Acrania

Acrania refers to a rare congenital disorder characterized by the partial or complete absence of the cranial vault (the upper part of the skull). This condition is usually incompatible with life, although there have been rare cases of prolonged survival. Acrania is often detected during prenatal ultrasound screenings. It is considered a neural tube defect that occurs during early embryonic development, specifically affecting the formation of the mesenchyme that is necessary for skull development. Acrania is distinct from anencephaly, although the two conditions can be difficult to differentiate. Anencephaly involves the absence of a major portion of the brain, skull, and scalp, whereas acrania primarily involves the absence of the skull. Some researchers suggest that acrania may be a precursor to anencephaly. The exact causes of acrania are often unknown but may involve genetic factors, environmental influences, or nutritional deficiencies, such as folate deficiency during pregnancy.