= CRANIOFACIAL SYNOSTOSIS / DYSOSTOSIS

= Apert syndrome without syndactyly

= skull + cranial base deformities characterized by craniosynostosis, maxillary hypoplasia, shallow orbits, ocular proptosis, bifid uvula, cleft palate

Prevalence: 1÷25,000

Etiology: autosomal dominant inheritance (in 67%)

Associated intracranial anomalies:

anomalous venous drainage, hydrocephalus (often progressive), Chiari I malformation (71%)

• parrot-beak nose; strabismus; deafness; mental retardation
• dental abnormalities; bifid uvula
• acanthosis nigrans (= hyperpigmented hyperkeratotic lesions on neck + near joint flexures)

• premature craniosynostosis: acro(oxy)cephaly / brachycephaly / scaphocephaly / trigonocephaly / “cloverleaf” skull
• hypertelorism + exophthalmos ← shallow orbits
• hypoplastic maxilla → relative prominence of mandible
• cleft palate
• calcification of stylohyoid ligament (in 50% of patients >4 years of age)
• C2–C5 spine abnormalities (in up to 40%)
• elbow malformation (18%)
• minor hand deformities (10%)
• visceral anomalies (7%)
• musculoskeletal deformities (7%) but NO limb anomaly

OB-US:

• cloverleaf appearance (coronal view) + bilateral frontal indentations (axial view) of skull
• increased interorbital distance + ocular proptosis
• mild ventriculomegaly