a hereditary form of defective midline development of the head and face, including ocular hypertelorism, occult cleft nose and maxilla, and sometimes mental retardation or other defects. Also called median cleft facial syndrome.
frontonasal dysplasia type 1A highly heterogeneous condition (OMIM:136760) defined as two or more of the following:
(1) true ocular hypertelorism;
(2) broadening of the nasal root;
(3) median facial cleft affecting the nose and/or upper lip and palate;
(4) unilateral or bilateral clefting of the alae nasi;
(5) lack of formation of the nasal tip
(6) anterior cranium bifidum occultum (see OMIM:168500); and
(7) a V-shaped or widow's peak frontal hairline.
Caused by defects of ALX3, which encodes a nuclear protein that functions as a transcriptional regulator of differentiation and development.