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My name is Dimitri Stavropoulos.
I'm a Clinical Lab Director at
the Hospital for Sick Children in the Genome Diagnostics Lab,
and Assistant Professor at the University of Toronto in
the Department of Laboratory Medicine and Pathobiology.
I'll be talking today about the "Quantitative CNV Testing in Molecular Diagnostics".
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So the outline of this presentation is a brief review of copy number variants,
a brief history of hereditary genomic rearrangements and disease,
Overview of methods for copy number variant detection,
the criteria that we use to determine if a copy number variant
we identify in a patient is pathogenic or benign,
and a few case examples of the application of these criteria in practice.
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I'll start by talking about
large-scale chromosome rearrangements that
we can typically detect by G-banding analysis.
This slide shows a balanced translocation
between chromosome 2 and chromosome 18 in the maternal chromosomes.
Chromosome 2 is colored in blue and chromosome 18 in orange.
You can see that a part of chromosome 2
is attached to the bottom of one of the chromosome 18s,
and a part of the chromosome 18 is attached to the top of one of the chromosome 2s.
This is a balanced in the parents,
so they don't have a phenotype.
They're apparently normal, but when they have a child,
they are at risk of passing on unbalanced complement of the chromosome 2 or 18 to the child,
which we see here as the proband.
As a result, the proband can have
congenital anomalies or neurodevelopmental abnormalities because they inherited
an extra copy of the part of chromosome 2
that's attached to chromosome 18 as a derivative 18 chromosome.
They also have a missing part at the end
of chromosome 18 from the derivative 18 chromosome.
I just show an example of the carrier type here.
When we identify a patient who has an unbalanced translocation,
we typically do analysis of the parents to see
if it originated from a balanced translocation.
If it has, the recurrence risk is typically about 20 percent.
We offer prenatal diagnosis in future pregnancies in these situations.
