Abnormal growth plate function in pigs carrying a dominant mutation in type X collagen

Area of Science:

• Genetics
• Biochemistry
• Animal Models

Background:

• Type X collagen (COL10A1) is crucial for endochondral ossification.
• Mutations in COL10A1 are linked to skeletal disorders like Schmid metaphyseal chondrodysplasia (SMCD).
• Dwarfism in domestic pigs (Sus scrofa) presented an opportunity to study collagen-related skeletal abnormalities.

Purpose of the Study:

• To identify the genetic cause of dwarfism in domestic pigs.
• To characterize the resulting skeletal abnormalities.
• To establish the dwarf pig as an animal model for human SMCD.

Main Methods:

• Positional candidate gene analysis to pinpoint the causative mutation.
• Radiological and histological examination of affected pigs.
• Yeast two-hybrid and in vitro assays to assess protein function.

Main Results:

• A dominant mutation, G590R, in the alpha1(X) chain of type X collagen was identified as the cause of dwarfism.
• Dwarf pigs exhibited metaphyseal chondrodysplasia, mirroring human SMCD.
• The mutation impaired collagen type X trimerization and assembly.

Conclusions:

• The identified mutation in pigs provides a genetic and phenotypic parallel to human SMCD.
• Chondrodysplastic dwarf pigs serve as a relevant animal model for studying SMCD.
• This research deepens our understanding of type X collagen function in skeletal development.