Anencephaly

Anencephaly is a severe congenital neural tube defect resulting from failure of anterior neural tube closure, leading to absence of major portions of the brain and skull. It is typically detected prenatally via ultrasound and elevated maternal alpha-fetoprotein levels. Affected infants are either stillborn or survive only hours to days, with absent cerebral hemispheres and rudimentary brainstem structures. Etiology is multifactorial, involving genetic predisposition and folate deficiency. There is no treatment, and management is limited to supportive care and counseling; prognosis is universally fatal.