Inherited genetic abnormalities that lead to changes in the structure or function of collagen and allied structural proteins describe which syndrome?

• A. Marfan syndrome
• B. Ehlers-Danlos syndrome
• C. Osteogenesis imperfecta
• D. Noonan syndrome

Answer: (B)

The key idea is disorders caused by inherited defects in collagen and related structural proteins, which produce connective tissue fragility. Ehlers-Danlos syndrome is the classic example of this group, arising from mutations that affect collagen synthesis, processing, or structure. This leads to features like hyperextensible skin, hypermobile joints, and fragile tissues that bruise or tear easily, reflecting the widespread impact of defective collagen on tissue integrity.

Osteogenesis imperfecta also involves collagen (type I) and bone fragility, but its primary hallmark is brittle bones rather than the generalized connective-tissue fragility and joint hypermobility emphasized in the description. Marfan syndrome involves fibrillin-1, a different component of the connective tissue network, and Noonan syndrome is a RASopathy with features not centered on collagen defects.