A relatively common birth defect of the brain, holoprosencephaly occurs when the developing brain fails to completely divide into two halves. It can also affect facial features, causing closely spaced eyes, a small head and sometimes cleft lip or palate. In many cases, the defect is so severe that the baby dies before birth. In less severe cases, the baby is born with normal or near-normal brain development and facial appearance.
Holoprosencephaly can be classified three ways:
- Alobar: The brain has not divided at all, and facial abnormalities can be severe.
- Semilobar: The brain’s hemispheres are somewhat divided.
- Lobar: Considerable division. In some cases, the baby’s brain may be nearly normal.
Treatment varies for individuals, but it is largely symptomatic and supportive.