379 - The Incidence of Septo-Optic Dysplasia in Neonates with an Absent Cavum Septum Pellucidum Identified During Routine Prenatal Imaging

Poster Number: 379
Publication Number: 379.3207

Background: An absent cavum septum pellucidum (CSP) can be detected on routine prenatal imaging and has been linked to abnormal brain development, particularly septo-optic dysplasia (SOD). SOD is a congenital anomaly diagnosed by the presence of two or more features of the classic triad: (i) optic nerve hypoplasia (ONH), (ii) pituitary hormone abnormalities, and (iii) midline brain defects. However, literature has not clearly defined this connection, as estimates of the incidence of SOD in patients with this imaging finding vary between 18-67%. An accurate diagnosis is crucial as delayed diagnosis of SOD can lead to poor outcomes.

Objective: To determine the incidence of SOD in patients with a prenatal finding of an absent CSP, agenesis of the corpus callosum (ACC) or dysgenesis of the corpus collosum (DCC).

Design/Methods: This retrospective chart review investigated neonates prenatally diagnosed with an absent CSP, ACC, or DCC who were admitted to a single quaternary academic medical center in the Pacific Northwest between 05/01/2016 and 02/28/2023. This prenatal diagnosis prompts a routine and protocolized workup for SOD including laboratory evaluation, imaging and specialty consultation. Sociodemographic and clinical data were collected for eligible neonates and their birthing person.

Results: Of the 87 subjects prenatally diagnosed with absent CSP, ACC and/or DCC, 35.6% (n=31) were diagnosed postnatally with SOD after receiving ACTH stimulation tests and optic nerve evaluations as part of the SOD workup. Of the 31 subjects diagnosed with SOD and midline brain defects, 25.3% (n=22) had ONH, 3.45% (n=3) had endocrinopathies, and 6.9% (n=6) had both ONH and endocrinopathies. Of the nine total subjects with endocrinopathies, seven subjects had adrenal insufficiency, one had hypothyroidism, and one had growth hormone deficiency.

Conclusion(s): Postnatal diagnosis of SOD was confirmed in 35.6% of cases of prenatally-diagnosed absent CSP, ACC, or DCC. Although the observed incidence of SOD in our study is lower than some current literature estimates, this work supports the routine use of a complete postnatal SOD workup for patients with these prenatal imaging findings to avoid the consequences of a delayed diagnosis.