Acrocephalosyndactylia (or acrocephalosyndactyly) is the common presentation of craniosynostosis and syndactyly.

There are approximately three hundred known cases of Carpenter Syndrome in the United States. Only 1 in 1 million live births will result in an infant affected by Carpenter Syndrome (RN, 2007).

Carpenter Syndrome is an autosomal recessive disease which means both parents must have the faulty genes in order to pass the disease onto their children. Even if both parents possess the faulty gene there is still only a twenty five percent chance that they will produce a child affected by the syndrome. Their children who do not have the disease will still be carriers and possess the ability to pass the disease onto their offspring if their spouse is also a carrier of the particular gene.

Although no cause has been officially confirmed, researchers speculate the disease might result from a genetic mutation that sporadically occurs for unknown reasons.

It has several different types:

- type 1 - Apert syndrome

- type 2 - Crouzon syndrome

- type 3 - Saethre-Chotzen syndrome

- type 5 - Pfeiffer syndrome

A related term, "acrocephalopolysyndactyly" (ACPS), refers to the inclusion of polydactyly to the presentation. It also has multiple types:

- type 1 - Noack syndrome; now classified with Pfeiffer syndrome

- type 2 - Carpenter syndrome

- type 3 - Sakati-Nyhan-Tisdale syndrome

- type 4 - Goodman syndrome; now classified with Carpenter syndrome

- type 5 - Pfeiffer syndrome

It has been suggested that the distinction between "acrocephalosyndactyly" versus "acrocephalopolysyndactyly" should be abandoned.

Carpenter syndrome has been associated with mutations in the RAB23 gene, which is located on chromosome 6 in humans. Additionally, three key SNPs in the MEGF8 gene, located on chromosome 19 at 19q13.2, have been identified as primary causes of Carpenter syndrome.

Sakati–Nyhan–Tisdale syndrome, also called acrocephalopolysyndactyly type III, is a rare genetic disorder that has been associated with abnormalities in the bones of the legs, congenital heart defects and craniofacial defects. The syndrome belongs to a group of rare genetic disorders known as acrocephalopolysyndactyly or ACPS, for short.