Translational Neurogenetics Lab KAIST · Graduate School of Medical Science and Engineering

What we are interested in

Our laboratory investigates brain somatic mutations (mosaicism) as a major genetic cause of sporadic neurological disorders. The laboratory asks where somatic mutations originate, how they arise during brain development, and how they disrupt neural circuits to cause diseases of previously unknown etiology.

Epilepsy

We first showed that de novo somatic mutations in the PI3K–AKT3–mTOR pathway cause hemimegalencephaly (Lee et al., Nat Genet, 2012), and subsequently provided the first evidence that low-frequency somatic MTOR mutations arising from neural stem cells during development cause focal cortical dysplasia (FCD) type II with intractable epilepsy (Lim et al., Nat Med, 2015) — the most common surgically treated cause of childhood epilepsy — later extending the mutational spectrum to TSC1/TSC2 (Lim et al., Am J Hum Genet, 2017) and SLC35A2 (Sim et al., Neurol Genet, 2018). By developing methods for precise detection of ultra-low-level variants, we resolved the genetic cause in up to 80% of FCD type II cases (Sim et al., Acta Neuropathol, 2019; Kim et al., Ann Neurol, 2023), and defined the threshold of mosaicism sufficient to produce focal seizures (Kim et al., Brain, 2024). Mechanistically, we showed that MTOR mosaicism disrupts neuronal ciliogenesis to cause cortical dyslamination (Park et al., Neuron, 2018), and drives epileptogenesis through non-cell-autonomous mechanisms (Kim et al., Ann Neurol, 2021). These findings were incorporated into the revised ILAE classification and diagnostic criteria for FCD, for which the PI served on the ILAE Task Force.

Brain Tumors

we mapped the cellular origins of the precancer-to-cancer transition in the human brain: BRAF V600E arising in radial glial cells underlies epilepsy-associated pediatric tumors (Koh et al., Nat Med, 2018); subventricular zone (SVZ) astrocyte-like neural stem cells carrying low-level driver mutations give rise to glioblastoma at distant sites (Lee et al., Nature, 2018) and serve as a reservoir for post-surgical recurrence (Li et al., Mol Cancer, 2025); precancerous cells initiate glioblastoma evolution and generate intratumoral heterogeneity (Kim et al., Cancer Discov, 2025); and IDH-mutant gliomas arise from glial progenitor cells rather than neural stem cells (Park et al., Science, 2026).

Neurodegenerative Diseases

We have extended our framework to neurodegenerative disorders such as Alzheimer’s disease (Park et al., Nat Commun, 2019), Amyotrophic Lateral Sclerosis (ALS) as well as other neuropsychiatric disorders (Kim et al., Mol Psychiatry, 2022; Kim et al., Exp Mol Med, 2024).

Our workflow

Our ongoing work addresses a question that follows directly from these discoveries: mutations alone do not make disease. Because even healthy brains harbor small numbers of mutant cells, we ask which mosaic ecosystems actually transition to disease, and when and how that transition can be stopped. We are therefore reframing disease initiation as a threshold-crossing event determined by the interaction of cell of origin, microenvironment, and time — in which mutant cell populations, under various biological stress, progressively perturb surrounding cells and neural networks until cell states shift toward changes that are difficult to reverse.

Our strategy proceeds in four stages: (i) mapping the seeds by combining single-cell and spatial omics with ultra-rare variant detection; (ii) decoding transition mechanisms to identify the key regulators linking mutant cells, their ecosystem, and biological stress, including how mutant cells perturb surrounding neurons and neural network function (iii) building therapeutic platforms — ASO, siRNA, AAV, and epigenome editors — designed to control pathological state transitions rather than merely correct the underlying mutation; and (iv) advancing predictive and preventive medicine through cerebrospinal fluid biomarkers and AI-based risk prediction that enable intervention before clinical onset. This program is pursued together with Sovargen, a biotechnology company co-founded on the KAIST campus, and builds on our framework for RNA therapeutics targeting brain somatic mutations