Holoprosencephaly spectrum

(A) The mildest forms of holoprosencephaly present with microcephaly, microphthalmia, ocular hypotelorism, midfacial hypoplasia, and cleft lip with or without cleft palate.
(B) Features of cebocephaly include an absent or defective single-nostril nose and closely-set eyes (hypotelorism).
(C) Ethmocephaly is characterized by small, narrow-set eyes (hypotelorism and microphthalmia) separated by a primitive, nonfunctioning nasal structure (proboscis).
(D) Cyclopia is marked by a single central orbital fossa and proboscis. The globe can be absent, underdeveloped, or apparently normal, and there can be 1 or 2 globes.