Beyond the usual suspects: neonatal presentation of Prader-Willi syndrome

Prader-Willi syndrome (PWS) is a rare genetic disorder characterised by neonatal hypotonia, feeding difficulties and hypogonadism. Early diagnosis is crucial but often delayed, as initial features may mimic birth asphyxia or sepsis, especially in resource-limited settings. We report a term male infant, small for gestational age, who presented with respiratory distress, stupor and hypotonia. Birth asphyxia and sepsis were excluded based on normal cord gases, a negative sepsis screen and the clinical course. Thyroid function and cranial ultrasound were normal. Antenatal polyhydramnios and growth restriction, along with persistent hypotonia, poor suck and bilateral cryptorchidism, raised early suspicion of PWS. On day 5, worsening respiratory effort prompted a meningitis workup, which was negative. Methylation-specific multiplex ligation-dependent probe amplification (MLPA) confirmed a fully methylated MAGEL2/SNRPN region without 15q11.2-q13 deletion or duplication. In neonates with persistent hypotonia and hypogonadism, early genetic testing should be considered. MLPA enables definitive diagnosis of PWS in the neonatal period and guides early intervention.