MISSED BY OTHERS, DETECTED BY US
Genomic Unity® Case Study
Clinical presentation
A 39-year-old female with a clinical diagnosis of Friedreich ataxia of uncertain origin presented with multiple clinical symptoms including:
- Progressive gait and balance difficulty with juvenile onset
- Paraparesis
- Dysarthria
- Difficulty coordinating upper extremities
- Pain and paresthesia over distal lower extremities
Previous genetic testing
Multiple tests were performed with non-diagnostic results. Including FXN repeat expansion testing that identified a heterozygous expansion of 866 repeats, but no second variant:
- FXN repeat expansion testing
- Ataxia gene sequencing, including FXN
Genomic Unity® Testing
was ordered because of its ability to identify all major variant types in a single test.
Results and interpretation
Variantyx Genomic Unity® testing identified compound heterozygous variants within the FXN gene: the pathogenic repeat expansion and a pathogenic 2,772 bp deletion.
The deletion partially spans the final exon removing coding plus 3’ UTR sequence.
Diagnosis: Friedreich ataxia
Uniform data from WGS clearly shows the deletion.
The Variantyx Difference
Why were these compound heterozygous variants detected by Genomic Unity® testing, and not detected by other tests?
-
Repeat expansions and deletions can not be simultaneously detected by standard tests including gene sequencing, panels and exomes.
Variantyx genome analysis detects all major variant types in a single test including small sequence changes, structural variants, mitochondrial variants and repeat expansions. -
Exon level deletions are not detectable by gene sequencing tests and would be unlikely to be detected by panel or exome tests.
Variantyx genome analysis has a detection range from 1 bp to whole chromosomal events. -
The deletion breakpoints fall within an intron and the 3’ UTR, making the event undetectable by most available technologies – including panel and exome tests.
Variantyx genome analysis includes intronic and untranslated regions, enabling breakpoint detection regardless of location.
Variantyx tests that would have identified these variants
Genomic Unity® 2.0 | Genomic Unity® Whole Genome Analysis | Genomic Unity® Lightning Genome Analysis | Genomic Unity® Exome Plus Analysis | Genomic Unity® Exome Analysis | Genomic Unity® Movement Disorders Analysis | Genomic Unity® Comprehensive Ataxia Analysis | Genomic Unity® Ataxia Repeat Expansion Analysis
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