[Mutations of noncollagen genes in osteogenesis imperfecta--implications of the gene products in collagen biosynthesis and pathogenesis of disease].
Recent investigations revealed that the "brittle bone" phenotype in osteogenesis imperfecta (OI) is caused not only by dominant mutations in collagen type I genes, but also by recessively inherited mutations in genes responsible for the post-translational processing of type I procollagen as well as for bone formation. The phenotype of patients with mutations in noncollagen genes overlaps with very severe type III and lethal type II OI caused by mutations in collagen genes. Mutations in genes that encode proteins involved in collagen prolyl 3-hydroxylation (P3H1/CRTAP/CyPB) eliminated Pro986 hydroxylation and caused an increase in modification of collagen helix by prolyl 4-hydroxylase and lysyl hydroxylase. However, the importance of these disturbances in the disease pathomechanism is not known. Loss of complex proteins' function as collagen chaperones may dominate the disease mechanism. The latest findings added to the spectrum of OI-causing and collagen-influencing factors other chaperones (HSP47 and FKBP65) and protein BMP-1, which emphasizes the complexity of collagen folding and secretion as well as their importance in bone formation. Furthermore, mutations in genes encoding transcription factor SP7/Osterix and pigment epithelium-derived factor (PEDF) constitute a novel mechanism for OI, which is independent of changes in biosynthesis and processing of collagen.
Zakład Chemii Medycznej, Uniwersytet Medyczny w Białymstok. angajko@umb.edu.pl
Anna
A
Galicka
D055395:Bone Morphogenetic Protein 1 / Q000235:genetics / Q000378:metabolism; D024042:Collagen Type I / Q000096:biosynthesis* / Q000235:genetics*; D021983:Cyclophilins / Q000235:genetics; D016326:Extracellular Matrix Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D005136:Eye Proteins / Q000235:genetics / Q000378:metabolism; D005808:Genes, Recessive; D006801:Humans; D018832:Molecular Chaperones / Q000378:metabolism; D009154:Mutation; D009414:Nerve Growth Factors / Q000235:genetics / Q000378:metabolism; D016366:Open Reading Frames / Q000235:genetics; D010013:Osteogenesis Imperfecta / Q000235:genetics* / Q000378:metabolism*; D011393:Procollagen-Proline Dioxygenase / Q000235:genetics; D011499:Protein Processing, Post-Translational; D011506:Proteins / Q000378:metabolism*; D015843:Serpins / Q000235:genetics / Q000378:metabolism; D000076182:Sp7 Transcription Factor; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D000099174:Pigment Epithelium-Derived Factor
D055395:Bone Morphogenetic Protein 1; D024042:Collagen Type I; D021983:Cyclophilins; D016326:Extracellular Matrix Proteins; D005136:Eye Proteins; D018832:Molecular Chaperones; D009414:Nerve Growth Factors; D011393:Procollagen-Proline Dioxygenase; D011506:Proteins; D015843:Serpins; D000076182:Sp7 Transcription Factor; D014157:Transcription Factors; D000099174:Pigment Epithelium-Derived Factor; C108053:CRTAP protein, human; C478163:SP7 protein, human; C081786:cyclophilin B; C525705:BMP1 protein, human