Ehlers-Danlos syndrome (EDS) refers to a group of rare genetic disorders that affect the connective tissues, which provide support to the skin, bones, blood vessels, and other organs of the body. EDS formerly was broken down into more than 10 distinct types of the disease but has been consolidated into six categories.
The six categories are arthrochalasia, classic, dermatosparaxis, hypermobility, kyphoscoliosis, and vascular. While other forms of the disease do exist, they are extremely rare and are not considered distinct entities.
Symptoms of EDS may range from mild to severe and life threatening. All types of EDS affect the joints, and many also affect the skin. Almost all forms of the disease are characterized by hypermobility of the joints, which means an abnormally wide range of motion.
The hypermobility and classic forms of EDS are the most common. Other types are extremely rare. There are about 30 known cases of the arthrochalasia type and about 60 of the kyphoscoliosis type. Only about 12 infants are known to have had the dermatosparaxis type.
The prevalence of all types of EDS worldwide is about 1 in 400,000 people. Of people with EDS, the hypermobility type occurs in about 1 in 10,000-15,000 people, while the classic type occurs in about 1 in 20,000-40,000 people. The vascular type, which is extremely rare, occurs in about 1 in 250,000 people with EDS. EDS appears to affect males and females in equal numbers. Some research indicates that EDS may be more common in Caucasians than in other groups.
EDS is caused by mutations or defects in the ADAMTS2, COL1A1, COL1A2, COL3A1, COL5A1, COL5A2, PLOD1, and TNXB genes. Some of these genes provide instructions for making proteins used to make collagen, the primary component of connective tissues. Others provide instructions for making proteins that interact with collagen. The genetic mutations that cause EDS affect the proper structure and function of collagen, which can weaken connective tissues and cause symptoms.
EDS is inherited, or passed down among family members. The pattern of inheritance varies based on the type of EDS. All types of EDS may also occur in people with no family history of the disorder, as the result of a spontaneous genetic mutation in the sperm, egg cells, or developing embryo.
Most people with EDS can live a fairly normal life. People with vascular EDS (type 4) often have a shorter than normal lifespan because of complications ranging from a collapsed lung to severe blood vessel problems. Cognitive function tends to remain unaffected in EDS. There is no cure for EDS. Instead, treatment involves managing symptoms and learning how to protect the joints and prevent injuries.
ADAMTS2 gene, arthrochalasia type, COL1A1 gene, COL1A2 gene, COL3A1 gene, COL5A1 gene, COL5A2 gene, classic type, collagen, dermatosparaxis type, E-D syndrome, EDS, hypermobility type, kyphoscoliosis type, PLOD1 gene, TNXB gene, vascular type.
types of the disease
General: Ehlers-Danlos syndrome (EDS) formerly was broken down into more than 10 distinct types of the disease. However, researchers have recently consolidated the different forms into six categories, which are arthrochalasia, classic, dermatosparaxis, hypermobility, kyphoscoliosis, and vascular. Individual cases may fit into more than one category of disease, and overlap is common.
Arthrochalasia type: Formerly known as type VII EDS, the arthrochalasia type of EDS is inherited as an autosomal dominant trait. Only about 30 cases have been reported. Signs and symptoms of this type include very loose joints and dislocation of both hips that is present at birth; stretchy, fragile skin that is prone to bruising and scarring; early-onset arthritis; and increased risk of bone loss and fracture. People with this type of EDS may have short stature.
Classic type: Formerly known as EDS types I and II, the classic type may be inherited as an autosomal dominant or autosomal recessive trait and is the best described of all the types. This type affects approximately 2-5 in 100,000 people and may be caused by mutations in the COL5A1, COL5A2, COL1A2, or TNXB genes. These genes provide instructions for making components of collagen. When inherited as an autosomal dominant trait, the classic type of EDS appears to be caused by mutations in the COL5A1 or COL5A2 gene. It is estimated that about half of cases of the classic form of the disease are caused by mutations in the COL5A1 gene. Signs and symptoms of this type of EDS include loose joints, which are prone to dislocation and may delay the development of gross motor skills, especially when a child starts to walk; highly elastic, velvety skin; fragile skin that bruises or tears easily; slow and poor wound healing, leading to scarring; noncancerous fibrous growths on pressure areas such as elbows and knees; fatty growths on the shins and forearms; hernias; and heart valve problems, including mitral valve prolapse.
Dermatosparaxis type: Formerly known as type VII EDS, the dermatosparaxis type of EDS is inherited as an autosomal recessive trait. This type of EDS is also particularly rare, with only 10 cases reported in the scientific literature. Signs and symptoms of this type of EDS include extremely fragile and sagging skin; loose joints, which may delay the development of motor skills in children; short stature; delayed closure of the fontanelles, the soft areas at the top of a baby's head; characteristic facial appearance with swollen eyelids and a bluish tinge to the whites of the eyes; umbilical hernia; and short fingers.
Hypermobility type: Formerly known as type III EDS, the hypermobility type may be inherited as an autosomal dominant or recessive trait. This type of EDS affects 1 in 10,000-15,000 people. Signs and symptoms of this subtype include loose, unstable joints; soft, velvety skin; chronic degenerative joint disease; advanced premature osteoarthritis with chronic pain; and heart valve problems, such as mitral valve prolapse. This type may also feature gum disease.
Kyphoscoliosis type: Formerly known as type VI EDS, the kyphoscoliosis type is inherited as an autosomal recessive trait. As another rare form of EDS, only 60 cases of the kyphoscoliosis type have been reported. This type of EDS is associated with progressive abnormal curvature of the spine, which may affect breathing. People with this type of EDS may also have more serious eye problems, including glaucoma (increased pressure in the eye), discoloration of the whites of the eyes, and a detached retina, which is when the retina is pulled away from its normal position in the back of the eye. The retina sends visual images from the eye to the brain through the optic nerve. Individuals with this type of EDS also are at increased risk of rupture of the medium-sized arteries.
Vascular type: Formerly known as type IV EDS, the vascular type is inherited as an autosomal dominant trait. This type of EDS affects approximately 1 in 100,000 people and is the most severe, with past studies having placed life expectancy at around 48 years. The vascular type of EDS is associated with potentially life-threatening ruptures of the blood vessels, lung problems, and internal organ damage. Individuals with this type of EDS may have low body weight and short stature. Surgery can be extremely dangerous for people with this type of EDS.
Other types of EDS: The types of EDS formerly known as types V, VIII, IX, X, and XI are extremely rare and were not included in the updated classification.