Objective:To explore the genetic etiology for a child with Progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal dominant 6 (PEOA6).Methods:A child who had attended the Women and Children′s Hospital Affiliated to Ningbo University on 7 August, 2023 was selected as the study subject. Clinical data of the child were analyzed retrospectively. The child and her parents were subjected to whole exome sequencing (WES), and candidate variant was verified by Sanger sequencing and bioinformatic analysis. This study was approved by Medical Ethics Committee of the Women and Children′s Hospital Affiliated to Ningbo University (Ethics No. EC2020-048).Results:The child, a 7-year-old female, had presented with limb muscle pain, amyosthenia, significantly increased creatine kinase, congenital diaphragmatic hernia and recurrent respiratory tract infections. WES revealed that she has harbored a heterozygous c. 1590G>C (p.L530F) variant of the DNA2 gene, which was verified to have a de novo origin by Sanger sequencing. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the c.1590G>C was rated as a likely pathogenic variant (PS2+ PM2_Supporting+ PP3). Conclusion:The c.1590G>C (p.L530F) variant of the DNA2 gene probably underlay the PEOA6 in this child.