title: Severe osteogenesis imperfecta caused by a small in-frame deletion in CRTAP.
abstract: Mutations of proteins involved in posttranslational modification of collagen type I can cause osteogenesis imperfecta (OI) inherited in a recessive pattern. The cartilage-associated protein (CRTAP) is part of a heterotrimeric complex (together with prolyl-3-hydroxylase-1 [P3H1] and cyclophilin B) that 3-hydroxylates the alpha 1 chain of collagen type I at proline residue 986 and plays a collagen chaperon role. CRTAP mutations usually cause severe OI. We report on a patient with OI and a homozygous in-frame deletion in CRTAP and a severe form of OI. The girl was born with markedly deformed long bones. Despite intravenous bisphosphonate treatment, she developed multiple vertebral compression fractures and severe scoliosis and at 4 years of age was able to sit only with support. Although CRTAP transcript levels were normal in the patient's fibroblasts, protein levels of both CRTAP and P3H1 were severely reduced. The degree of 3-hydroxylation at proline residue 986 was also decreased. This report characterizes a patient with a CRTAP small in-frame deletion. We are unaware of prior reports of this finding. We suggest that this deletion affects crucial amino acids that are important for the interaction and/or stabilization of CRTAP and P3H1.
authors.affiliation: Genetics Unit, Shriners Hospital for Children and McGill University, Montreal, Canada.
authors.forename: I M Ben
authors.initials: IM
authors.lastname: Amor
authors.forename: F
authors.initials: F
authors.lastname: Rauch
authors.forename: K
authors.initials: K
authors.lastname: Gruenwald
authors.forename: M
authors.initials: M
authors.lastname: Weis
authors.forename: D R
authors.initials: DR
authors.lastname: Eyre
authors.forename: P
authors.initials: P
authors.lastname: Roughley
authors.forename: F H
authors.initials: FH
authors.lastname: Glorieux
authors.forename: R
authors.initials: R
authors.lastname: Morello
mesh_terms: D015153:Blotting, Western; D002675:Child, Preschool; D021983:Cyclophilins / Q000378:metabolism; D005091:Exons; D016326:Extracellular Matrix Proteins / Q000235:genetics* / Q000378:metabolism; D005260:Female; D005333:Fetus / Q000002:abnormalities; D005455:Fluorescent Antibody Technique; D050723:Fractures, Bone / Q000175:diagnosis / Q000235:genetics / Q000473:pathology; D006720:Homozygote; D006801:Humans; D006900:Hydroxylation; D007223:Infant; D007231:Infant, Newborn; D008562:Membrane Glycoproteins / Q000378:metabolism; D018832:Molecular Chaperones; D010013:Osteogenesis Imperfecta / Q000175:diagnosis / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D010375:Pedigree; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D061251:Primary Cell Culture; D011392:Proline / Q000378:metabolism; D064828:Prolyl Hydroxylases; D011509:Proteoglycans / Q000378:metabolism; D012600:Scoliosis / Q000151:congenital / Q000175:diagnosis / Q000235:genetics / Q000473:pathology; D017384:Sequence Deletion
chemical_list: C108053:CRTAP protein, human; D016326:Extracellular Matrix Proteins; D008562:Membrane Glycoproteins; D018832:Molecular Chaperones; D011509:Proteoglycans; C081786:cyclophilin B; D011392:Proline; D064828:Prolyl Hydroxylases; C485657:P3H1 protein, human; D021983:Cyclophilins