ANK2 loss-of-function variants are associated with epilepsy, and lead to impaired axon initial segment plasticity and hyperactive network activity in hiPSC-derived neuronal networks.

Human molecular genetics 2023 Jul 04

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To characterize a novel neurodevelopmental syndrome due to loss-of-function (LoF) variants in Ankyrin 2 (ANK2), and to explore the effects on neuronal network dynamics and homeostatic plasticity in human-induced pluripotent stem cell-derived neurons. We collected clinical and molecular data of 12 individuals with heterozygous de novo LoF variants in ANK2. We generated a heterozygous LoF allele of ANK2 using CRISPR/Cas9 in human-induced pluripotent stem cells (hiPSCs). HiPSCs were differentiated into excitatory neurons, and we measured their spontaneous electrophysiological responses using micro-electrode arrays (MEAs). We also characterized their somatodendritic morphology and axon initial segment (AIS) structure and plasticity. We found a broad neurodevelopmental disorder (NDD), comprising intellectual disability, autism spectrum disorders and early onset epilepsy. Using MEAs, we found that hiPSC-derived neurons with heterozygous LoF of ANK2 show a hyperactive and desynchronized neuronal network. ANK2-deficient neurons also showed increased somatodendritic structures and altered AIS structure of which its plasticity is impaired upon activity-dependent modulation. Phenotypic characterization of patients with de novo ANK2 LoF variants defines a novel NDD with early onset epilepsy. Our functional in vitro data of ANK2-deficient human neurons show a specific neuronal phenotype in which reduced ANKB expression leads to hyperactive and desynchronized neuronal network activity, increased somatodendritic complexity and AIS structure and impaired activity-dependent plasticity of the AIS. © The Author(s) 2023. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Citation

Maria W A Teunissen, Elly Lewerissa, Eline J H van Hugte, Shan Wang, Charlotte W Ockeloen, David A Koolen, Rolph Pfundt, Carlo L M Marcelis, Eva Brilstra, Jennifer L Howe, Stephen W Scherer, Xavier Le Guillou, Frédéric Bilan, Michelle Primiano, Jasmin Roohi, Amelie Piton, Anne de Saint Martin, Sarah Baer, Simone Seiffert, Konrad Platzer, Rami Abou Jamra, Steffen Syrbe, Jan H Doering, Shenela Lakhani, Srishti Nangia, Christian Gilissen, R Jeroen Vermeulen, Rob P W Rouhl, Han G Brunner, Marjolein H Willemsen, Nael Nadif Kasri. ANK2 loss-of-function variants are associated with epilepsy, and lead to impaired axon initial segment plasticity and hyperactive network activity in hiPSC-derived neuronal networks. Human molecular genetics. 2023 Jul 04;32(14):2373-2385