Cyclopia is birth defect characterized by the failure of the embryonic prosencephalon to properly divide the orbits of the eye into two cavities. Its incidence is one in 200 in miscarried fetuses. Typically, the nose is either missing or replaced with a non-functional nose. This deformity is called the proboscis and usually forms above the center eye or on the back, and is characteristic form of cyclopia called rhinencephaly. Most such embryos are either naturally aborted or are stillborn upon delivery.
Cyclopia occurs when certain proteins are inappropriately expressed, causing the brain to stay whole, rather than developing two distinct hemispheres. This leads to the fetus having one optic lobe (single and underdeveloped eye) and one olfactory lobe (single and ill developed nasal aperture), resulting in the eye and nose malformations of cyclopia.
The prosencephalon or the forebrain is the rostral part of the brain. At the five-vesicle stage, the forebrain separates into the diencephalon (thalamus, hypothalamus, subthalamus, epithalamus and metathalamus) and the telencephalon which develops into the cerebrum. The cerebrum consists of the cerebral cortex, underlying white matter, and the basal ganglia.
The orbit is a bony cavity in the skull that houses the eyeball, the muscles that move the eye (i.e., the extraocular muscles), the lacrimal gland, and the blood vessels and nerves required to supply these structures.
The fetuses that are spontaneously aborted.
It is an elongated nose or snout that is normally observed in vertebrates. Eg: trunk of an elephant.
It is a form of cyclopia where the face is replaced with a non-functioning nose in the form of a proboscis.