Because the infant's initial appearance and early behavior appear relatively normal, diagnosis of hydranencephaly may take several months. Doctors who suspect the condition usually confirm their diagnosis by means of transillumination, a procedure in which light is passed through body tissues, as well as CT and MRI studies. Hydranencephaly has no cure. Treatment is symptomatic and supportive. A shunt may be installed to control hydrocephalus.
Prognosis overall is poor, however, with death generally occurring in the first year.
Iniencephalic infants are short, with disproportionately large heads. Newborns with iniencephaly seldom live more than a few hours. The mother, too is at risk, because the distorted fetal body can cause serious injury to her during pregnancy or the birthing process. It results when nerve cells in the fetal neural tube fail to move to the proper location as the fetus's central nervous system develops during pregnancy. This defective neuronal migration, as it is called, may be caused by intrauterine or fetal viral infections during the first trimester, insufficient blood supply to the brain early in pregnancy, or a genetic disorder.