TABLE 2.

Summary of Craniosynostoses with Causes and Characteristics

Condition	Causes	Characteristics
Positional head deformation	Extrinsic factors	Head usually flat on one side
		Ear & and forehead on ipsilateral side are rotated forward
		Frontal bossing on ipsilateral side
		Flatness of forehead on opposite side
		1:2,000 births
Isolated craniosynostosis	Unknown	Premature fusion of one or more sutures
		Skull cannot expand perpendicularly to the fused suture so excessive growth occurs in a direction parallel to the fused suture
Crouzon syndrome	FGFR2	Autosomal dominant; 1:25,000–60,000
		Craniosynostosis, midface hypoplasia, hypertelorism (wideset eyes), proptosis, beak nose
Apert syndrome	FGFR2	Autosomal dominant; 1:160,000
		Craniosynostosis, midface hypoplasia, hypertelorism, symmetric syndactyly, mental handicap (50%), CP (30%)
Pfeiffer syndrome	FGFR1 & and 2	Autosomal dominant; 1:100,000
		Craniosynostosis, broad features, cloverleaf skull, syndactyly, elbow ankylosis
Saethre-Chotzen syndrome	TWIST	Autosomal dominant
		Craniosynostosis, broad features, syndactyly, beak nose
Carpenter syndrome	RAB23, MEGF8	Autosomal Recessive
		Craniosynostosis, midface hypoplasia, mental handicap, syndactyly