Prenatal Ultrasound Diagnosis of Binder Phenotype: Case Series of Seven Patients and Literature Review

<b>Background and Clinical Significance</b>: Binder syndrome or maxillonasal dysplasia is a rare developmental disorder affecting the anterior maxilla and nasal complex, characterized by midfacial hypoplasia, a flattened nasal bridge, and increased nasofrontal angle. <b>Case Presentation:</b> We present a case series of seven fetuses diagnosed with Binder phenotype through targeted ultrasound examination at our prenatal diagnosis center during the SARS-CoV-2 pandemic, between September 2021 and July 2023, including the first case described in the literature before 14 weeks. The median gestational age at diagnosis was 21 weeks. Ultrasound features included flattened fetal facial profile, increased nasofrontal angle (>143°), verticalized nasal bones and widened maxillary alveolar arch. Five cases presented as isolated anomalies, while two showed associated findings including growth restriction and polyhydramnios. Invasive prenatal diagnosis was offered in all cases, with three patients consenting to amniocentesis, all revealing normal karyotype and chromosomal microarray. Pregnancy outcomes varied: three patients opted for termination of pregnancy, one case resulted in intrauterine fetal demise, one delivered prematurely with confirmed postnatal phenotype, and two continued pregnancy with normal delivery. <b>Conclusions</b>: This relatively high case frequency within a short timeframe suggests that Binder syndrome, while rare, may not be as uncommon as previously reported. Accurate ultrasound diagnosis combined with comprehensive genetic counseling enables appropriate pregnancy management and optimal perinatal outcomes.