Ablepharon-macrostomia syndrome is an extremely rare congenital disorder that is caused by a dominant mutation in the TWIST2 gene, which is highly expressed in the craniofacial mesenchyme, controls the development of mesenchymal tissues, and is also overly expressed during embryonic development in the craniofacial region.³,⁴,⁵ The TWIST2 gene thus regulates mesenchymal stem cell differentiation and directs the development of chondrogenic and dermal tissues.⁵

Only 21 cases of ablepharon-macrostomia syndrome are reported in the literature.³,⁴,⁵,⁶,⁷ The affected individuals present with ablepharon or more correctly microblepharon.³ Affected individuals have extremely shortened anterior lamellae with a well-formed mucocutaneous junction at the upper as well as the lower eyelid margins (Figure 24.1). The tarsal plates are hypoplastic and redundant, and chemotic palpebral conjunctiva is universally observed.³ The orbital septum and the levator aponeurosis are usually spared but may be thinned.³,⁶ In light of these findings, some authors believe that the name ablepharon-macrostomia syndrome is a misnomer and recommend changing the name to microblepharon-macrostomia.³,⁴ Because of marked anterior lamellar shortening, the upper eyelid margin is very close to the eyebrows, and there are usually no eyelashes.⁶ These neonates are also typically born with corneal exposure.³ Corneal erosions develop on postnatal day 1 or 2, proceeding very rapidly to corneal opacification and possibly perforation.⁷ Other ocular abnormalities include nystagmus and strabismus.⁴