TBP Repeat Expansion Testing
Description
Pathogenic CAG/CAA repeat expansions in the TBP gene have been associated with autosomal dominant spinocerebellar ataxia 17 (SCA17). The pathogenic repeat expansions lead to the expression of a protein with an expanded polyglutamine tract that is thought to confer a toxic gain-of-function.
Pathogenicity is dependent upon CAG/CAA repeat length according to the following ranges 1-4:
Normal Alleles | Mutable Normal Alleles | Intermediate/Uncertain Alleles | Reduced Penetrance Alleles | Full Penetrance Alleles |
25-40 | - | - | 41-48 | 49 or more |
*Pathogenic heterozygous variants in the STUB1 gene may contribute to the variable penetrance of TBP CAG/CAA repeats expansions.
Tests That Analyze TBP Repeats
- Genomic Unity® 2.0
- Genomic Unity® Whole Genome Analysis
- Genomic Unity® Lightning Genome Analysis – Standard
- 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
- Genomic Inform®