Kyphoscoliotic Ehlers-Danlos syndrome (kEDS) is one of 13 types of EDS, a group of connective tissue disorders. kEDS is characterized by kyphoscoliosis, a sideways curvature of the spine in combination with a hunched back.
What causes kEDS?
kEDS is caused by mutations in the PLOD1 gene, and in rarer cases, in the FKBP14 gene. The PLOD1 gene provides instructions to build an enzyme called lysyl hydroxylase 1. This enzyme modifies certain amino acids — a protein’s building blocks — of collagen, which is essential for the formation of collagen cross-links. Collagen is the main protein in the body’s connective tissue, providing strength and support to different tissues and organs. Without proper cross-linking between collagen proteins, the connective tissue becomes weak, leading to the symptoms of kEDS.
The FKBP14 gene provides instructions to build a protein that helps other proteins to fold properly. Correct folding is essential for a protein’s function. It is not understood how mutations in the FKBP14 gene cause kEDS.
How is kEDS inherited?
Every individual carries two copies of the PLOD1 gene, one from the mother and one from the father. The condition only manifests when both copies of the gene are mutated. If both parents have one mutated PLOD1 gene copy, there is a 25% chance for the child to inherit both mutated copies — one from each parent — and develop kEDS. The chance of inheriting one mutated PLOD1 gene copy is 50%, in which case no EDS symptoms occur. Individuals with one mutated gene copy are called carriers, and can potentially pass the disease along to their own children. This inheritance pattern is known as autosomal recessive.
What are the symptoms of kEDS?
Common symptoms of kEDS include:
- joint hypermobility
- hyperextensible and fragile skin that bruises easily
- atypical scarring of the skin
- progressive kyphoscoliosis that is present at birth or appears during the first year of life
- abnormal gait
- delayed motor development
- hypotonia, or low muscle tone at birth
- visual impairment
- fragile arteries that are prone to tears
How is kEDS diagnosed?
The diagnostic process typically includes an assessment of the patient’s medical history, physical exams, and a detailed analysis of the symptoms.
Urine and skin samples are analyzed to detect deficiencies of enzymes that are involved in collagen cross-linking. A genetic test to detect mutations in the PLOD1 gene is usually performed to confirm the diagnosis.
How is kEDS treated?
As with other types of EDS, there currently is no cure for kEDS. Treatments focus on the management of the symptoms, and on preventing serious complications.
Physiotherapy can help to improve joint stability. It can also reduce hypotonia and be beneficial for motor development.
Splints and braces can provide support to the joints. In cases of severe kyphoscoliosis, surgery might be necessary.
Last updated: Nov. 06, 2019
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