Anencephaly is a serious birth defect that occurs when a baby is born without parts of the brain and skull. This condition happens during early pregnancy when the neural tube, which forms the brain and spinal cord, does not close completely. As a result, the baby may have a small or missing brain and may not survive long after birth. Babies with anencephaly are usually born with a few basic reflexes but lack higher brain functions. Most affected infants do not live beyond a few hours or days after birth. There is currently no cure for this condition, and it is often diagnosed through ultrasound during pregnancy.