Anencephaly (aka Cranioschisis)
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Definition
- Cranioschisis (aka anencephaly or cranial dysraphism) is neural tube defect that specifically involves failure of anterior neuropore closure.
- Because of this failure, there is acrania (absence of a skull) and failure of cerebral development (absence of a brain).
Clinical Presentation
- Presents with an absence of cranium (acrania) and failure of forebrain (telencephalon) development.
- Infants survive just hours (failing to ever reach consciousness).
Diagnostic Imaging
- Late in the first trimester, at ~ 11 weeks gestation, anencephaly can be observed via ultrasonography: the fetus appears to have a "frog-like" appearance.
- Angiomatous stroma (an undifferentiated neural tissue that mimics the appearance of brain) is present above the orbits and skull base and is exposed to the environment.
References
- “Anencephaly - NORD (National Organization for Rare Disorders).” NORD (National Organization for Rare Disorders) (blog). Accessed June 4, 2018. https://rarediseases.org/rare-diseases/anencephaly/.
- “Luca Hill Acrania and Anencephaly Foundation | Acrania.” Luca Hill Acrania and Anencephaly Foundation. Accessed June 4, 2018. https://www.lhaaf.org/claims.
- “The Fetal Medicine Foundation.” Accessed June 4, 2018. https://fetalmedicine.org/education/fetal-abnormalities/brain/acrania.
Images Adapted From
- Front and side views of anencephalic fetus
- The Anterosuperior View of the Head of an Anencephalic Fetus Demonstrates the Disorganized Connective Tissue Membrane That, in the Absence of the Calvarium, Covers the Top of the Skull. January 13, 2002.
- Ultrasound of anencephalic fetus
- Dilmen, Nevit. English: Ultrasound Scan of 28 Week Anencephalic Fetus. 1999. Own work. https://commons.wikimedia.org/wiki/File:Ultrasound_Scan_ND_066.jpg.