Greig cephalopolysyndactyly syndrome is a disorder that affects development of the limbs, head, and face.

This disorder is also characterized by widely spaced eyes (ocular hypertelorism), an abnormally large head size (macrocephaly), and a high, prominent forehead.

Rarely, affected individuals may have more serious medical problems including seizures and developmental delay.

By interacting with certain genes at specific times during development, the GLI3 protein plays a role in the normal shaping (patterning) of many organs and tissues before birth.

It remains unclear how a reduced amount of this protein disrupts early development and causes the characteristic features of Greig cephalopolysyndactyly syndrome.

[1] Rare instances of this disorder are sporadic, and occur in people with no history of the condition in their family.

The main form of diagnosis is presumptive, if the person has the usual triad of preaxial polydactyly with cutaneous syndactyly of at least one limb, macrocephaly, and hypertelorism.