Trismus Pseudocamptodactyly Syndrome

National Organization for Rare Disorders, Inc.

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It is possible that the main title of the report Trismus Pseudocamptodactyly Syndrome is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.


  • Camptodactyly-Limited Jaw Excursion
  • Hecht Syndrome
  • Mouth, Inability To Open Completely, And Short Finger-Flexor Tendons
  • Dutch-Kennedy Syndrome

Disorder Subdivisions

  • None

General Discussion

Trismus-Pseudocamptodactyly Syndrome is a very rare inherited disorder characterized by the inability to completely open the mouth (trismus), causing difficulty with chewing (mastication) and/or the presence of abnormally short muscle-tendon units in the fingers, causing the fingers to curve or bend (camptodactyly) when the hand is bent back at the wrist (dorsiflexion). Because the fingers are not permanently bent or curved, this particular finding is termed "pseudocamptodactyly" (pseudo meaning false). In addition, the muscle-tendon units of the forearms and/or the legs may also be abnormally short, resulting in limited movements and various deformities of the feet. Individuals with this disorder are slightly shorter than would otherwise be expected (mild short stature). The severity of these physical findings varies from individual to individual. Trismus-Pseudocamptodactyly Syndrome is thought to be inherited as an autosomal dominant trait.


Trismus-Pseudocamptodactyly Syndrome is a very rare inherited disorder characterized the inability to fully open the mouth (trismus), often resulting in problems with chewing (mastication). Although this limitation is one of the significant findings associated with this disorder, it may be quite subtle in some affected individuals. In those whom this abnormality is severe, limited and/or impaired chewing (mastication) ability may cause difficulties with eating and proper digestion.

Other major physical findings associated with Trismus-Pseudocamptodactyly Syndrome involve the fibrous cords that connect muscles to bones (tendons). The tendons work in concert with the respective muscles (muscle-tendon unit) and bones to produce movement of various parts of the body. If tendons are unusually short, certain physical abnormalities may result. In Trismus-Pseudocamptodactyly Syndrome, the muscle-tendon units in the fingers are unusually short, resulting in curved or bent fingers (camptodactyly) when the hand is bent backward at the wrist (dorsiflexion). However, if the hand is bent forward at the wrist (volar flexion), the fingers can then be completely extended. Because the fingers are not permanently fixed in the curved or bent position, this particular abnormality may properly be called "pseudocamptodactyly" (pseudo meaning false).

In addition, individuals with this syndrome have shortened muscle-tendon units in the forearms and legs, the latter possibly resulting in various foot deformities. These may include a permanent flexing of the toe or toes (hammer or claw toes), abnormal inward bending of the foot (clubfoot or talipes), flatfoot (pes planus), and/or pigeon-toe (metatarsus varus). In some cases, shortened muscles and tendons may result in an unusual tilt of the pelvis and/or an abnormal positioning or slight twist of the head (mild torticollis). In addition, affected individuals may exhibit difficulty in manual dexterity and walking (locomotion) due to shortened muscle-tendon units and associated abnormalities.

In some cases, individuals with Trismus-Pseudocamptodactyly Syndrome exhibit additional physical abnormalities. For example, they may be slightly shorter than would otherwise be expected. It is important to note that the severity of many of the physical findings associated with this disorder may vary greatly from individual to individual.


Trismus-Pseudocamptodactyly Syndrome is thought to be inherited as an autosomal dominant trait. Genetic diseases are determined by two genes, one received from the father and one from the mother.

Dominant genetic disorders occur when only a single copy of an abnormal gene is necessary for the appearance of the disease. The abnormal gene can be inherited from either parent, or can be the result of a new mutation (gene change) in the affected individual. The risk of passing the abnormal gene from affected parent to offspring is 50% for each pregnancy regardless of the sex of the resulting child.

Affected Populations

Trismus-Pseudocamptodactyly Syndrome is a very rare inherited disorder that, in theory, affects males and females in equal numbers. However, for unexplained reasons, in reported cases females are affected twice as often as males (F2:M1). Approximately 60 cases have been reported in the medical literature. Of those cases, many have been traced to a Dutch female who came to the United States and settled in Tennessee during the latter half of the eighteenth century. In addition, other reported cases have included five affected individuals in three generations of one Japanese family, six affected members of a German family, and affected individuals of families (kindreds) within the Netherlands, Canada, and, as mentioned above, the United States. The disorder was first described in the medical literature in 1969.

Many of the symptoms of Trismus-Pseudocamptodactyly Syndrome are manifested during infancy. As an affected child ages, abnormalities associated with shortened muscle-tendons units (e.g., difficulty in manual dexterity) may become apparent.

Standard Therapies


Trismus-Pseudocamptodactyly Syndrome may be diagnosed during infancy, based upon a thorough clinical evaluation, characteristic physical findings, and/or a variety of specialized tests, including X-rays studies.

The treatment of this disorder is directed toward the specific symptoms exhibited in each individual. Treatment may require the efforts of a team of specialists who work together to systematically and comprehensively plan an affected child's treatment. Such specialists may include pediatricians, those who diagnose and treat skeletal disorders (orthopedists), orthopedic surgeons, dentists, anesthesiologists, physicians who specialize in disorders of the digestive tract (gastroenterologists), nutritionists, physical and occupational therapists, and/or other health care professionals.


Specific therapies for the treatment of this disorder are symptomatic and supportive. For example, in some cases, various orthopedic techniques and/or surgery may be performed to treat and/or correct certain musculoskeletal abnormalities associated with Trismus-Pseudocamptodactyly Syndrome.

In addition, physical and/or occupational therapy may be beneficial to those individuals who experience difficulties with walking (locomotion) and manual dexterity.

Genetic counseling will also be of benefit for affected individuals and their families.

Investigational Therapies

Information on current clinical trials is posted on the Internet at All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.

For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:

Tollfree: (800) 411-1222

TTY: (866) 411-1010


For information about clinical trials sponsored by private sources, contact:



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