Rapid classification of a novel ALS-causing I149S variant in superoxide dismutase-1.

Amyotroph Lateral Scler Frontotemporal Degener

Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, Australia.

Published: August 2024

Variants of the oxygen free radical scavenging enzyme superoxide dismutase-1 (SOD1) are associated with the neurodegenerative disease amyotrophic lateral sclerosis (ALS). These variants occur in roughly 20% of familial ALS cases, and 1% of sporadic ALS cases. Here, we identified a novel SOD1 variant in a patient in their 50s who presented with movement deficiencies and neuropsychiatric features. The variant was heterozygous and resulted in the isoleucine at position 149 being substituted with a serine (I149S). analysis predicted the variant to be destabilizing to the SOD1 protein structure. Expression of the SOD1 variant with a C-terminal EGFP tag in neuronal-like NSC-34 cells resulted in extensive inclusion formation and reduced cell viability. Immunoblotting revealed that the intramolecular disulphide between Cys57 and Cys146 was fully reduced for SOD1. Furthermore, SOD1 was highly susceptible to proteolytic digestion, suggesting a large degree of instability to the protein fold. Finally, fluorescence correlation spectroscopy and native-PAGE of cell lysates showed that SOD1 was monomeric in solution in comparison to the dimeric SOD1. This experimental data was obtained within 3 months and resulted in the rapid re-classification of the variant from a variant of unknown significance (VUS) to a clinically actionable likely pathogenic variant.

Download full-text PDF

Source
http://dx.doi.org/10.1080/21678421.2024.2351177DOI Listing

Publication Analysis

Top Keywords

variant
8
superoxide dismutase-1
8
sod1
8
als cases
8
sod1 variant
8
rapid classification
4
classification novel
4
novel als-causing
4
als-causing i149s
4
i149s variant
4

Similar Publications

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!