National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Carpenter syndrome


Other Names:
Acrocephalopolysyndactyly type 2; ACPS 2; Acrocephalosyndactyly, type II; Acrocephalopolysyndactyly type 2; ACPS 2; Acrocephalosyndactyly, type II; Carpenter syndrome 1; CRPT1 See More
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Carpenter syndrome is a condition characterized by premature fusion of skull bones (craniosynostosis); finger and toe abnormalities; and other developmental problems. The features in affected people vary. Craniosynostosis can give the head a pointed appearance; cause asymmetry of the head and face; affect the development of the brain; and cause characteristic facial features. Other signs and symptoms may include dental abnormalities; vision problems; hearing loss; heart defects; genital abnormalities; obesity; various skeletal abnormalities; and a range of intellectual disability. Carpenter syndrome can be caused by mutations in the RAB23 or MEGF8 gene and is inherited in an autosomal recessive manner.[1] Treatment focuses on the specific features in each affected person.[2] Life expectancy is shortened but very variable.[1]
Last updated: 2/5/2015
The signs and symptoms of Carpenter syndrome can vary greatly, even within members of the same family.[1] The main features include premature closure of certain skull bones (craniosynostosis), distinctive facial characteristics, and/or abnormalities of the fingers and toes (digits).[2] People with Carpenter syndrome often have intellectual disability (from mild to profound), but some affected people have normal intelligence.[1]

Craniosynostosis prevents the skull from growing normally and can cause a pointed appearance of the head; asymmetry of the head and face; increased pressure within the skull; and characteristic facial features. Facial features may include a flat nasal bridge; down-slanting palpebral fissures (the outside corners of the eye); low-set and abnormally shaped ears; underdeveloped jaws; and abnormal eye shape. Vision problems are common. Some people also have dental abnormalities such as small baby teeth. Abnormalities of the fingers and toes may include fusion of the skin between digits; short digits; or extra digits.

Other signs and symptoms may include obesity, umbilical hernia, hearing loss, heart defects, and other skeletal abnormalities such as as deformed hips, kyphoscoliosis, and knees that angle inward. Nearly all males have genital abnormalities such as undescended testes. A few affected people have organs or tissues within the torso that are in reversed positions.[1]
Last updated: 2/5/2015

