FIRST-LINE TESTING, LIGHTING UP THE UNDETECTABLE
Genomic Unity^® 2.0 Case Study

Long-read sequencing delivers an SCA31 diagnosis

Clinical presentation

A 73-year-old male presented with clinical symptoms suggestive of spinocerebellar ataxia, including:

No previous genetic testing was reported.

was ordered because of its ability to identify all major variant types in a single test.

Variantyx Genomic Unity^® 2.0 identified a fully expanded, mosaic, BEAN1 allele with 85-120 TGGAA repeats.

A homozygous, pathogenic GAA variant and a heterozygous, pathogenic BRCA2 variant were also identified as ACMG secondary findings.

Diagnosis: Spinocerebellar ataxia 31

Uniform data from long-read WGS clearly identified the mosaic BEAN1 expansion. The GAA and BRCA2 variants are not shown.

Why was this BEAN1 expansion detected by Genomic Unity® 2.0 testing, when it would have been missed by other tests?

Repeat expansions can not be detected by standard genetic tests, including panels and exomes. And even most genomes.
Variantyx genome analysis detects all major variant types in a single test including small sequence changes, structural variants, repeat expansions and mitochondrial variants – which is critical for first-line testing of ataxia patients.
Repeat expansions can be detected by PCR and Southern blotting, but BEAN1 would have to be specifically targeted. Very few available ataxia tests are able to overcome the challenges of this locus.
Variantyx genome analysis detects repeat expansions in >35 genes, including 17 ataxia genes. When Genomic Unity^® 2.0 testing is selected, the parallel use of long-read sequencing extends the analysis to 7 additional repeat expansion genes, including BEAN1.
Variantyx is one of the first labs to offer BEAN1 testing.

Connect with a Clinical Specialist to find out how easy it is to bring the power of whole genome sequencing into your practice.