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Updated: Jan 8, 2026
Quantitative Approaches for Studying Cellular Structures and Organelle Morphology in Caenorhabditis elegans
Published on: July 5, 2019
Functional analysis of FH variants of uncertain significance using Caenorhabditis elegans model
Suzanne Ferris1,2, Ivette M Menendez Perdomo1,2, Maja Tarailo-Graovac1,2
1Departments of Biochemistry, Molecular Biology and Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.
Purpose:
Variants of uncertain significance (VUS) in the essential metabolic gene fumarase (FH) have hampered diagnosis for patients with FH-associated diseases. Yet, early intervention is crucial for disease management, making the accurate and timely interpretation of VUS a clinical priority. Utilizing the multicellular model Caenorhabditis elegans (C. elegans), with a highly conserved fumarase ortholog (FUM-1), we aimed to facilitate functional analysis and interpretation of clinical FH variants.
Methods:
We used CRISPR-Cas9 techniques to generate C. elegans strains homozygous for FH variants reported in ClinVar and then assessed the effects on the animal's development.
Results:
C. elegans strains homozygous for a known benign variant did not show any visible phenotypes, whereas strains containing edited pathogenic variants could not survive. Assessment of 20 FH missense VUS revealed that majority (75%) did not display a visible phenotype under different conditions, whereas the rest affected viability and could therefore be reclassified as pathogenic.
Conclusion:
We showed that C. elegans could be reliably used for the reclassification of VUS in FH. Importantly, our proposed methodology based on the nematode's quick generation cycle, ease of strain creation, and phenotypic readouts opens the door for future studies on FH using C. elegans, including genotype-phenotype correlation and background effects.
