When a baby is the womb and do not develop a full brain what is it call?

When a baby in the womb does not develop a full brain, the condition is called "anencephaly." This serious congenital condition occurs when the neural tube does not close properly, leading to partial or complete absence of the brain and skull. Infants born with anencephaly typically do not survive long after birth, as the condition is incompatible with life.