Trisomy 18 presenting with complete bilateral radial aplasia: a rare case report

BACKGROUND: Trisomy 18 (Edwards syndrome) is the second most common autosomal trisomy and is associated with severe multisystem congenital anomalies and high neonatal mortality. Typical limb findings include clenched fists with overlapping fingers; however, radial ray defects are also recognized within its phenotypic spectrum. CASE PRESENTATION: We report a preterm male infant born at 33 + 6 weeks' gestation who presented with severe respiratory distress, complex congenital heart disease, profound symmetrical growth restriction, and complete bilateral radial aplasia with absent thumbs. Antenatal ultrasonography had demonstrated intrauterine growth restriction, congenital heart disease, and upper limb anomalies, raising suspicion of an underlying syndromic condition. Postnatal peripheral blood karyotyping, sent within the first days of life, confirmed a uniform 47, XY, + 18 karyotype. The infant required prolonged mechanical ventilation and intensive supportive care but remained ventilator dependent. Despite ongoing management, he developed progressive cardiorespiratory failure and died at 61 days of life. CONCLUSION: This case highlights a severe expression of radial ray involvement within the phenotypic spectrum of Trisomy 18 and underscores the importance of comprehensive prenatal evaluation, cytogenetic confirmation, and careful multidisciplinary counseling when significant limb reduction defects are identified.