine innovative strategies for the diagnosis and management of hereditary cardiovascular diseases with applied knowledge in order to promote preventative healthcare.

The mission of the Molecular Diagnostic Laboratory is to offer, on a provincial scale, a molecular diagnosis service for hereditary cardiovascular diseases.

Specifically, the Centre offers:

  • A clinical evaluation of individuals with a hereditary cardiovascular disease (suspected or diagnosed)
  • Genetic evaluation and genetic counselling for patients and their families
  • Molecular genetic analysis for patients and their families
  • Comprehensive treatment of patients affected with a hereditary cardiovascular disease.

The MHI Molecular Diagnostic Laboratory (MDL) is located within the clinical laboratories, on the ground floor of the Montreal Heart Institute. All MHI laboratories have been accredited by Accreditation Canada with Exemplary Standing. The MDL is part of the College of American Pathologists (CAP) Quality Assurance Program and the European Molecular Genetics Quality Network (EMQN).

A clinical biochemist accredited by the Ordre des chimistes du Québec and the Canadian Academy of Clinical Biochemistry is at the head of the laboratory. The team is composed of a second clinical biochemist also accredited by the Ordre des chimistes du Québec and the Canadian Academy of Clinical Biochemistry, two biochemists (M.Sc. Biochemistry) accredited by the Ordre des chimistes du Québec, one bio-informatician (B.Sc. Bioinformatics), a quality assurance specialist (B.Sc. Chemistry) and two medical laboratory technologists, members of the Ordre des technologistes médicaux du Québec.

Our Services

The MDL is the biggest laboratory of its kind in Canada. The laboratory exists since 2006 and issued over 2,000 personalized reports over the past three years. Working closely with the Genetics Clinic, the MDL performs the genetic analysis of hereditary cardiovascular diseases in order to fulfill various clinical objectives:

The cardiovascular molecular genetic analysis provided by the MDL serves for:

  • Diagnosis confirmation, outcome assessment and treatment guidance for probands;
  • The identification of family members at risk of potentially lethal complications;
  • The determination of the causes of unexplained sudden death.

The laboratory provides a comprehensive service of cardiovascular molecular genetics, including the complete management of specimens by a highly qualified technical and professional staff:

  • Sampling, DNA extraction, sequencing analysis (probands and family members) and individualized classification of each identified variant;
  • Use of cutting edge protocols and devices while maintaining the highest quality standards;
  • Participation in various quality control programmes such as those provided by the College of American Pathologists (CAP) and the European Molecular Genetics Quality Network (EMQN).

Investigated diseases and Associated Tests

Currently, the Molecular Diagnostic Laboratory provides molecular test profiles for the following genetic cardiovascular diseases:

Cardiomyopathies:

Arrhythmias:

Aortopathies:

A detailed description of the diseases and associated molecular test profiles is available when clicking on the name of the disease.

Methods

The Montreal Heart Institute Molecular Diagnostic Laboratory is a strong advocate of quality. The sequence analyses are performed on site in newly built laboratories equipped with cutting edge technology and a highly qualified staff.

Technologies 

The MHI's Molecular Diagnostic Laboratory performs analyses via high-throughput sequencing/massively parallel sequencing, also known as Next-Generation Sequencing (NGS). The library preparation is performed by capture (Nextera) according to the commercial protocol TruSight Cardio Sequencing provided by Illumina. This kit allows targeting genes involved in cardiomyopathies, arrhythmias and aortopathies. We perform the sequencing of coding exons as well as intron/exon boundaries (±1 or 2 pb each side of the exon and -6pb for the first exon) with the MiSeq sequencer (Illumina). Data are analyzed through our personalized Biocomputing workflow. The coverage is at 100%. All coding regions below 30X are verified using Sanger sequencing.

To guarantee quality in the biocomputing of the generated raw data, sequence readings are filtered and trimmed at extremes. A sequencing report is generated for each patient. Sequence readings are then aligned on the reference genome Hg19 (GRCh37.3) with an algorithm adapted to the library preparation. The biocomputing pipeline has been validated with the NIST (National Institute of Standards and Technology) results, the Platinum Genome (Illumina) and samples from the Genome in a Bottle (GIAB) Consortium and was designed to ensure the high quality and stability as well as total traceability of samples.

Complex genomic regions for sequencing are immediately analyzed by Sanger sequencing to ensure the quality of results. These regions are intrinsic to genomes and are composed, for example, of repeated sequences or of segmental duplication already known in the literature or a particularly high or low GC-content. In addition, all clinically relevant identified variants, all regions that do not reach the 30X threshold, and all variants that need to be tested in family members are confirmed by a Sanger direct sequencing method, a world-renowned sequencing method that serves as gold standard.

