Midline Craniofacial-Cerebral Dysraphism
- Midline craniofacial dysraphisms are classified into two groups:
Group A: in which the clefting involves the upper lip (with or without the nose) and is associated with basal encephalocele, callosal agenesis (rarely lipoma), and optic nerve dysplasias including optic pits, colobomas, persistent hyperplastic primary vitreous with hyaloid artery and morning glory syndrome, and
Group B: in which the clefting primarily affects the nose and consists of patients with median cleft face syndrome. - Experiments conducted in mice have demonstrated clefting resulting from defects in the aristaless-related genes (Alx3 and Alx4), which are upstream regulators of sonic hedgehog.
- Such a relationship has yet to be conclusively demonstrated in humans.