Is an autosomal dominant defect in the
type-III collagen synthesis; now thought to affect approximately 1 in 50,000 to 1 in 200,000.
[20] Most are only diagnosed after rupturing, so it is believed that many more may well go undiagnosed. The vascular type is considered one of the more serious forms of Ehlers–Danlos syndrome because blood vessels and organs are fragile and prone to tearing (rupture). Many patients with EDS type 4 express a characteristic facial appearance (large eyes, small chin, sunken cheeks, thin nose and lips, lobeless ears), have a small stature with a slim build, and typically have thin, pale, translucent skin (veins can usually be seen on the chest and abdomen) with very easy bruising and propensity to develop
ecchymoses (bruising without trauma). Degree of severity depends on the nature of the mutations involved. The current statistics, based largely on those only diagnosed after rupturing, indicate that about one in four people diagnosed with vascular type EDS develop a significant health problem by age 20 and more than 80 percent develop life-threatening complications by age 40.