Larsen Syndrome Health Article

Diagnosis

Larsen syndrome should be suspected in any baby having multiple joint dislocations at birth. As of 2001, there is no genetic test to confirm the diagnosis and, thus, diagnosis must be based on clinical and x ray findings. Babies suspected to have the condition warrant a complete evaluation by a medical geneticist (a physician specializing in genetic syndromes).

Larsen syndrome is sometimes misdiagnosed as another condition called arthrogryposis, which involves multiple joint contractions. Larsen syndrome can be distinguished from this and other syndromes involving joint dislocations or contractions because of the unusual constellation of features found in the face and hands. Extra bones of the wrist, often seen in Larsen syndrome, are extremely rare in other syndromes.

Some people have very mild symptoms and may not have joint dislocations or other problems at birth. The diagnosis can be missed in these people unless they are carefully evaluated.

A person with dominantly inherited Larsen syndrome has a 50% chance with each pregnancy of having a child with the same disorder. Genetic counseling can help couples sort out their options for parenthood. Some couples would choose to adopt rather than take the chance of an affected child, others would go ahead with a pregnancy, and others would choose to have prenatal diagnosis. The only form of prenatal diagnosis available to date is ultrasound.

Fetal ultrasound performed by a specialist at 18-20 weeks of pregnancy can sometimes reveal signs of Larsen syndrome. Knee dislocations and hyperextension, club feet, fixed flexion of elbows, wrists, and fingers, and some of the characteristic facial features can sometimes be noted by ultrasound in affected fetuses. Physical findings from ultrasound can suggest but do not confirm the diagnosis of Larsen syndrome in a fetus.

Treatment and management

Treatment will vary according to the symptoms of a particular child. Joint problems require long-term orthopedic care. Dislocations, clubfeet, and joint contractures are treated with intensive physical therapy, splints, casting, and/or surgery. Physical therapy is also important after joint surgery to build up muscles around the joint and preserve joint stability. Occupational therapy may be helpful for children with wrist and finger contractures.

Respiratory problems at birth may necessitate oxygen or assistive breathing devices. If not alleviated by medication or special feeding techniques, eating and swallowing problems may require tube feeding. Heart problems, cleft palate, and cataracts often warrant surgical correction. Special care is needed if laxity of the trachea is present because of an increased risk for respiratory problems during and after surgery.

People with chronic pain associated with hypermobile joints often can be helped by techniques taught in a pain management clinic.

Magnetic resonance imaging (MRI) of the neck is recommended in childhood to screen for cervical vertebral problems. Early diagnosis and surgical stabilization of the spine can help patients avoid paralysis and death from spinal cord compression. Scoliosis is usually treated by bracing, or by a surgically placed metal rod. Artificial hip and knee replacements may be needed in early-to-mid adulthood because of degeneration of unstable joints.

Regular medical examinations are crucial to assess the condition of the bones, joints, spine, heart, and eyes. Hearing should be evaluated on a periodic basis, especially in children, because of the potential for conductive hearing loss. Ophthalmologic examinations are recommended periodically to screen for cataracts.

Prognosis

The effects of the syndrome vary markedly from person to person. Therefore, prognosis is based on the findings in a given individual. The usual causes of early death are either severe respiratory problems or compression of the cervical spine from vertebral instability.

If careful and consistent orthopedic treatment is initiated early, prognosis can be good, with a normal life span. Weak and unstable joints and limited range of motion from contractures may cause walking difficulties and restrict other physical activities. Contact sports and heavy lifting should be avoided as anything that puts extra strain or pressure on the joints can cause harm. Swimming is a good activity because it helps strengthen muscles without joint strain.

PERIODICALS

Becker, R., et al. "Clinical Variability of Larsen Syndrome: Diagnosis in a Father after Sonographic Detection of a Severely Affected Fetus." Clinical Genetics 57 (2000): 148-150.

Tongsong, T., et al. "Prenatal Sonographic Diagnosis of Larsen Syndrome." Journal of Ultrasound Medicine 19 (2000): 419-421.

ORGANIZATIONS

Arthritis Foundation. 1330 West Peachtree St., Atlanta, GA 30309. (800) 283-7800 or (404)965-7537. <http://www.arthritis.org>.

Scoliosis Research Society. 6300 N. River Rd., Ste 727, Rosemont, IL 60018-4226. (847)698-1627. Fax: (847) 823-0536. Goulding@aaos.org. <http://www.srs.org/>.

WEBSITES

Hypermobility Syndrome Association. <http://www.hypermobility.org/>.

Larsen Syndrome Resource Page. <http://www.stormloader.com/nita/ls.html>.

Barbara J. Pettersen