Infants usually present at birth with skull deformities resembling some variant of acrocephalosyndactyly. Some or all of the skull sutures may be fused. In some individuals craniectomy is necessary while others have normal brain development. Few patients have evidence of abnormal neurological development and psychometric testing reveals IQ's in the normal range. The midface is flattened with sometimes severe maxillary hypoplasia. No hand deformities are present.
There may be cutaneous syndactyly of the second and third toes. Variable tarsal fusion is often present. The great toe may be abnormally broad and deviated medially. The first metatarsals and proximal phalanges of the great toes are generally broad.
The phenotype is highly variable and even among individuals in genetically more homogeneous populations such as the Old Order Amish the range of facial, skull, and digital anomalies include features found among all of the craniosynostosis syndromes except for Apert syndrome.
