_:vb50942433 . _:vb50942433 "url:https://www.ncbi.nlm.nih.gov/pubmed/15744043"^^ . _:vb50942433 . _:vb50942433 "An amelogenesis imperfecta that has_material_basis_in homozygous mutation in the matrix metalloproteinase-20 gene (MMP20)."^^ . _:vb50942433 . _:vb50942433 . _:vb50942433 .