Feasibility of Follow-Up Studies and Reclassification in Spinocerebellar Ataxia Gene Variants of Unknown Significance

Fatemeh Ghorbani, Mohamed Z Alimohamed, Juliana F Vilacha, Krista K Van Dijk, Jelkje De Boer-Bergsma, Michiel R Fokkens, Henny Lemmink, Rolf H Sijmons, Birgit Sikkema-Raddatz, Matthew R Groves, Corien C Verschuuren-Bemelmans, Dineke S Verbeek*, Cleo C Van Diemen, Helga Westers

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

2 Citations (Scopus)
18 Downloads (Pure)


Spinocerebellar ataxia (SCA) is a heterogeneous group of neurodegenerative disorders with autosomal dominant inheritance. Genetic testing for SCA leads to diagnosis, prognosis and risk assessment for patients and their family members. While advances in sequencing and computing technologies have provided researchers with a rapid expansion in the genetic test content that can be used to unravel the genetic causes that underlie diseases, the large number of variants with unknown significance (VUSes) detected represent challenges. To minimize the proportion of VUSes, follow-up studies are needed to aid in their reclassification as either (likely) pathogenic or (likely) benign variants. In this study, we addressed the challenge of prioritizing VUSes for follow-up using (a combination of) variant segregation studies, 3D protein modeling, in vitro splicing assays and functional assays. Of the 39 VUSes prioritized for further analysis, 13 were eligible for follow up. We were able to reclassify 4 of these VUSes to LP, increasing the molecular diagnostic yield by 1.1%. Reclassification of VUSes remains difficult due to limited possibilities for performing variant segregation studies in the classification process and the limited availability of routine functional tests.

Original languageEnglish
Article number782685
Number of pages13
JournalFrontiers in Genetics
Publication statusPublished - 25-Mar-2022


  • functional studies
  • gene panel
  • genetic diagnostics
  • protein modeling
  • segregation
  • spinocerebellar ataxia
  • variant of unknown significance

Cite this