ZFHX3 (Spinocerebellar Ataxia 4) Repeat Expansion Testing
Description
Pathogenic GGC repeat expansions in the ZFHX3 gene have been associated with autosomal dominant spinocerebellar ataxia 4 (SCA4) 1. The pathogenic repeat expansions result in an expanded polyglycine tract that may result in toxic protein aggregates.
Pathogenicity is dependent upon GGC repeat length according to the following ranges 2-5:
Normal Alleles | Mutable Normal Alleles | Intermediate/Uncertain Alleles | Reduced Penetrance Alleles | Full Penetrance Alleles |
30 or fewer | - | 31-41 | - | 42 or more |
*Increased repeat length and earlier onset have been observed in successive generations 2.
Tests That Analyze ZFHX3 Repeats
- Genomic Unity® 2.0
- Genomic Unity® Whole Genome Analysis
- Genomic Unity® Lightning Genome Analysis – Pediatric
- 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 Unity® Neuromuscular Disorders Analysis
- Genomic Unity® Neuropathies Analysis
Additional Resources
Longer ZFHX3 repeat lengths correlate with earlier age of onset of SCA4
Poster presentation: Using Oxford Nanopore Technology long-read sequencing we show that long ZFHX3 repeat lengths do correlate with earlier age of onset of SCA4.