What are the signs and symptoms of Apert syndrome? Apert syndrome is characterized by the premature fusion of certain skull bones (craniosynostosis). This early fusion prevents the skull from growing normally and affects the shape of the head and face, effectively resulting in a cone or tower shaped skull. In addition, a varied number of fingers and toes are fused together (syndactyly). Many of the characteristic facial features of Apert syndrome result from the premature fusion of the skull bones. The head is unable to grow normally, which leads to a sunken appearance in the middle of the face, bulging and wide-set eyes, a beaked nose, and an underdeveloped upper jaw leading to crowded teeth and other dental problems. Shallow eye sockets can cause vision problems. Early fusion of the skull bones also affects the development of the brain, which can disrupt intellectual development. Cognitive abilities in people with Apert syndrome range from normal to mild or moderate intellectual disability. Individuals with Apert syndrome have webbed or fused fingers and toes (syndactyly). The severity of the fusion varies. Less commonly, people with this condition have extra fingers or toes (polydactyly). Additional signs and symptoms of Apert syndrome may include hearing loss, unusually heavy sweating (hyperhidrosis), oily skin with severe acne, patches of missing hair in the eyebrows, fusion of spinal bones in the neck (cervical vertebrae), and recurrent ear infections that may be associated with an opening in the roof of the mouth (a cleft palate). The Human Phenotype Ontology provides the following list of signs and symptoms for Apert syndrome. If the information is available, the table below includes how often the symptom is seen in people with this condition. You can use the MedlinePlus Medical Dictionary to look up the definitions for these medical terms. Signs and Symptoms Approximate number of patients (when available) Conductive hearing impairment 90% Depressed nasal bridge 90% Frontal bossing 90% Malar flattening 90% Proptosis 90% Toe syndactyly 90% Abnormality of the fontanelles or cranial sutures 50% Aplasia/Hypoplasia of the corpus callosum 50% Aplasia/Hypoplasia of the thumb 50% Cognitive impairment 50% Convex nasal ridge 50% Delayed eruption of teeth 50% Facial asymmetry 50% Hypertelorism 50% Hypertension 50% Mandibular prognathia 50% Strabismus 50% Vertebral segmentation defect 50% Arnold-Chiari malformation 7.5% Choanal atresia 7.5% Cleft palate 7.5% Cloverleaf skull 7.5% Corneal erosion 7.5% Ectopic anus 7.5% Hydrocephalus 7.5% Limb undergrowth 7.5% Optic atrophy 7.5% Ovarian neoplasm 7.5% Respiratory insufficiency 7.5% Sensorineural hearing impairment 7.5% Ventriculomegaly 7.5% Visual impairment 7.5% Postaxial hand polydactyly 5% Preaxial hand polydactyly 5% Absent septum pellucidum - Acne - Acrobrachycephaly - Agenesis of corpus callosum - Anomalous tracheal cartilage - Arachnoid cyst - Arnold-Chiari type I malformation - Autosomal dominant inheritance - Bifid uvula - Brachyturricephaly - Broad distal hallux - Broad distal phalanx of the thumb - Broad forehead - Cervical vertebrae fusion (C5/C6) - Choanal stenosis - Chronic otitis media - Coronal craniosynostosis - Cryptorchidism - Cutaneous finger syndactyly - Delayed cranial suture closure - Dental malocclusion - Esophageal atresia - Flat face - Growth abnormality - Hearing impairment - High forehead - Humeroradial synostosis - Hydronephrosis - Hypoplasia of midface - Intellectual disability - Large fontanelles - Limbic malformations - Megalencephaly - Narrow palate - Overriding aorta - Posterior fossa cyst - Pyloric stenosis - Shallow orbits - Synostosis of carpal bones - Vaginal atresia - Ventricular septal defect - The Human Phenotype Ontology (HPO) has collected information on how often a sign or symptom occurs in a condition. Much of this information comes from Orphanet, a European rare disease database. The frequency of a sign or symptom is usually listed as a rough estimate of the percentage of patients who have that feature. The frequency may also be listed as a fraction. The first number of the fraction is how many people had the symptom, and the second number is the total number of people who were examined in one study. For example, a frequency of 25/25 means that in a study of 25 people all patients were found to have that symptom. Because these frequencies are based on a specific study, the fractions may be different if another group of patients are examined. Sometimes, no information on frequency is available. In these cases, the sign or symptom may be rare or common.