Clinical Features and Gene Mutation of Neonatal Seizures

Background: Early-stage seizures caused by an undetermined etiology cannot be treated with effective antiepileptic drugs in a timely manner, leading to poor seizure control and severely affecting long-term prognosis. Therefore, early clarification of the cause and targeted timely treatment are crucial. Objective: To characterize the clinical features and genetic mutations in neonatal seizures, particularly those of unknown cause. Methods: Clinical data from 56 neonates with seizures were retrospectively analyzed. Family-based whole-exome sequencing was performed in six cases of undetermined etiology. The KCNQ2 variant was classified according to the ACMG guidelines. Basic statistical comparisons were performed using the chi-square test. Results: Hypoxic-ischemic encephalopathy (HIE) was the most common cause (23.21%, 13/56), with most seizures occurring within the first three days of life. Subtle seizures were the predominant type (46.42%, 26/56). Abnormal amplitude-integrated EEG findings were observed in 58.82% (30/51). The HIE group had a significantly higher proportion of seizures occurring within the first three days of life compared to the non-HIE group (p = 0.01). A novel heterozygous KCNQ2 mutation (c.766G>T, p.Gly256Trp) was identified and classified as likely pathogenic according to the ACMG guidelines. Conclusions: HIE remains a leading cause of early-onset neonatal seizures. A novel likely pathogenic KCNQ2 mutation expands the genetic spectrum of neonatal seizures, highlighting the value of genetic testing.