Handbook of Genetic Counseling/Ehlers-Danlos Syndrome-3

Ehlers Danlos Syndrome

What Is It?

 * A connective tissue disorder involving their skin, joints, muscles, ligaments, and certain organs. (NOTE: nomenclature has changed over the years to reflect the type of EDS. For example, Type I and II have been combined to be Classic Type. Throughout the following information, you will see both the numerical and names used.)

What Causes It?

 * Mutations in the genes that produce collagen or the enzymes that help maintain the collagen.

What Is the Prevalence?

 * 1/5000-1/10000

What Are the Manifestations?

 * Skin: Hyper-extensibility of the skin, fragile skin that bruises and tears easily, severe scarring
 * Joints: Hyper-mobility of joints, loose joints that may dislocate easily with subluxation (space between them). There may be hernias and there are usually molluscoid pseudotumors (calcified hematomas) over areas like elbows and knees.
 * Cardiac: mitral valve prolapse, and aortic dysfunction (1/4 of Type I&II)
 * Other: dental problems, small teeth, short stature
 * Also, depending on the type of EDS, there can be a variety of manifestations:
 * Vascular Type IV = arterial/intestinal/uterine fragility and rupture (as a result, life expectancy is around 50)
 * Kyphoscoliosis Type VI = scoliosis at birth and fragile sclera (the white of the eye- often looks blue)
 * Arthrochalasia Type VIIB= poor muscle tone

Depends on the type of EDS

 * Type I & Type II-Classic, Type III, Type IV-vascular, Type VIII = Autosomal Dominant
 * Type VI, Type X, Type VI-kyphoscoliosis = Autosomal Recessive
 * Type V, Type IX = X-linked recessive
 * Pregnant women who have EDS are at an increased risk for having premature babies. Additionally, there may be an increase in bruising during pregnancy. A woman who has Type IV is at extreme risk when pregnant because of the risk of uterine rupture and maternal death is possible.

Management

 * Possible bracing for joint stability if needed.
 * The most important aspect is to avoid strenuous activities that would put stress on the joints.
 * Children should not be encouraged to maintain strange positions with their bodies as they may cause degeneration of their joints later on.

How Is It Diagnosed?

 * In most cases the diagnosis is clinical only. There are a few types that can be diagnosed molecularly.
 * Type I & II - Classic Type has been found to be liked to mutations in the collagen V, alpha1 and alpha 2 gene. These changes can be diagnosed with a skin biopsy.
 * Type IV-Vascular Type is caused by a structural defect in the proal chain of collagen type III. A skin biopsy will diagnose it.
 * Type VI - Kyphoscoliosis can be diagnosed by a urine test and is a result of a deficiency of lysyl hydroxylase (a collagen-modifying enzyme).
 * Type VIIB-Arthrochalasia Type can be diagnosed through skin biopsy. It is caused by incorrect processing of the amnio terminal end of the proa1(IA) or proa2 (IA) chains of collagen type I.
 * Type VIIC - Dermatosparaxis can be diagnosed through skin biopsy. It is caused by a deficiency of procollagen I on the N-terminal.

Where Can Parents Get More Information?

 * Ehlers-Danlos National Foundation (EDNF)
 * 6399 Wilshire Blvd Suite 510
 * Los Angeles, CA 90048
 * (213) 651-1366
 * http://www.ednf.org

Resources

 * The Ehlers-Danlos National Foundation: http://www.ednf.org
 * Beighton, Peter. McKusick's Heritable Disorders of Connective Tissue 5th Ed. Mosby 1992, Chap. 6.
 * OMIM
 * Smith's
 * Wheeless' Textbook of orthopedics: http://www.medmedia.com/med.htm