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Objective: Epilepsy, a prevalent neurological disorder, has multifaceted etiologies. Next-generation sequencing (NGS) has emerged as a robust diagnostic tool for this condition. This study aims to evaluate the detection efficiencies of different exome-based sequencing techniques. Methods: Exome-based epilepsy panel tests, clinical exome sequencing (CES), and whole exome sequencing (WES) were conducted on 259 pediatric patients diagnosed with epilepsy. Single-nucleotide variants (SNVs) and copy number variants (CNVs) were interpreted based on each patient's phenotypic presentation. Additionally, data concerning clinical symptoms, neuroimaging findings, treatment responses, and prognostic outcomes were collected and analyzed. Results: The overall diagnostic yield was 32.8% (85/259), with a diagnostic yield of 40.0% for exome-based epilepsy panels, 30.1% for CES, and 27.8% for WES. We identified 82 cases with pathogenic or likely pathogenic SNVs and 4 cases with pathogenic CNVs, of which one case with both SNV and CNV. The most frequently detected gene was PRRT2, present in 10.0% (9/82) of cases. Epileptic syndromes were diagnosed in 66 patients, predominantly West Syndrome, Dravet Syndrome and Genetic Epilepsy with Febrile Seizures plus. Conclusion: NGS is an effective method for uncovering the genetic foundations of pediatric epilepsy, with diagnostic yields varying based on the sequencing approach used. The growing preference for WES underscores its utility in complex cases, pointing to a trend towards more tailored diagnostic strategies. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to evaluate the yield and applicability of expanded carrier screening and propose carrier rate screening thresholds suitable for the Chinese population by comparing the current screening panel with the American College of Medical Genetics and Genomics recommended panel of 113 genes. Methods: Using targeted next‐generation sequencing, a customized panel with 334 genes was performed on 2168 individuals without clinical phenotypes for expanded carrier screening purpose. Variant interpretation followed the American College of Medical Genetics and Genomics guidelines. Carrier rates were calculated for each identified variant and each gene. At‐risk couple rates were also assessed. The yield of expanded carrier screening was evaluated through calculating cumulative carrier rate. Results: Overall, 65.87% of the individuals were found to be carriers of at least 1 disease causing variants. The overall at‐risk couple rate was 11.76%, of which the GJB2:c.109G > A related at‐risk couple rate was 5.78%. The cumulative carrier rate of 334‐panel was 65.53%. When screened genes with gene carrier rate ≥1/1000, the expanded carrier screening can cover over 90% of the cumulative carrier rate and at‐risk couples. A total of 86 genes overlapped with American College of Medical Genetics and Genomics Tier‐3 genes and were attributed to the cumulative carrier rate of 47.33%. Conclusion: Expanded carrier screening using the 334‐gene panel showed high screening efficiency. A threshold of gene carrier rate ≥1/1000 is recommended for selecting carrier screening genes in the Chinese Han population. This study highlights the importance of customizing screening panels based on the ACMG Tier‐3 genes in conjunction with population‐specific carrier frequencies to improve the accuracy and effectiveness of expanded carrier screening. Key points: What is already known about this topic?Expanded carrier screening can effectively identify carriers in the general population and reduce the occurrence of genetic disorders. Nevertheless, the inclusion scope of screened diseases and the number of genes for a specific ethnic population has been a topic of ongoing debate. What does this study add?This study conducted carrier screening method development with the data from individuals from the general population and identified genes with high carrier frequencies in the Chinese population.The study highlights the importance of customizing screening panels based on population‐specific carrier frequencies to improve ECS utility. [ABSTRACT FROM AUTHOR]

Background: Progressive external ophthalmoplegia (PEO) is a common subtype of mitochondrial encephalomyopathy. Objective: The study aimed to investigate the relationship between mitochondrial DNA (mtDNA) abnormalities, muscle pathology, and clinical manifestations in Chinese patients with single large‐scale mtDNA deletion presenting with PEO. Methods: This is a retrospective single‐center study. Patients with PEO who had a single large deletion in mitochondrial DNA were included in this study. The associations were analyzed between mtDNA deletion patterns, myopathological changes, and clinical characteristics. Results: In total, 155 patients with mitochondrial PEO carrying single large‐scale mtDNA mutations were enrolled, including 137 chronic progressive external ophthalmoplegia (CPEO) and 18 Kearns–Sayre syndrome (KSS) patients. The onset ages were 9.61 ± 4.12 in KSS and 20.15 ± 9.06 in CPEO. The mtDNA deletions ranged from 2225 bp to 9131 bp, with m.8470_13446del being the most common. The KSS group showed longer deletions than the CPEO group (p = 0.004). Additionally, a higher number of deleted genes encoding respiratory chain complex subunits (p = 0.001) and tRNA genes (p = 0.009) were also observed in the KSS group. A weak negative correlation between the mtDNA deletion size and ages of onset (p < 0.001, r = −0.369) was observed. The proportion of ragged red fibers, ragged blue fibers, and cytochrome c negative fibers did not correlate significantly with onset ages (p > 0.05). However, a higher percentage of abnormal muscle fibers corresponds to an increased prevalence of exercise intolerance, limb muscle weakness, dysphagia, and cerebellar ataxia. Conclusion: We reported a large Chinese cohort consisting of mitochondrial PEO patients with single large‐scale mtDNA deletions. Our results demonstrated that the length and locations of mtDNA deletions may influence onset ages and clinical phenotypes. The severity of muscle pathology could not only indicate diagnosis but also may be associated with clinical manifestations beyond the extraocular muscles. [ABSTRACT FROM AUTHOR]