Rare Hematology News

Disease Profile

Trismus-pseudocamptodactyly syndrome

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.


US Estimated

Europe Estimated

Age of onset






Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.

Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other names (AKA)

Hecht syndrome; Dutch-Kentucky syndrome; Distal arthrogryposis type 7;


Congenital and Genetic Diseases


Trismus-pseudocamptodactyly syndrome (TPS) is a disorder of muscle development and function.[1] It is characterized by short muscles and tendons resulting in limited range of motion of the hands, legs, and mouth.[1] The most serious complications of the condition occur as a result of the limited mobility of the mouth (trismus).[2] TPS is typically reported to be inherited in an autosomal dominant manner and is caused by mutations in the MYH8 gene.[1][3] Treatment may involve surgical correction and physical therapy.[1][2]


While the symptoms of trismus-pseudocamptodactyly syndrome vary from patient to patient, characteristic symptoms include the inability to open the mouth wide (e.g., less than 6 mm, just under 1/4th of an inch) and shortened muscles, including of the hamstrings and calf muscles. As a result of shortened muscles some infants with trismus-pseudocamptodactyly syndrome have closed or clinched fists, club foot, metatarsus adductus, and calcaneovalgus (where the foot bends sharply at the ankle) at birth.[1][2] Children with this syndrome may crawl on their knuckles.[2] In adulthood the syndrome may cause reduced hand dexterity,[1] however hand limitation does not often interfere with normal function.[2] The most serious complications of the condition occur as a result of the limited mobility of the mouth, including impairment of adequate calorie intake, speech development, dental care, and difficulty with intubation.[2]

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.

Medical Terms Other Names
Learn More:
80%-99% of people have these symptoms
Abnormality of the musculature
Muscular abnormality
Limitation of joint mobility
Decreased joint mobility
Decreased mobility of joints
Limited joint mobility
Limited joint motion

[ more ]

Short stature
Decreased body height
Small stature

[ more ]

Symphalangism affecting the phalanges of the hand
Fused finger bones of the hand
5%-29% of people have these symptoms
Deep philtrum
Hip dislocation
Dislocated hips
Dislocation of hip

[ more ]

Increased size of skull
Large head
Large head circumference

[ more ]

Mandibular prognathia
Big lower jaw
Increased projection of lower jaw
Increased size of lower jaw
Large lower jaw
Prominent chin
Prominent lower jaw

[ more ]

Drooping upper eyelid
Tall chin
Increased height of chin
Long chin

[ more ]

Percent of people who have these symptoms is not available through HPO
Arthrogryposis multiplex congenita
Autosomal dominant inheritance
Cutaneous syndactyly of toes
Webbed skin of toes
Distal arthrogryposis
Poor swallowing
Swallowing difficulties
Swallowing difficulty

[ more ]

Facial asymmetry
Asymmetry of face
Crooked face
Unsymmetrical face

[ more ]

Feeding difficulties
Feeding problems
Poor feeding

[ more ]

Hammer toe

[ more ]

Metatarsus adductus
Front half of foot turns inward
Little lower jaw
Small jaw
Small lower jaw

[ more ]

Talipes equinovarus
Club feet
Club foot

[ more ]



There is no one treatment for trismus-pseudocamptodactyly (TPS), however, there are various strategies that can be used to manage symptoms. Physical and/or occupational therapy may be helpful for individuals experiencing difficulties with walking and hand movement. Surgery may be performed to correct certain musculoskeletal symptoms.[4] There have been reported cases of improvement of mouth mobility following surgery and physical therapy.[1][2][5][6]


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

    Learn more

    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

    • 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

      • 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 Trismus-pseudocamptodactyly syndrome. Click on the link to view a sample search on this topic.


        1. Carlos R, Contreras E, Cabrera J. Trismus-pseudocamptodactyly syndrome (Hecht-Beals' syndrome): case report and literature review. Oral Dis. 2005 May; https://www.ncbi.nlm.nih.gov/pubmed/15888111.
        2. Lefaivre JF, Aitchison MJ. Surgical correction of trismus in a child with Hecht syndrome. Ann Plast Surg. 2003 Mar; https://www.ncbi.nlm.nih.gov/pubmed/12800911.
        3. Victor A. McKusick. ARTHROGRYPOSIS, DISTAL, TYPE 7; DA7. In: Marla J. F. O'Neill. OMIM. 2/26/2013; https://www.omim.org/entry/158300.
        4. Trismus Pseudocamptodactyly Syndrome. NORD. 2003; https://rarediseases.org/rare-diseases/trismus-pseudocamptodactyly-syndrome/. Accessed 7/21/2016.
        5. Gasparini G, Boniello R, Moro A, Zampino G, Pelo S. Trismus-pseudocamptodactyly syndrome: case report ten years after. Eur J Paediatr Dent. 2008 Dec; https://www.ncbi.nlm.nih.gov/pubmed/19072009.
        6. Balkin, Daniel M. MD, PhD; Chen, Isaac DDS; Oberoi, Snehlata DDS, MS; Pomerantz, Jason H. MD. Bilateral Coronoidectomy by Craniofacial Approach for Hecht Syndrome-Related Trismus. Journal of Craniofacial Surgery. September 2015; 26(6):1954-1956. https://www.ncbi.nlm.nih.gov/pubmed/26335328.

        Rare Hematology News