Pai syndrome is an idiopathic developmental disorder characterized by median cleft of the upper lip (MCL), midline polyps of the facial skin and nasal mucosa, and pericallosal lipomas. Hypertelorism with ocular anomalies are also observed, generally with normal neuropsychological development.

A neural tube defect characterized by sac-like protrusions of the brain and the membranes that cover it through openings in the skull.