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May 21, 2024

Longer ZFHX3 repeat lengths correlate with earlier age of onset of SCA4

For years scientists believed they knew where the causal gene for spinocerebellar ataxia (SCA4) could be found, but the identity of the precise gene remained a mystery. Recently, two publications finally provided the answer: ZFHX3 1,2. Individuals with SCA4 show expansion of the GGC repeat located within the final exon of ZFHX3, combined with a loss of interrupting sequences.

At Variantyx, we’re always striving to better understand and detect more disease-causing variants – especially repeat expansions. Which is why we recently collaborated with author Andreas Puschmann of Lund University, and his graduate student Joel Walleneus, on a follow up study to evaluate whether greater repeat length may be correlated with earlier onset and greater severity of symptoms. The results of this work are being presented as a poster at the World Congress of Parkinson’s Disease and Related Disorders being held in Lisbon, Portugal May 19-22, 2024.

Using Oxford Nanopore Technology long-read sequencing we show that long ZFHX3 repeat lengths do correlate with earlier age of onset of SCA4.

At Variantyx, we’re proud to be the first lab to offering ZFHX3 expansion testing which is included as part of our comprehensive analyses as well as a number of relevant, targeted neurology analyses:

Comprehensive analyses
Genomic Unity® Exome Analysis
Genomic Unity® Exome Plus Analysis
Genomic Unity® Whole Genome Analysis

Targeted analyses
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


  1. Am J Hum Genet. 2024 111(1):82-95. (PMID: 38035881)
  2. Mov Disord. 2024 Jan 10. Online ahead of print. (PMID: 38197134)