What is the Difference Between Exencephaly and Anencephaly?

Exencephaly and anencephaly are both congenital central nervous system abnormalities that arise due to neural tube defects. They are related to the central nervous system and head, and both disorders occur during embryonic development. Both conditions are lethal and cannot be treated. However, there are some differences between the two:

• Exencephaly is characterized by the presence of a relatively normal-appearing embryonic or fetal brain that is not encased in the calvarium. It is considered to be an embryological precursor of anencephaly. Exencephaly is a rare malformation of the neural tube with a large amount of protruding brain tissue and absence of calvarium.
• Anencephaly is defined as the complete or partial absence of the cranium. It is characterized by the absence of major portions of the skull and scalp due to the failure of the rostral neuropore to close. Anencephaly is the most common neural tube disorder seen and occurs in 1 in 5 per 1000 live births, more commonly in females.

In summary, the key difference between exencephaly and anencephaly is that exencephaly is a cephalic disorder in which a large amount of brain tissue is present outside the skull, while anencephaly is a cephalic disorder characterized by the absence of a major portion of the skull and scalp.

Comparative Table: Exencephaly vs Anencephaly

Exencephaly and anencephaly are both cephalic disorders arising due to neural tube defects. They are related to the central nervous system and head, and occur during embryonic development. Both disorders are lethal and cannot be treated. The main differences between exencephaly and anencephaly are as follows:

Exencephaly is considered to be an embryological precursor of anencephaly. In exencephaly, there is only a vascular layer of epithelium covering the brain tissue, which is slowly degraded during gestation by the amniotic fluid and degenerates into anencephaly.