<unk>  is an extreme form of porencephaly, which is characterized by a cyst or cavity in the cerebral hemispheres. Although the exact cause of<unk>  remains undetermined in most cases, the most likely general cause is by vascular insult, such as stroke, injury, intrauterine infections, or traumatic disorders after the first trimester of pregnancy. In a number of cases where intrauterine infection was determined to be the causing factor, most involved toxoplasmosis and viral infections such as enterovirus, adenovirus, parvovirus, cytomegalovirus, herpes simplex, Epstein-Barr, and syncytial viruses. Another cause factor is monochorionic twin pregnancies, involving the death of one twin in the second trimester, which in turn causes vascular exchange to the living twin through placental circulation through twin-to-twin transfusion, causing<unk>  in the surviving fetus. One medical journal reports<unk>  as an autosomal inherited disorder with an unknown mode of transmission, causing a blockage of the carotid artery where it enters the cranium; this causes obstruction and damage to the cerebral cortex. Genetic<unk>  is a recessive genetic condition, so both parents must carry the asymptomatic gene and pass it along to their child. There is a 25% chance that both parents will pass the gene to their child, resulting in<unk> . Genetic<unk>  afflicts both males and females in equal numbers. Post-natal brain injury Though<unk>  is typically a congenital disorder, it can occur as a postnatal diagnosis in the aftermath of meningitis, intracerebral infarction, ischemia, or a traumatic brain injury.
Hydranencephaly
Hemihydranencephaly
Microhydranencephaly
Schizencephaly
Megalencephaly
Holoprosencephaly
Lissencephaly
Microlissencephaly