Acrocephalopolysyndactyly is a group of several syndromes consisting of Apert syndrome (Acrocephalosyndactyly, Type I), Carpenter syndrome (Acrocephalosyndactyly, Type II), Saethre-Chotzen syndrome (Acrocephalosyndactyly, Type III), and Pfeiffer syndrome (Acrocephalosyndactyly, Type V), whose basic features are craniosynostosis and polysyndactyly. Carpenter syndrome is of autosomal recessive inheritance and classically consists of acrocephaly with variable synostosis of sagittal, lambdoid and coronal sutures. The most common clinical features of the syndrome are syndactyly, polydactyly, especially preaxial polydactyly of toes, congenital heart disease, intellectual disability, hypogonadism, obesity, umbilical hernia, coxa vara, pes varus and clinodactyly. The clinical spectrum and additional malformations in Carpenter syndrome may show considerable differences. Besides common clinical presentation, different skeletal abnormalities as genu valgum, lateral displacement of patella, poor development of acetabula, absent coccyx, spina bifida occulta and kyphoscoliosis may be seen. Dental developmental abnormalities, hypodontia, low-set ears or malformed ears, epicanthal folds, depressed nasal bridge and thick neck may also accompany the major clinical findings.
Carpenter syndrome-1 is associated with mutations in RAB23 gene.