Trichorhinophalangeal Syndrome

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Trichorhinophalangeal syndrome

Definition

Trichorhinophalangeal syndrome, or Langer-Giedion syndrome (LGS), is characterized by skeletal abnormalities and dysmorphic (distinctive) facial features. Most people with LGS also have mental retardation.

Description

LGS affects mostly the skeletal system and facial structure. Since the features include abnormalities in the hair (tricho), nose shape (rhino), and fingers and toes (phalangeal), the technical name for LGS is trichorhinophalangeal syndrome.

Genetic profile

LGS is not usually passed through generations in a family. However, the condition is considered a contiguous-gene syndrome. This means that it is caused by the loss of functional copies of two genes near each other on chromosome 8. Research suggests that another gene may be involved. Genetic counseling is suggested for anyone considering pregnancy who has a relative with this condition.

Demographics

About 50 cases of Langer-Giedion syndrome have been reported in the literature. Males are affected three times more often than females.

Signs and symptoms

Craniofacial features associated with Langer-Giedion syndrome include a bulbous, pear-shaped nose; a small jaw; a thin upper lip; and large ears. The hair is usually sparse, and the head is small in 60% of individuals with LGS. Mild to severe mental retardation is present in 70% of people; it often affects speech more than other skills.

Skeletal features include exostoses—spiny growths on the bone—which occur before age five and usually increase in number until the skeleton matures. Compression of nerves or blood vessels, asymmetric limb growth, and limitation of movement are problems that can result from the exostoses. Scoliosis—a curvature of the spine—is found in some people, as well as thin ribs. Short stature is often seen as a result of epiphyses—cone-shaped bone ends. Longitudinal bone growth appears to be slowed. Short and/or curved fingers are common. Loose skin often occurs, but that tends to improve with age.

Features of LGS that are less commonly seen include loose joints and low muscle tone. Others are wandering eye (exotropia), droopy eyelid, widely spaced eyes, fractures in the bones, birthmarks that increase with age, hearing loss, heart or genito-urinary abnormalities, and webbing of the fingers.

Diagnosis

The criteria for diagnosis of LGS are a bulbous, pear-shaped nose, and epiphyses and exostoses. These signs are probably all related to abnormal bone growth, but researchers do not yet understand the link to mental retardation and hair abnormalities. The distinctive facial features may be recognized at birth. Changes in the epiphyses are recognizable through x ray by age three, and exostoses are visible by age five. Chromosome analysis will likely reveal an abnormality in a certain region of chromosome 8.

There are no reports of prenatal diagnosis of this condition. To provide accurate genetic counseling regarding prognosis and risk of recurrence, it is important to distinguish this condition from others that are similar to it, such as tricho-rhino-phalangeal syndrome, type 1.

Treatment and management

The treatment for LGS is tailored to each person. Exostoses may need to be surgically removed if they are causing problems with nerves or blood vessels. If the two leg lengths are different, corrective shoes may be helpful. Orthopedic devices such as braces or, more rarely, surgery may be indicated in severe cases of skeletal abnormality. Plastic surgery to alter specific features, such as the ears or nose, has been chosen by some people.

The risk of cancer at the site of the exostoses is not known but may be higher.

Special education for mentally retarded individuals is indicated. A focus on speech development may be appropriate.

Prognosis

Langer-Giedion syndrome does not alter life span. Complications from associated abnormalities such as mental retardation, however, can cause problems. Asymmetry of the limbs can interfere with their function and cause pain. Psychological effects due to physical abnormalities may also be experienced.

Resources

BOOKS

Goodman, Richard M., and Robert J. Gorlin. "Langer-Giedion Syndrome." The Malformed Infant and Child. New York: Oxford University Press, 1983.

"Tricho-rhino-phalangeal Syndrome, Type II." Birth Defects Encyclopedia, ed. Mary Louise Buyse. Boston: Blackwell Scientific Publications, 1990.

PERIODICALS

Moroika, D., and Y. Hosaka. "Aesthetic and Plastic Surgery for Trichorhinophalangeal Syndrome." Aesthetic Plastic Surgery 24 (2000): 39-45.

ORGANIZATIONS

Langer-Giedion Syndrome Association. 89 Ingham Ave., Toronto, Ontario M4K 2W8, Canada. (416) 465-3029. [email protected].

National Institute on Deafness and Other Communication Disorders. 31 Center Dr., MSC 2320, Bethesda, MD 20814. (301) 402-0900. [email protected]. <http://www.nidcd.nih.gov>.