Summary
Alternating hemiplegia of childhood (AHC) is a neurodevelopmental disorder with no disease-modifying treatment. Mutations in ATP1A3, encoding an Na/K ATPase subunit, cause 70% of AHC cases. Here, we present prime editing (PE) and base editing (BE) strategies to correct ATP1A3 and Atp1a3 mutations in human cells and in two AHC mouse models. We used PE and BE to correct five prevalent ATP1A3 mutations with 43%–90% efficiency. AAV9-mediated in vivo PE corrects Atp1a3 D801N and E815K in the CNS of two AHC mouse models, yielding up to 48% DNA correction and 73% mRNA correction in bulk brain cortex. In vivo PE rescued clinically relevant phenotypes, including restoration of ATPase activity; amelioration of paroxysmal spells, motor defects, and cognition deficits; and dramatic extension of animal lifespan. This work suggests a potential one-time PE treatment for AHC and establishes the ability of PE to rescue a neurological disease in animals.++
Introduction
Alternating hemiplegia of childhood (AHC) is a neurodevelopmental disorder that presents within the first 18 months of life with recurrent paroxysmal attacks that include hemiplegia (paralysis affecting one side of the body), dystonia (painful involuntary muscle contractions), abnormal eye movements, and seizures. Patients with AHC also exhibit non-paroxysmal hypotonia (low muscle tone), developmental delay, and intellectual disability.1 AHC is exceptionally rare, with an estimated incidence of 1 in 1,000,000 individuals.2 No disease-modifying treatments for AHC exist.1
Approximately 70% of AHC cases are associated with pathogenic variants in ATP1A3, which encodes the catalytic α3 subunit of the neuronal Na/K ATPase protein complex.++3,4,5,6 Although more than 50 AHC-associated ATP1A3 pathogenic variants have been reported,7 three—D801N, E815K, and G947R—account for more than 65% of ATP1A3-associated AHC cases, with approximate prevalences of 40%, 20%, and 10%, respectively3,4,5,6,8,9,10,11,12 (Figure 1A). Pathogenic ATP1A3 variants are heterozygous, missense, and almost always de novo, with a notable absence of overt loss-of-function variants such as frameshifts or premature stop codons.3,4,5,8,9,10,11,12 Electrophysiological studies suggest that the D801N, E815K, and G947R mutants impair wild-type ATP1A3 activity.13 In mice, homozygosity for patient-derived pathogenic variants or complete Atp1a3 knockout is lethal.14,15,16 Heterozygous Atp1a3+/− knockout mice do not develop severe phenotypic defects in contrast to mice heterozygous for D801N, E815K, and G947R mutations.14,15,16,17,18,19,20,21,22,23 Although these observations support a dominant-negative disease mechanism for AHC-associated ATP1A3 mutations, the absence of a definitive molecular mechanism1,14,24,25 and the challenge of selectively targeting dominant-negative protein variants hinders the development of conventional, non-genetic therapies. The current standard-of-care focuses on symptom management.1
Link to the paper：https://www.cell.com/cell/fulltext/S0092-8674(25)00740-8
