Arthrochalasia Ehlers-Danlos syndrome (aEDS) is a type of EDS characterized by frequent hip dislocations in addition to the more common EDS-associated symptoms of hypermobile joints. Skin-related symptoms are uncommon in this form of the disease.
Other names of aEDS include arthrochalasis multiplex congenita and Ehlers-Danlos syndrome type 7A (EDS7A).
What causes aEDS?
EDS is a result of insufficient levels or the improper functioning of collagen, the primary building block of connective tissue. Several types of collagen exist. Type 1 collagen is the most abundant in the body.
There are multiple types of mutations affecting collagen differently and causing 13 types of EDS. aEDS is caused by mutations in the COL1A1 or the COL1A2 genes that carry instructions to make the amino acid chains that make type 1 collagen. These mutations disrupt the normal structure of collagen and affect its function. As a result, tissues rich in type 1 collagen, including the connective tissues, are weakened, causing the symptoms of aEDS.
How is aEDS inherited?
Both COL1A1 and COL1A2 genes are located on chromosomes that do not determine gender (also known as autosomes). The COL1A1 gene is located on chromosome 17, while COL1A2 is located on chromosome 7.
There are two copies of every gene present on the autosomes, one from each parent. aEDS is inherited in an autosomal dominant manner, which means that only one copy of the gene needs to be mutated for the disease to develop. So, there is a 50% chance for a person with aEDS to pass the disease to their child.
In some cases, aEDS-causing mutations can occur in an individual even when their parents do not carry the genetic mutation. Such first occurrence of genetic changes is called a de novo mutation.
What are the symptoms of aEDS?
The severity and incidence of aEDS symptoms vary among patients. Some reported symptoms include:
- hip dislocation at birth
- overly flexible joints
- low muscle tone (hypotonia)
- low bone density (osteopenia)
- bent spine (kyphosis or scoliosis)
- rare instances of fragile, stretchy skin
How is aEDS diagnosed?
A doctor may suspect EDS based on a patient’s symptoms, family medical history, and physical exams.
How is aEDS treated?
Treatments of EDS mostly focus on alleviating symptoms and preventing further complications.
In severe cases of hip dislocation and curved spine, surgery may be required to correct the defect.
Last updated: Oct. 30, 2019
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