The Clinical Presentation of Ehlers-Danlos Syndrome

Elizabeth J. Lawrence, RNC, MSN, NNP


Adv Neonatal Care. 2005;5(6):301-314. 

In This Article

Understanding the Genetics of EDS

Genes exist in pairs and are the blueprints for the development and function of every cell in the body.[2,46] A developing fetus receives one half of each gene pair from each parent, creating a new set of gene pairs that determine the infant's traits. There are 23 pairs of chromosomes: 22 pairs known as autosomes and a pair of chromosomes that determines the sex of an infant.[2]

The classical, hypermobile, vascular, and arthrochalasia types of EDS are inherited in an autosomal dominant manner.[1,7,10,25] Each affected infant has an affected parent. The altered gene is found on an autosome rather than the sex chromosome; therefore, males and females are equally affected.[2] The EDS gene is dominant, requiring only 1 gene to express EDS characteristics.[2,7] If 1 parent has EDS and 1 parent does not, they have a 50% chance of having a child with EDS and 50% chance of having an unaffected child.

Inheritance with the kyphoscoliosis and dermatosparaxis types of EDS is autosomal recessive; therefore, 2 copies of the altered gene must be present for EDS to occur.[1,7,35] Couples who have an affected child have a 25% chance of having another affected child with each subsequent pregnancy.[35,46]

The patterns of inheritance and the type of EDS remain consistent within a family.[2,3,46] A family with classical-type EDS will not develop vascular-type EDS without the introduction of those genes into the family. However, variations in the severity of EDS can occur within a family.

Vascular-type EDS can be identified by mutations in the COL3A1 gene.[1,4,9,29] The COL3A1 gene is 1 of several genes that provide instructions for making the components of collagen. Type III collagen is found in tissues such as the skin, lungs, intestinal walls, and the walls of blood vessels.[29] Currently, there are 320 mutations of the COL3A1 gene identified in vascular EDS.[29]


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