Can you explain why there are "crossovers" of characteristics among the different types of eds?

Collagen. Eds has many different types. In most of its forms, the defect involves some aspect of collagen. Collagen is one of the basic building blocks of connective tissue which is found in all organs, joints and blood vessels. Depending on the exact type of genetic defect, and becasue collagen is found everywhere, there is cross-over in the types of eds with similar manifestations.
Collagen. The abnormality of collagen is different with the different types of eds but the key is collagen. The overlapping charters tics are tied to the tissues containing the different types of collagen. Most body parts contain more than 1 type of ollagen and will be affected by mutations of several different types. The severity of problems depends on the collagen type and severity of defect.