BEAN1 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 | - | Fewer than 110 | - | 110 or more |
Note: As SCA31 is typically adult onset, BEAN1 repeat expansions are not reported in minors in comprehensive analyses.