Friday 21 May 2004
Definition: Anencephaly is a designation for congenital absence of the cranial vault with cerebral hemispheres completely missing or decreased to small masses attached to the base of the skull. In anencephaly, the absence of the brain and calvaria can be total or partial. Anencephaly is one of the neural tube defects (NTDs).
The etiology is unknown. Whether the bony tissue or soft brain tissue is a primary factor is also unknown.
congenital absence of the cranial vault
cerebral hemispheres completely missing or decreased to small masses attached to the base of the skull
The absence of the brain can be total or partial.
The absence of thecalvaria can be total (acrania) or partial.
bactracian facial dysmorphism
absent frontal bones
protusion of the eyeballs
- sporadic anencephaly
- familial anencephaly
- associated anencephaly (see Associations)
holoacrania form of anencephaly
bilateral adrenal hypoplasia
- aortic coarctation
- left heart hypoplasia (left ventricular hypoplasia)
short-rib polydactyly syndrome (SRPS) (8267012)
congenital diaphragmatic hernia
cystic renal dysplasia
- Meckel syndrome
familial anencephaly (2333913)
- parental consanguinity (2333913)
NB: Posterior fossa
A study showed 2 morphologic types of the posterior cranial fossa. One type had a fossa cranial morphology close to normal morphology, whereas the other had a malformed and much smaller posterior cranial fossa. The latter condition was presumed to be due to a primary error in chondral and cranial development. (15630528)
neural tube defects (NTDs)
mice that are homozygous for deficiency in the paired class homeobox-containing gene Cart1
Lomholt JF, Fischer-Hansen B, Keeling JW, Reintoft I, Kjaer I. Subclassification of anencephalic human fetuses according to morphology of the posterior cranial fossa. Pediatr Dev Pathol. 2004 Nov-Dec;7(6):601-6. Epub 2004 Nov 17. PMID: 15630528