Table 2.

Classification of Orofacial Cleft (OFC) Based on Embryonic and Phenotypic Characteristics.

Embryonic period	Affected palate	Type of defect
E (early)a	P (primary palate)b	F (fusion defect)
L (late)c	S (secondary palate)d	D (differentiation defect)
EL (both)	PS (both)	FD (both)

^a Early embryonic period: 4 to 7 weeks postconception.

^b Primary palate: lip, premaxilla/maxilla.

^c Late embryonic period: 7 to 12 weeks postconception.

^d Secondary palate: hard palate, soft palate, and uvula.