1. Expanding the clinical and genetic spectrum of ALPK3 variants: Phenotypes identified in pediatric cardiomyopathy patients and adults with heterozygous variants.
- Author
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Herkert JC, Verhagen JMA, Yotti R, Haghighi A, Phelan DG, James PA, Brown NJ, Stutterd C, Macciocca I, Leong K, Bulthuis MLC, van Bever Y, van Slegtenhorst MA, Boven LG, Roberts AE, Agarwal R, Seidman J, Lakdawala NK, Fernández-Avilés F, Burke MA, Pierpont ME, Braunlin E, Ḉağlayan AO, Barge-Schaapveld DQCM, Birnie E, van Osch-Gevers L, van Langen IM, Jongbloed JDH, Lockhart PJ, Amor DJ, Seidman CE, and van de Laar IMBH
- Subjects
- Abnormalities, Multiple genetics, Adult, Age of Onset, Cardiomyopathies diagnostic imaging, Cardiomyopathies physiopathology, Cardiomyopathy, Dilated genetics, Cardiomyopathy, Hypertrophic genetics, Child, Child, Preschool, Chromosomes, Human, Pair 15 genetics, Echocardiography, Electrocardiography, Humans, Infant, Phenotype, Cardiomyopathies genetics, Heterozygote, Loss of Function Mutation, Muscle Proteins genetics, Mutation, Missense, Protein Kinases genetics
- Abstract
Introduction: Biallelic damaging variants in ALPK3, encoding alpha-protein kinase 3, cause pediatric-onset cardiomyopathy with manifestations that are incompletely defined., Methods and Results: We analyzed clinical manifestations of damaging biallelic ALPK3 variants in 19 pediatric patients, including nine previously published cases. Among these, 11 loss-of-function (LoF) variants, seven compound LoF and deleterious missense variants, and one homozygous deleterious missense variant were identified. Among 18 live-born patients, 8 exhibited neonatal dilated cardiomyopathy (44.4%; 95% CI: 21.5%-69.2%) that subsequently transitioned into ventricular hypertrophy. The majority of patients had extracardiac phenotypes, including contractures, scoliosis, cleft palate, and facial dysmorphisms. We observed no association between variant type or location, disease severity, and/or extracardiac manifestations. Myocardial histopathology showed focal cardiomyocyte hypertrophy, subendocardial fibroelastosis in patients under 4 years of age, and myofibrillar disarray in adults. Rare heterozygous ALPK3 variants were also assessed in adult-onset cardiomyopathy patients. Among 1548 Dutch patients referred for initial genetic analyses, we identified 39 individuals with rare heterozygous ALPK3 variants (2.5%; 95% CI: 1.8%-3.4%), including 26 missense and 10 LoF variants. Among 149 U.S. patients without pathogenic variants in 83 cardiomyopathy-related genes, we identified six missense and nine LoF ALPK3 variants (10.1%; 95% CI: 5.7%-16.1%). LoF ALPK3 variants were increased in comparison to matched controls (Dutch cohort, P = 1.6×10
-5 ; U.S. cohort, P = 2.2×10-13 )., Conclusion: Biallelic damaging ALPK3 variants cause pediatric cardiomyopathy manifested by DCM transitioning to hypertrophy, often with poor contractile function. Additional extracardiac features occur in most patients, including musculoskeletal abnormalities and cleft palate. Heterozygous LoF ALPK3 variants are enriched in adults with cardiomyopathy and may contribute to their cardiomyopathy. Adults with ALPK3 LoF variants therefore warrant evaluations for cardiomyopathy., (Copyright © 2020 The Author(s). Published by Elsevier Inc. All rights reserved.)- Published
- 2020
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