What are the other Names for this Condition? (Also known as/Synonyms)
- X-Linked SED
- X-Linked Spondyloepiphyseal Dysplasia
What is X-Linked Spondyloepiphyseal Dysplasia Tarda? (Definition/Background Information)
- X-Linked Spondyloepiphyseal Dysplasia Tarda is an inherited skeletal disorder that affects males only
- Physical characteristics include moderate short-stature (dwarfism); moderate to severe spinal deformities; barrel-chest; disproportionately short trunk and neck; disproportionately long arms, and premature osteoarthritis, especially in the hip joints
- Final male adult height ranges from 4 feet 10 inches to 5 feet 6 inches. Other skeletal features of this condition include decreased mobility of the elbow and hip joints, arthritis, and abnormalities of the hip joint which causes the upper leg bones to turn inward
- X-Linked Spondyloepiphyseal Dysplasia Tarda is caused by mutations in the TRAPPC2 gene and is inherited in an X-linked recessive pattern
(Source: X-Linked Spondyloepiphyseal Dysplasia Tarda; Genetic and Rare Disease Information Center (GARD) of National Center for Advancing Translational Science (NCATS), USA.)
Who gets X-Linked Spondyloepiphyseal Dysplasia Tarda? (Age and Sex Distribution)
- X-Linked Spondyloepiphyseal Dysplasia Tarda is a rare congenital disorder, occurring at a frequency of 1:150,000-200,000
- The presentation of symptoms generally occurs when a child is between 6-10 years of age
- The condition almost only affects males
- Worldwide, individuals of all racial and ethnic groups may be affected
What are the Risk Factors for X-Linked Spondyloepiphyseal Dysplasia Tarda? (Predisposing Factors)
- A positive family history may be an important risk factor, since X-Linked Spondyloepiphyseal Dysplasia Tarda can be inherited
- Currently, no other risk factors have been clearly identified for the disorder
It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.
Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.
What are the Causes of X-Linked Spondyloepiphyseal Dysplasia Tarda? (Etiology)
- X-Linked Spondyloepiphyseal Dysplasia is caused by mutations in the TRAPPC2 gene (sometimes called the SEDL gene), which is located on the X chromosome
- The TRAPPC2 gene provides instructions for producing a protein called sedlin. The function of this protein is unclear. Researchers believe that sedlin is part of a larger protein complex, which helps transport proteins between various cell organelles. Mutations in TRAPPC2 affect how the sedlin protein is made, which ultimately affects bone growth
- This condition is inherited in an X-linked recessive pattern. A condition is considered X-linked if the mutated gene that causes the disorder is located on the X chromosome, one of the two sex chromosomes. In X-linked recessive inheritance, a female with one mutated copy of the gene in each cell is called a carrier. She can pass on the altered gene, but usually does not experience signs and symptoms of the disorder. However, mild symptoms of osteoarthritis have been reported in female carriers of X-Linked Spondyloepiphyseal Dysplasia Tarda
(Source: X-Linked Spondyloepiphyseal Dysplasia Tarda; Genetic and Rare Disease Information Center (GARD) of National Center for Advancing Translational Science (NCATS), USA.)
What are the Signs and Symptoms of X-Linked Spondyloepiphyseal Dysplasia Tarda?
The signs and symptoms of X-Linked Spondyloepiphyseal Dysplasia Tarda may vary among affected individuals in type and severity, and may include:
- Arthralgia
- Barrel-shaped chest
- Coxa vara
- Disproportionate short-trunk short stature
- Hip osteoarthritis
- Hump-shaped mound of bone in central and posterior portions of vertebral endplate
- Hypoplasia of the capital femoral epiphysis
- Hypoplastic iliac wing
- Irregular epiphyses
- Kyphosis
- Limitation of joint mobility
- Lumbar hyperlordosis
- Opacification of the corneal stroma
- Platyspondyly
- Shield chest
- Short femoral neck
- Short neck
- Spondyloepiphyseal dysplasia
(Source: X-Linked Spondyloepiphyseal Dysplasia Tarda; Genetic and Rare Disease Information Center (GARD) of National Center for Advancing Translational Science (NCATS), USA.)
How is X-Linked Spondyloepiphyseal Dysplasia Tarda Diagnosed?
X-Linked Spondyloepiphyseal Dysplasia Tarda is diagnosed on the basis of the following information:
- Complete physical examination
- Thorough medical history evaluation
- Assessment of signs and symptoms
- Laboratory tests
- Imaging studies
- Biopsy studies, if necessary
Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.
What are the possible Complications of X-Linked Spondyloepiphyseal Dysplasia Tarda?
The complications of X-Linked Spondyloepiphyseal Dysplasia Tarda may include:
- Short stature, which may lead to low self-esteem
- Severe pain (generally in hips, knees, and shoulders) due to osteoarthritis
- Back pain due to kyphosis or scoliosis
- Crowding of organs in the chest cavity due to scoliosis, which may cause heart and lung abnormalities
Complications may occur with or without treatment, and in some cases, due to treatment also.
How is X-Linked Spondyloepiphyseal Dysplasia Tarda Treated?
There is no cure for X-Linked Spondyloepiphyseal Dysplasia Tarda, since it is a genetic condition. The treatment is usually given to manage the signs and symptoms and any complication that develops.
- Many affected individuals require joint replacement surgery (hip, knee, shoulder) or spine surgery (correction of scoliosis or kyphosis). Hip replacement is often required as early as 30 years of age
- Chronic pain management is standard and often required before or after surgery
- Affected individuals should be regularly followed by a professional familiar with this condition for the development of joint pain and scoliosis
(Source: X-Linked Spondyloepiphyseal Dysplasia Tarda; Genetic and Rare Disease Information Center (GARD) of National Center for Advancing Translational Science (NCATS), USA.)
How can X-Linked Spondyloepiphyseal Dysplasia Tarda be Prevented?
X-Linked Spondyloepiphyseal Dysplasia Tarda may not be preventable, since it is a genetic disorder.
- Genetic testing of the expecting parents (and related family members) and prenatal diagnosis (molecular testing of the fetus during pregnancy) may help in understanding the risks better during pregnancy
- If there is a family history of the condition, then genetic counseling will help assess risks, before planning for a child
- Avoiding strenuous sporting or other activities may help prevent wear and tear on stress-bearing and weight bearing joints. Such activities may worsen the condition
- Active research is currently being performed to explore the possibilities for treatment and prevention of inherited and acquired genetic disorders
- Regular medical screening at periodic intervals with tests and physical examinations are recommended
What is the Prognosis of X-Linked Spondyloepiphyseal Dysplasia Tarda? (Outcomes/Resolutions)
The prognosis of X-Linked Spondyloepiphyseal Dysplasia Tarda is dependent upon the severity of the signs and symptoms and associated complications, if any.
- However, affected males are reported to have a normal lifespan and intelligence
- Additionally, no delay is reported in achieving cognitive or motor milestones
- The pain associated with osteoarthritis may worsen with age
Additional and Relevant Useful Information for X-Linked Spondyloepiphyseal Dysplasia Tarda:
The following DoveMed website link is a useful resource for additional information:
http://www.dovemed.com/diseases-conditions/rare-disorders/
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