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Objective: To explore the clinical and genetic characteristics of a child with Arrhythmogenic right ventricular cardiomyopathy (ARVC)., Methods: A 6-year-old boy with ARVC who had visited Fujian Provincial Children's Hospital on August 23, 2022 was selected as the study subject. Relevant clinical data were collected, and peripheral venous blood samples were collected from the child and his parents for genetic testing through whole exome sequencing (WES). Sanger sequencing was carried out for family verification, and pathogenicity analysis was conducted for the candidate variants., Results: The child had exhibited clinical symptoms including systemic edema, generalized heart enlargement, universal reduction of interventricular septum and ventricular wall movement, reduced left ventricular diastolic and systolic function, and reduced right ventricular systolic function. WES revealed that the child has harbored compound heterozygous variants of the PKP2 gene, namely c.119_122del (p.Leu40ArgfsTer71) and c.1978G>A (p.Gly660Arg), which were verified by Sanger sequencing to be respectively inherited from his father and mother. The c.119_122del variant has not been recorded in the 1000 Genomes, gnomAD and ExAC databases, and was predicted to lead to truncation of the PKP2 protein by SWISS-MODEL and PyMOL online software and classified as likely pathogenic based on the guidelines jointly developed by the American College of Medical Genetics and Genomics (ACMG) and ClinGen. The c.1978G>A variant has also not been recorded in the 1000 Genomes, gnomAD and ExAC databases, and was predicted to be deleterious by online software including REVEL, SIFT, CADD, Mutation Taster, and PolyPhen-2. The amino acid encoded by the variant site was highly conserved among various species by analysis using T-coffee and ESPript v3.0 online servers. The variant may affect the protein function by SWISS-MODEL and PyMOL online server analysis, and was classified as likely pathogenic based on the guidelines jointly developed by the ACMG and ClinGen., Conclusion: The compound heterozygous variants of c.119_122del (p.Leu40ArgfsTer71) and c.1978G>A (p.Gly660Arg) of the PKP2 gene probably underlay the ARVC in this child. Above finding has broadened the spectrum of PKP2 gene variants and provided a reference for the diagnosis and genetic counseling.

Objective: The purpose of this study was to screen genetic variations in plakophilin-2 (PKP2) gene in patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) and investigate the differences in clinical features between mutation and no-mutation groups., Methods: Thirty unrelated Chinese patients clinically diagnosed with ARVC/D and 50 healthy controls were included. Genomic DNA was isolated from peripheral blood samples. PCR and direct sequencing were used to detect variations in PKP2 gene., Results: Eight PKP2 mutant variants were identified in 10 ARVC/D patients (8 men, 2 women). Among the eight mutation, three (c.2194C>T, c. 1170+ 1G>A and c. 810_813delGGTC) were novel mutation. Clinical features of the PKP2 mutation group were similar to those of the non-mutation group., Conclusions: The rate of PKP2 mutation is 33.3% (10/30) in ARVC/D patients. The penetrance of PKP2 mutation for ARVC/D tends to be higher in man patients. No significant differences could be detected in phenotype characteristics between patients with and without PKP2 mutation.