Prenatal diagnosis of Apert syndrome caused by a de novo FGFR2 mutation in the second trimester: a case report

BACKGROUND: Apert syndrome is a syndromic craniosynostosis primarily caused by pathogenic mutations in the fibroblast growth factor receptor 2 (FGFR2) gene. Current prenatal diagnosis of Apert syndrome predominantly relies on ultrasound imaging in the third trimester (28 weeks of gestation to delivery), which is not conducive to early clinical decision-making. CASE PRESENTATION: In this case, prenatal ultrasound at the 20 weeks of gestation revealed craniosynostosis, oligohydramnios, and syndactyly of hands and feet in the fetus. Whole-exome sequencing (WES) followed by Sanger sequencing was performed on the affected fetus and its parents. A de novo pathogenic mutation in the FGFR2 gene was identified. Based on the fetal ultrasound findings and genetic test results, Apert syndrome was diagnosed as early as the 20 weeks of gestation (second trimester). CONCLUSIONS: The combination of prenatal ultrasound and WES enables the diagnosis of Apert syndrome in the second trimester, providing valuable support for early prenatal counseling and pregnancy management.