FIRST-LINE TESTING, LIGHTING UP THE UNDETECTABLE
IriSight® Case Study
Clinical presentation
A primagravida underwent an anatomy scan at 21 weeks gestation. The findings were concerning for skeletal dysplasia, including:
- Foreshortened long bones
- Bilateral bowing of the radius and ulna
- Bilaterally foreshortened ribs
- Low thoracic circumference
Previous genetic testing
No previous genetic testing was reported.
IriSight® Testing
was ordered because of its ability to identify all major variant types in a single test.
Results and interpretation
Variantyx IriSight® testing identified a paternally inherited, likely pathogenic 14.64 kb deletion encompassing KIAA0753 exons 3-7. Along with a second, maternally inherited, pathogenic c.943C>T KIAA0753 variant.
Diagnosis: Short-rib thoracic dysplasia 21 without polydactyly
Uniform data from WGS clearly shows both the partial KIAA0753 deletion (left) and the small sequence change (right).
The Variantyx Difference
Why is “standard” testing not enough? Why is IriSight® the ONLY test that can provide a complete diagnosis?
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The size of both the single nucleotide variant and the 14.64 kb deletion fall below the cut-off value for CMA (~25 kb) and would not have been detected.
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Exome sequencing would have been unlikely to detect the small deletion due to size limitations. While exome sequencing may have detected the single nucleotide variant, on its own the result would have been non-diagnostic and would have required additional testing.
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Without detection of both KIAA0753 variants a diagnosis would not have been possible.
Variantyx genome analysis detects all major variant types in a single test including small sequence changes, mitochondrial variants, repeat expansions and structural variants.
Only Variantyx genome analysis was able to provide a diagnosis, detecting both variants with a single test.
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