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

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Medical Terms Other Names
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HPO ID
100% of people have these symptoms
Brachydactyly
Short fingers or toes
0001156
Finger syndactyly 0006101
Toe syndactyly
Fused toes
Webbed toes
[ more ] 		0001770
80%-99% of people have these symptoms
Craniosynostosis 0001363
Cryptorchidism
Undescended testes
Undescended testis
[ more ] 		0000028
External genital hypoplasia
Underdevelopment of external reproductive organs
0003241
Intellectual disability
Mental deficiency
Mental retardation
Mental retardation, nonspecific
Mental-retardation
[ more ] 		0001249
Obesity
Having too much body fat
0001513
Oxycephaly 0000263
30%-79% of people have these symptoms
Abnormal cornea morphology 0000481
Broad thumb
Broad thumbs
Wide/broad thumb
[ more ] 		0011304
Cloverleaf skull 0002676
Genu valgum
Knock knees
0002857
Postaxial hand polydactyly
Extra little finger
Extra pinkie finger
Extra pinky finger
[ more ] 		0001162
Preaxial foot polydactyly 0001841
5%-29% of people have these symptoms
Kyphoscoliosis 0002751
Patent ductus arteriosus 0001643
Polysplenia
Multiple small spleens
0001748
Talipes equinovarus
Club feet
Club foot
Clubfeet
Clubfoot
[ more ] 		0001762
Umbilical hernia 0001537
Percent of people who have these symptoms is not available through HPO
Abnormality of the pinna
Abnormally shaped ears
Auricular malformation
Deformed ears
Malformed ears
[ more ] 		0000377
Agenesis of permanent teeth
Failure of development of permanent teeth
Missing teeth
[ more ] 		0006349
Aplasia/Hypoplasia of the corpus callosum 0007370
Aplasia/Hypoplasia of the middle phalanges of the hand
Absent/small middle finger bone of the hand
Absent/underdeveloped middle finger bone of the hand
[ more ] 		0009843
Aplasia/Hypoplasia of the middle phalanges of the toes
Absent/small middle bones of toe
Absent/underdeveloped middle bones of toe
[ more ] 		0010194
Atrial septal defect
An opening in the wall separating the top two chambers of the heart
Hole in heart wall separating two upper heart chambers
[ more ] 		0001631
Autosomal recessive inheritance 0000007
Brachycephaly
Short and broad skull
0000248
Camptodactyly
Permanent flexion of the finger or toe
0012385
Cerebral atrophy
Degeneration of cerebrum
0002059
Clinodactyly of the 5th finger
Permanent curving of the pinkie finger
0004209
Complete duplication of proximal phalanx of the thumb
Complete duplication of the innermost bone of the thumb
0009608
Conductive hearing impairment
Conductive deafness
Conductive hearing loss
[ more ] 		0000405
Coronal craniosynostosis 0004440
Coxa valga 0002673
Depressed nasal bridge
Depressed bridge of nose
Flat bridge of nose
Flat nasal bridge
Flat, nasal bridge
Flattened nasal bridge
Low nasal bridge
Low nasal root
[ more ] 		0005280
Duplication of the proximal phalanx of the hallux
Duplication of the innermost bone of big toe
0010093
Epicanthus
Eye folds
Prominent eye folds
[ more ] 		0000286
Flared iliac wings 0002869
Genu varum
Outward bow-leggedness
Outward bowing at knees
[ more ] 		0002970
High palate
Elevated palate
Increased palatal height
[ more ] 		0000218
Hydronephrosis 0000126
Hydroureter 0000072
Hypoplasia of the maxilla
Decreased size of maxilla
Decreased size of upper jaw
Maxillary deficiency
Maxillary retrusion
Small maxilla
Small upper jaw
Small upper jaw bones
Upper jaw deficiency
Upper jaw retrusion
[ more ] 		0000327
Joint contracture of the hand 0009473
Lambdoidal craniosynostosis 0004443
Large foramen magnum
Big foramen magnum
0002700
Lateral displacement of patellae 0006397
Low-set ears
Low set ears
Lowset ears
[ more ] 		0000369
Malar flattening
Zygomatic flattening
0000272
Metatarsus adductus
Front half of foot turns inward
0001840
Microcornea
Cornea of eye less than 10mm in diameter
0000482
Micrognathia
Little lower jaw
Small jaw
Small lower jaw
[ more ] 		0000347
Midface retrusion
Decreased size of midface
Midface deficiency
Underdevelopment of midface
[ more ] 		0011800
Omphalocele 0001539
Opacification of the corneal stroma 0007759
Optic atrophy 0000648
Persistence of primary teeth
Delayed loss of baby teeth
Failure to lose baby teeth
Retained baby teeth
[ more ] 		0006335
Preauricular pit
Pit in front of the ear
0004467
Precocious puberty
Early onset of puberty
Early puberty
[ more ] 		0000826
Pseudoepiphyses of the proximal phalanges of the hand 0010275
Pulmonic stenosis
Narrowing of pulmonic valve
0001642
Sacral dimple
Spinal dimple
0000960
Sagittal craniosynostosis
Early closure of midline skull joint
Midline skull joint closes early
[ more ] 		0004442
Scoliosis 0002650
Sensorineural hearing impairment 0000407
Shallow acetabular fossae 0003182
Short neck
Decreased length of neck
0000470
Short stature
Decreased body height
Small stature
[ more ] 		0004322
Spina bifida occulta 0003298
Telecanthus
Corners of eye widely separated
0000506
Tetralogy of Fallot 0001636
Transposition of the great arteries 0001669
Underdeveloped supraorbital ridges
Flattened bony protrusion above eyes
0009891
Ventricular septal defect
Hole in heart wall separating two lower heart chambers
0001629
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Last updated: 7/1/2020

Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

Organizations Providing General Support

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

  • Genetics Home Reference contains information on Carpenter syndrome. This website is maintained by the National Library of Medicine.
  • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.

In-Depth Information

  • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Carpenter syndrome. Click on the link to view a sample search on this topic.

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know. Submit a new question

  • I would like to have some information about Carpenter syndrome. I can find information about the physical aspects of the syndrome. Are there are certain behavioral characteristics? See answer


  1. Carpenter syndrome. Genetics Home Reference. May, 2013; http://ghr.nlm.nih.gov/condition/carpenter-syndrome. Accessed 2/5/2015.
  2. Carpenter syndrome. NORD. November 3, 2010; http://www.rarediseases.org/rare-disease-information/rare-diseases/byID/612/viewAbstract. Accessed 2/5/2015.