BEAN1 (Spinocerebellar Ataxia 31) Repeat Expansion Testing

Description

Pathogenic pentanucleotide TGGAA repeat expansions within an intronic region of the BEAN1 gene have been associated with autosomal dominant spinocerebellar ataxia 31 (SCA31). The pathogenic repeat expansions can form potentially damaging RNA-foci in cerebellar cell nuclei.

Pathogenic repeat expansions result in a 2.5-3.8 kb insertion comprised of 110 TGGAA repeats or more that exist within a TAAAA and TAGAA repeat region. TGGAA repeats have only been reported in affected individuals 1-4.

Normal Alleles

Mutable Normal Alleles

Intermediate/Uncertain Alleles

Reduced Penetrance Alleles

Full Penetrance Alleles

No TGGAA repeats

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Fewer than 110

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110 or more

Note: As SCA31 is typically adult onset, BEAN1 repeat expansions are not reported in minors in comprehensive analyses.

Tests That Analyze BEAN1 Repeats

Additional Resources

First-Line Testing, Lighting Up the Undetectable

A 73-year-old male presented with clinical symptoms suggestive of spinocerebellar ataxia. First-line testing with Variantyx Genomic Unity® 2.0 identified a mosaic BEAN1 expansion.

Case Study: BEAN1 Expansion Provides Spinocerebellar Ataxia 31 Diagnosis

Variantyx Brings the First Combined Short- and Long-Read Whole Genome Sequencing Test to Market with Genomic Unity® 2.0

Press release: Variantyx, a leading molecular diagnostics lab, today announced the launch of Genomic Unity® 2.0, a novel whole genome-based diagnostic test.

Learn More About Ataxia Testing With Variantyx