A Novel GNAO1 Missense Variant Associated with Ealy-Onset Epileptic Encephalopathy

Abstract

Background: GNAO1 encodes the Gαo protein, a critical mediator of GPCR signaling in the nervous system. Mutations in GNAO1 cause early-onset epileptic encephalopathy and movement disorders. This study characterized a novel missense variant, GNAO1 E20K (c.58G>A), using comprehensive in silico approaches.

Methods: The variant was identified from gnomAD and analyzed using MutationTaster, BioEdit, and STRING for pathogenicity prediction, sequence alignment, and protein-protein interaction mapping. Molecular docking with N-acetylglucosamine (NAG) compared binding affinities between wild-type and mutant GNAO1.

Results: The E20K variant was absent from population databases and affected a highly conserved glutamic acid residue (PhyloP: 9.527; PhastCons: 1.0). GNAO1 showed extreme constraint (LOEUF: 0.10; missense oe: 0.35). MutationTaster classified the variant as deleterious (97% damaging). STRING analysis revealed high-confidence interactions with GNB1 (0.996), RGS16 (0.993), DRD2 (0.950), and ADRA2A (0.956). Comparative docking demonstrated reduced NAG binding affinity in the mutant (−5.5913 kcal/mol) versus wild-type (−5.8479 kcal/mol), with altered hydrogen bonding patterns and a strengthened Lys46 interaction (−5.5 kcal/mol) in the mutant.

Conclusions: The GNAO1 E20K variant exhibits multiple lines of in silico evidence supporting pathogenicity, including extreme evolutionary conservation, population rarity, high gene constraint, and altered ligand binding. Functional validation and clinical evaluation are warranted.