Mono and biallelic variants in<i>HCN2</i>cause severe neurodevelopmental disorders

Abstract Hyperpolarization activated Cyclic Nucleotide (HCN) gated channels are crucial for various neurophysiological functions, including learning and sensory functions, and their dysfunction are responsible for brain disorders, such as epilepsy. To date,HCN2variants have only been associated with mild epilepsy and recently, one monoallelic missense variant has been linked to developmental and epileptic encephalopathy. Here, we expand the phenotypic spectrum ofHCN2-related disorders by describing twenty-one additional individuals from fifteen unrelated families carryingHCN2variants. Seventeen individuals had developmental delay/intellectual disability (DD/ID), two had borderline DD/ID, and one had borderline DD. Ten individuals had epilepsy with DD/ID, with median age of onset of 10 months, and one had epilepsy with normal development. Molecular diagnosis identified thirteen different pathogenicHCN2variants, including eleven missense variants affecting highly conserved amino acids, one frameshift variant, and one in-frame deletion. Seven variants were monoallelic of which five occurredde novo,one was not maternally inherited, one was inherited from a father with mild learning disabilities, and one was of unknown inheritance. The remaining six variants were biallelic, with four homozygous and two compound heterozygous variants. Functional studies using two-electrode voltage-clamp recordings inXenopus laevisoocytes were performed on three monoallelic variants, p.(Arg324His), p.(Ala363Val), and p.(Met374Leu), and three biallelic variants, p.(Leu377His), p.(Pro493Leu) and p.(Gly587Asp). The p.(Arg324His) variant induced a strong increase of HCN2 conductance, while p.(Ala363Val) and p.(Met374Leu) displayed dominant negative effects, leading to a partial loss of HCN2 channel function. By confocal imaging, we found that the p.(Leu377His), p.(Pro493Leu) and p.(Gly587Asp) pathogenic variants impaired membrane trafficking, resulting in a complete loss of HCN2 elicited currents inXenopusoocytes. Structural 3D-analysis in depolarized and hyperpolarized states of HCN2 channels, revealed that the pathogenic variants p.(His205Gln), p.(Ser409Leu), p.(Arg324Cys), p.(Asn369Ser) and p.(Gly460Asp) modify molecular interactions altering HCN2 function. Taken together, our data broadens the clinical spectrum associated withHCN2variants, and disclose thatHCN2is involved in developmental encephalopathy with or without epilepsy..

Medienart:

Preprint

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

bioRxiv.org - (2024) vom: 25. März Zur Gesamtaufnahme - year:2024

Sprache:

Englisch

Beteiligte Personen:

Houdayer, Clara [VerfasserIn]
Phillips, A Marie [VerfasserIn]
Chabbert, Marie [VerfasserIn]
Bourreau, Jennifer [VerfasserIn]
Maroofian, Reza [VerfasserIn]
Houlden, Henry [VerfasserIn]
Richards, Kay [VerfasserIn]
Saadi, Nebal Waill [VerfasserIn]
Dad’ová, Eliška [VerfasserIn]
Van Bogaert, Patrick [VerfasserIn]
Rupin, Mailys [VerfasserIn]
Keren, Boris [VerfasserIn]
Charles, Perrine [VerfasserIn]
Smol, Thomas [VerfasserIn]
Riquet, Audrey [VerfasserIn]
Pais, Lynn [VerfasserIn]
O’Donnell-Luria, Anne [VerfasserIn]
VanNoy, Grace E. [VerfasserIn]
Bayat, Allan [VerfasserIn]
Møller, Rikke S [VerfasserIn]
Olofsson, Kern [VerfasserIn]
Abou Jamra, Rami [VerfasserIn]
Syrbe, Steffen [VerfasserIn]
Dasouki, Majed [VerfasserIn]
Seaver, Laurie H [VerfasserIn]
Sullivan, Jennifer A [VerfasserIn]
Shashi, Vandana [VerfasserIn]
Alkuraya, Fowzan S [VerfasserIn]
Poss, Alexis F [VerfasserIn]
Spence, J Edward [VerfasserIn]
Schnur, Rhonda E [VerfasserIn]
Forster, Ian C [VerfasserIn]
Mckenzie, Chaseley E [VerfasserIn]
Simons, Cas [VerfasserIn]
Wang, Min [VerfasserIn]
Snell, Penny [VerfasserIn]
Kothur, Kavitha [VerfasserIn]
Buckley, Michael [VerfasserIn]
Roscioli, Tony [VerfasserIn]
Elserafy, Noha [VerfasserIn]
Dauriat, Benjamin [VerfasserIn]
Procaccio, Vincent [VerfasserIn]
Henrion, Daniel [VerfasserIn]
Lenaers, Guy [VerfasserIn]
Colin, Estelle [VerfasserIn]
Verbeek, Nienke E. [VerfasserIn]
Van Gassen, Koen L. [VerfasserIn]
Legendre, Claire [VerfasserIn]
Bonneau, Dominique [VerfasserIn]
Reid, Christopher A [VerfasserIn]
Howell, Katherine B [VerfasserIn]
Ziegler, Alban [VerfasserIn]
Legros, Christian [VerfasserIn]

Links:

Volltext [kostenfrei]

Themen:

570
Biology

doi:

10.1101/2024.03.19.24303984

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

XBI043009727