Analytical Performance :

The average depth of coverage is 300X for NGS. The clinical threshold for depth of coverage is 30X. Analytical sensitivity and specificity are 100% at this threshold. All coding regions below 30X are verified using Sanger sequencing. All reported variants are confirmed by Sanger Sequencing.

Interpretation of Results :
All observed variants are searched in the literature and annotated against a renowned database series such as ClinVar, gnomAD (genome Aggregation Database), dbSNP, 1000 Genomes Project, ESP (Exome Sequencing Project), or any other relevant information sources. In addition, an assessment of the in silico effect of the variant on the protein is performed. The final variant classification is performed following the American College of Medical Genetics (ACMG) criteria (PMID: 25741868, 2015).

Analysis reports do not mention genetic variants normally present in the population (polymorphisms) or unrelated to the disease. However, if future research was to show a deleterious effect of those variants, they could be later reported. All data is therefore preserved in a safe and accessible manner.

Since the laboratory's inception in 2006, a qualified team who has developed a unique and exclusive expertise on site performs all literature reviews and interpretations. The team actively participates in a continuing education program and ensures a constant technological watch. All results are professionally validated by two accredited clinical biochemists.

Descriptive table concerning segmental duplications

Some chromosomal regions are duplicated on the genome with a homology of at least 90% over 1000bp. These segmental duplications affect the quality of the alignment and hence the sensitivity and analytical specificity of variant detection in bioinformatics analysis. These regions represent less than 0.02% of all coding regions of our panels. The following table summarizes the regions corresponding to segmental duplications among our panels.

Gene

Chromosome

Start

End

Exon

TTN

chr2

179519036

179523296

184 à 192

TTN

chr2

179523296

179527557

175 à 183

MYLK

chr3

123415953

123427920

12 à 15

MYLK

chr3

123428286

123435825

11

MYLK

chr3

123435841

123441282

10

CACNA1C

chr12

2790242

2795538

47 à 50

PKP2

chr12

32943682

32945665

13 et 14

CALM1

chr14

90870212

90871921

4 à 6

CALM1

chr14

90870724

90871920

5 à 6

 

To Request a Test :

Forms :
The following documents are required for any test request:

Consent forms :

  • Required Specimen :

We accept whole blood specimens as well as already extracted DNA specimens.

Whole blood :

  • 1x 4.0 mL whole blood EDTA tube (lavender tube)

DNA :

  • 5 µg purified DNA in a 25 µL minimum volume with a D.O. 260/280 ratio between 1.8 and 2.2.
  • The following buffers are accepted: Tris-EDTA (TE) buffer, nuclease-free water and elution buffer provided in a commercial DNA extraction kit.
  • For «Familial Hypercholesterolemia» panel, only whole blood samples are accepted to allow the analysis of large genetic variations - CNV.

Other types of specimens, including molecular autopsy specimens :
For information regarding any other type of specimen, please contact the Molecular Diagnostic Laboratory.

Specimen dispatching :
Double identification (two unique identifiers) is required for all specimens.
First Identifier (required): Full Name 
Accepted Second Identifiers: Date of birth, RAMQ, file number or local specimen number.

Whole blood :
The whole blood tubes are sent at room temperature as per the current transportation standards for biomedical specimens*. The specimens should be received at the latest seven (7) days after the sampling date.

DNA :
DNA samples can be sent at room temperature or in an icebox if the samples were previously frozen at -20°C.*

Other types of specimens, including molecular autopsy specimens :
For information regarding any other type of specimen, please contact the Molecular Diagnostic Laboratory.
*For more information, please read the IATA Dangerous Goods Regulations or Transport Canada’s Standards for Transportation of Dangerous Goods

Shipping Address :
Laboratoire de diagnostic moléculaire
Local C-1760
Institut de Cardiologie de Montréal
5000, rue Bélanger Est
Montréal (Québec) H1T 1C8

The MLD team:

  • Julie Amyot Ph.D. clinical biochemist, Head of Molecular Diagnostic Laboratory
  • Joël Lavoie Ph.D. clinical biochemist
  • Catherine Barahona-Dussault M.Sc. biochemist
  • Guillaume Sylvain-Drolet M.Sc. biochemist
  • Sandra Therrien-Laperrière M.Sc bioinformatician
  • Marie-Claude Magny QA specialist
  • Martine Giguère medical technologist
  • Nathalie Lefebvre medical technologist
  • Marie-Claude Tessier medical technologist
  • Steffany Grondin genetic counselor

For more informations

Address of the Molecular Diagnosis Laboratory

Laboratoire de diagnostic moléculaire
Local C-1760
Institut de Cardiologie de Montréal
5000, rue Bélanger Est
Montréal (Québec) H1T 1C8
514-376-3330 poste 3712
ldm@icm-mhi.org

For more informations