Type 2 Collagen Disorders/Spondyloepiphyseal Dysplasia

Wikis > Orthopaedics > Bone and Joint/Skeletal Dysplasia/Osteochrondroplasia > Type 2 Collagen Disorders/Spondyloepiphyseal Dysplasia

Type 2 Collagen Disorders/Type 2 Collagenopathies/Spondyloepiphyseal Dysplasia:
Type 2 collagen is a major structural component of cartilage, so different mutations of gene coding for type 2 collagen  different chondrodysplasia’s.

Spondyloepiphyseal dysplasia congenital (SED):
• disproportionately short trunk dwarfism- autosomal
• evident at birth- affect 1 in 3-4 million
• abnormality in aipha-1(II) chains in the triple helix fibril of the type 2 collagen
• mild facial flattening; short neck; barrel shaped chest; cleft pallet is common
• hands and feet usually normal looking or equinovarus

Kniest type spondyloepiphyseal dysplasia:
• characterised by short statues; short trunk; scoliosis; cleft palate; hearing loss; flat nasal bridge
• formation of triple helix of collagen is severely disrupted

Kniest Syndrome:
• enlarged stiff joints characteristic
• defect is in type 2 collagen (dominant protein in cartilage)- most are a mutation on COL2A1 gene
• Facial- prominent eyes and forehead, depressed midface; cleft palete

Stickler syndrome/Hereditary arthro-ophthalmopathy:
• autosomal dominant mutation in collagen type 2 gene
• myopia, vitreoretinal degeneration, retinal detachment, premature osteoarthritis

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