Semilobar Holoprosencephaly in a Neonate Born to a Mother with Gestational Diabetes Mellitus

Holoprosencephaly (HPE) is a rare congenital brain malformation characterized by incomplete separation of the cerebral hemispheres and often accompanied by craniofacial anomalies. Semilobar HPE represents an intermediate form with significant neurodevelopmental implications. We report a case of semilobar holoprosencephaly diagnosed antenatally in a term male neonate born to a 35-year-old woman with diet-controlled gestational diabetes mellitus (GDM). Prenatal ultrasound at 20 and 24 weeks revealed fused cerebral hemispheres, ventriculomegaly and bilateral cleft lip and palate. Despite counselling about the poor prognosis, the pregnancy was continued. The neonate presented with multiple dysmorphic features and profound neurological deficits and succumbed on day three of life. Parental refusal precluded genetic testing and postmortem examination. This case highlights the importance of early prenatal screening, strict maternal metabolic control and comprehensive parental counselling in pregnancies complicated by fetal anomalies. Genetic evaluation remains crucial for understanding ethology and guiding future family planning.