ALPK3 Cardiomyopathy: Integrative Review With Systematic Variant Curation, Mechanisms, and Translation

Pathogenic variants in ALPK3 (α-protein kinase 3), an atypical α‑kinase acting as a sarcomeric M-band scaffold, cause cardiomyopathy with severity linked to zygosity. We present a comprehensive review with systematic curation of peer-reviewed clinical and experimental reports through June 9, 2025, encompassing 156 patient-level variants and all published preclinical models. Biallelic loss-of-function variants lead to severe, often lethal cardiomyopathy with prenatal or early onset presentation and extracardiac involvement. Heterozygous protein-truncating variants, defined as nonsense or frameshift (resulting from insertion/deletion events or splicing mutations), explain ≈1% to 4% of adult hypertrophic cardiomyopathy, often with apical/septal hypertrophy, right ventricular involvement, fibrosis, and risk of progression. ALPK3 lacks catalytic activity and maintains sarcomeric proteostasis by scaffolding MYOMs (myomesins), MuRF (muscle ring-finger protein) E3 ligases, and SQSTM1 (sequestosome-1)/p62. Loss of this scaffolding function displaces MYOMs, drives thick‑filament protein aggregation, and precipitates severe contractile dysfunction in human induced pluripotent stem cell–derived cardiomyocytes and multiple mouse models. Therapeutic proof‑of‑concept has now been achieved on 2 fronts: (1) pharmacological correction of sarcomeric hypercontractility with the myosin inhibitor mavacamten and (2) durable phenotypic rescue in global knockout mice using an adeno-associated virus–delivered miniALPK3 gene‑replacement construct. Together, these data position ALPK3 cardiomyopathy as a compelling target for precision medicine. Early genetic diagnosis, genotype-tailored surveillance, and focused development of gene-replacement or editing strategies, potentially combined with modulators of the ALPK3-MuRF proteostatic axis, offer a realistic path to disease-modifying therapy for this once enigmatic condition.