Agenesis of septum pellucidum

  • Not a severe malformation
  • Often an indicator of other malformations – septo-optic dysplasia, holoprosencephaly, Chiari II malformation, schizencephaly, other migration disorders
  •  <1% associated with HESX1 gene mutation
  • Absence of septum pellucidum
  • Box-like configuration of frontal horns
  • Small optic nerves and chiasm
  • Small anterior pituitary gland
  • Ectopic bright spot of posterior pituitary
  • Look for associated malformations: callosal agenesis, holoprosencephaly, cobblestone cortical malformations, bilateral polymicrogyria
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Sarwar, Mohammad. “The septum pellucidum: normal and abnormal.” American Journal of Neuroradiology 10.5 (1989): 989-1005.

Malinger, G., et al. “Differential diagnosis in fetuses with absent septum pellucidum.” Ultrasound in Obstetrics and Gynecology: The Official Journal of the International Society of Ultrasound in Obstetrics and Gynecology 25.1 (2005): 42-49.