Ehlers-Danlos-like syndrome due to tenascin-X deficiency
Type of disease: Rare conditions
Ehlers-Danlos syndrome (EDS) is a rare tissue disorder that has six specific types. EDS affects a person’s connective tissue, which separates, connects and supports different organs in the body. People with EDS usually cannot make enough normal collagen, a connective tissue protein.
Ehlers-Danlos syndrome, tenascin-X deficient type (TNX-deficient EDS) is a very rare form of EDS but has many of the same symptoms as classical type EDS. These symptoms include easy bruising, abnormally stretchy skin (hyperextensible), very loose joints with an abnormally large range of movement (hypermobility), and joints that dislocate/ subluxate easily. However, unlike classical type, which is known for slow wound healing and “cigarette paper” (atrophic) scars, people with TNX-deficient EDS experience normal wound healing and scarring. Other symptoms may include velvety skin, joint pain, and muscle weakness. Some cases have included mitral valve prolapse, which affects blood flow between the chambers of the heart.
There is no cure for TNX-deficient EDS; it is a life-long condition that requires close monitoring. Management includes physical therapy and lifestyle changes. Echocardiograms (ultrasound scans of the heart) are also recommended to check the heart valves.
TNX-deficient EDS is passed through families in an autosomal recessive manner, meaning that a person needs to inherit two copies of the changed gene to develop the disorder. It is caused by mutations in the TNXB gene, which contains the instructions needed to make the protein Tenascin-X. Tenascin-X binds collagen together in the body and is important in making connective tissues.
If you or your child has been diagnosed with TNX-deficient EDS, talk to your doctor about the most current treatment options. A genetic counselor can be helpful to discuss inheritance and risks to other family members. Support groups are also available for more resources and information.