Denouement and Discussion
Clinical manifestations are orbital hypotelorism, nose with a single nostril, microcephaly, and holoprosencephaly. These children usually do not survive the first month of life and apparently have severe neurologic impairment. Other congenital anomalies may also be present. Cebocephaly is in the middle of a spectrum of median facial anomalies that are associated with holoprosencephaly; it is a result of abnormal development of the forebrain. The most severe facial defect in the spectrum is cyclopia, which involves a single median orbit and a proboscis above the orbit. Ethmocephaly refers to extreme hypotelorism with a proboscis that may be absent, single, or double. Premaxillary agenesis, at the other end of the spectrum, consists of ocular hypotelorism, a flattened nose, and a median cleft lip.
This disorder usually occurs sporadically. Chromosomal abnormalities, particularly trisomy 13 and 18 syndromes, have been reported. Autosomal recessive inheritance has been postulated in two affected siblings with normal