What is Holoprosencephaly?

The following is information that I have gathered from numerous articles, research studies, and websites.
Definition:
Holoprosencephaly is a profound fetal brain anomaly that cannot be altered or treated. It is a disorder in which there is a failure of the front part of the brain to properly separate into what is commonly know as the right and left halves of the brain. This lack of separation is often accompanied by abnormalities of the face and skull. Holoprosencephaly may occur individually or as a component of a larger disorder.
A chromosomal abnormality is more likely to be present if extrafacial abnormalities are detected on sonography.
Types of holoprosencephaly:
Holoprosencephaly comes in three different types: alobar, semilobar, and lobar. Each of these classifications is based on the amount of separation between what is commonly known as the left and right halves of the brain.
Alobar holoprosencephaly is considered to be the most severe form of the disease, in which the separation between the two halves, or hemispheres, completely fails to develop. This was Lily's diagnosis.
Semilobar holoprosencephaly represents holoprosencephaly of the moderate type, where some separation between the hemispheres has occurred.
Lobar holoprosencephaly represents the least severe type of holoprosencephaly in which the hemispheres are almost, but not completely, divided.
Prognosis:
Most severely affected patients die at birth or in the first 6 months of life. Survival, with variable mental retardation, occurs in mild cases. Holoprosencephaly is highly lethal during fetal life. It is estimated that only 3% survive long enough to be considered a live birth.
For more information about holoprosencephaly visit www.sonoworld.com/fetus/page.aspx?id=115