Apert Syndrome [Q87.0]
Dr. med. Imma Rost, Dipl.-Biol. Christina Sofeso
The Apert syndrome has an incidence of 1:50,000–100,000 and accounts for approximately 5% of all cases of craniosynostoses. Coronal, sagittal, and lambdanoid suture are most commonly affected, resulting in a turribrachycephaly with midface hypoplasia, exophthalmos, hypertelorism and relative mandibular prognathism. The anterior fontanel is generally enlarged and its closure is delayed. The palate can be narrow and high — a cleft palate may be present as well. Severe syndactyly of the hands and feet is characteristic and at least digits II-IV are completely fused together most of the time. Thumbs and great toes are usually broad and may present radial deviation. Associated malformations such as fusions of cervical vertebrae may occur. Intelligence is below average in about 50% of affected individuals.
In 98% of all cases Apert syndrome occurs sporadically and only in 2% it is inherited in an autosomal dominant pattern. If it occurs sporadically, the paternal age is beyond average. The causative mutations are always located on the paternal allele (paternal age effect). 99% of affected patients carry one of two missense mutations in the FGFR2 gene (S252W or P253R).