Contributor: Gordon K. Klintworth
Apert syndrome (acrocephalosyndactyly type I, OMIM #101200) is a rare distinct inherited syndrome with craniosynostosis and limb abnormalities. It has an autosomal dominant with high penetrance and variable expressivity and is one variety of acrocephalopolysyndactyly and one of five syndromes with craniosynostosis caused by different allelic mutations in the FGFR2 gene (others are Crouzon syndrome, Pfeiffer syndrome, Jackson-Weiss syndrome and Beare-Stevenson syndrome). The mutations occur within the putative linker region between the IgII and include a (VV269-270 deletion). The manifestations include bony syndactyly of the hands and feet occur, brachycephaly, acrobrachycephaly, plagiocephaly, large fontanelles, low frontal hairline, craniosynostosis (isolated coronal or multiple), microcephaly, growth retardation, short stature, mental retardation, ear anomalies and conductive hearing loss, small posteriorly ritate dears with prominent crura, a deviated nasal septum with a parrot-beaked nose, high arched narrow palate, cleft palate, defects in the vertebral column, a large nevus on the back, and cryptorchism. Less common abnormalities involve the skin, skeleton, brain and other internal organs. The ophthalmic abnormalities include ptosis, antimongoloid slant, epicanthal folds [epicanthal fold], hypertelorism, a brow irregularity, proptosis, strabismus (exotropia or esotropia), optic atrophy, partial ophthalmoplegia, cataract, refractive error, stenosis of the tear duct and dystopia canthorum. In the absence of limb abnormalities it may be difficult to differentiate acrocephalosyndactyly type I from Saethre-Chotzen syndrome, Crouzon syndrome, Jackson-Weiss syndrome, Pfeiffer syndrome and other conditions with craniosynostosis.