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Updated: Jan 31, 2026

Anteromesial Temporal Lobectomy for Medically Intractable Temporal Lobe Epilepsy: An Operative Study
Published on: August 15, 2025
Brain somatic mutations in SLC35A2 cause intractable epilepsy with aberrant N-glycosylation
Nam Suk Sim1, Youngsuk Seo1, Jae Seok Lim1
1Graduate School of Medical Science and Engineering (N.S.S., J.S.L., W.K.K., J.H.L.), KAIST; Asia Glycomics Reference Site (Y.S., H.J.A.); Graduate School of Analytical Science & Technology (Y.S., H.J.A.), Chungnam National University, Daejeon, Korea; Department of Biomedical System informatics (H.S., S.K.), Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine; Division of Pediatric Neurology (H.D.K., H.C.K.), Department of Pediatrics, Pediatric Epilepsy Clinics, Severance Children's Hospital; Epilepsy Research Institute (H.D.K., H.C.K.), Yonsei University College of Medicine; Department of Pathology (S.H.K.), Yonsei University College of Medicine, Seoul, Korea; and Pediatric Neurosurgery (D.S.K.), Severance Children's Hospital, Department of Neurosurgery, Yonsei University College of Medicine, Seoul, South Korea.
Objective:
To identify whether somatic mutations in SLC35A2 alter N-glycan structures in human brain tissues and cause nonlesional focal epilepsy (NLFE) or mild malformation of cortical development (mMCD).
Methods:
Deep whole exome and targeted sequencing analyses were conducted for matched brain and blood tissues from patients with intractable NLFE and patients with mMCD who are negative for mutations in mTOR pathway genes. Furthermore, tissue glyco-capture and nanoLC/mass spectrometry analysis were performed to examine N-glycosylation in affected brain tissue.
Results:
Six of the 31 (19.3%) study patients exhibited brain-only mutations in SLC35A2 (mostly nonsense and splicing site mutations) encoding a uridine diphosphate (UDP)-galactose transporter. Glycome analysis revealed the presence of an aberrant N-glycan series, including high degrees of N-acetylglucosamine, in brain tissues with SLC35A2 mutations.
Conclusion:
Our study suggests that brain somatic mutations in SLC35A2 cause intractable focal epilepsy with NLFE or mMCD via aberrant N-glycosylation in the affected brain.
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