Fibrillar collagenopathies

Fibrillar collagenopathies is a mechanism class of 4 diseases in this volume that share a defective fibrillar collagen of the extracellular matrix, acting by dominant-negative or haploinsufficiency. This chapter links each member to its own canonical page rather than restating it; the graded burden values live on those pages and in the framework.

The shared mechanism

The affected collagen is type I in osteogenesis imperfecta (bone matrix), type II in achondrogenesis type II (cartilage), type III in vascular Ehlers-Danlos syndrome (vessel and hollow-organ walls), and type V in classic Ehlers-Danlos syndrome (regulation of dermal type I fibrillogenesis). The shared lesion is a structural-matrix protein defect acting through a dominant-negative poisoned triple helix or through haploinsufficiency; three of the four are read by the carried morphogenesis engine as perturbations of the same connective-tissue patterning baseline (the length band λ = √(D·τ)).

Member diseases (each on its own page)

• #8Osteogenesis imperfectaskeletal · COL1A1, COL1A2 · residual burden rank 8/23
• #1Achondrogenesis type IIskeletal · COL2A1 · residual burden rank 1/23
• —Ehlers-Danlos syndrome, type 4connective_tissue · COL3A1 · not placed (insufficient axis coverage)
• —Ehlers-Danlos syndrome, classic type, 1connective_tissue · COL5A1 · not placed (insufficient axis coverage)

This chapter is a cross-reference: the burden order and all graded values live on the individual disease pages and in the framework (§1). Membership is read from the curated dossiers’ gene and mechanism fields, so the class list is reproducible, not hand-picked.