Anencephaly is a developmental anomaly characterized by a fetus that has no calvarium, with a lack of most or all of the fetus' brain tissue. Anencephaly belongs to a collective group known as neural tube defects (NTD) and is a result of the neural tube failing to close in its rostral end during fetal development. [ http://www.ncbi.nlm.nih.gov/pubmed/32706613 http://www.ncbi.nlm.nih.gov/pubmed/31424828 ]