==================================BSR19================================== 19. Identification of the collagen defect in Osteogenesis Imperfecta (OI). OI - Brittle Bone disease. Collagen defect, genetic defect, genetic abnormality, abnormal collagen, Type I collagen: alpha 1 Type I, alpha 2 Type I, Collagen gene. 1 UI - 87108432 AU - Piccirillo A ; Delfino M ; Descalzi Cancedda F ; Cancedda R TI - Altered processing of alpha (I) collagen in a case of lethal osteogenesis imperfecta. AB - Cultured skin fibroblasts from a newborn with the lethal perinatal form of Osteogenesis imperfecta synthesized an over-hydroxylated form of pro alpha 1 (I) chain. The analysis of the CNBr peptides showed that over-hydroxylation occurred all along the molecule. MH - Cells, Cultured ; Collagen/ANALYSIS/*BIOSYNTHESIS ; Electrophoresis, Polyacrylamide Gel ; Fibroblasts/METABOLISM ; Human ; Hydroxylation ; Osteogenesis Imperfecta/FAMILIAL & GENETIC/*METABOLISM ; Peptide Fragments/ANALYSIS ; Proline/METABOLISM ; Support, Non-U.S. Gov't ; Tritium SO - Ital J Biochem 1986 Sep-Oct;35(5):321-7 2 UI - 87060827 AU - Wallis G ; Beighton P ; Boyd C ; Mathew CG TI - Mutations linked to the pro alpha 2(I) collagen gene are responsible for several cases of osteogenesis imperfecta type I. AB - We have analysed six South African families with osteogenesis imperfecta type I using three DNA polymorphisms associated with the pro alpha 2(I) collagen gene. In four of these families linkage of the pro alpha 2(I) gene and the osteogenesis imperfecta phenotype was suggested, whereas in the remaining two families there was a lack of linkage. No distinct correlation could be made between the phenotypic features of the families studied and linkage or lack of linkage to the pro alpha 2(I) gene. Two different haplotypes were found to be associated with the mutant pro alpha 2(I) alleles. These findings suggest that molecular heterogeneity exists within osteogenesis imperfecta type I and that in a significant proportion of cases the defect is linked to the pro alpha 2(I) gene. MH - Case Report ; DNA Restriction Enzymes ; DNA/GENETICS ; Female ; Gene Frequency ; *Genes, Structural ; Heterozygote Detection ; Human ; Male ; *Mutation ; Nucleic Acid Hybridization ; Osteogenesis Imperfecta/ *FAMILIAL & GENETIC ; Pedigree ; *Polymorphism (Genetics) ; Procollagen/ *GENETICS ; Support, Non-U.S. Gov't SO - J Med Genet 1986 Oct;23(5):411-6 3 UI - 87058097 AU - Wenstrup RJ ; Tsipouras P ; Byers PH TI - Osteogenesis imperfecta type IV. Biochemical confirmation of genetic linkage to the pro alpha 2(I) gene of type I collagen. AB - Fibroblasts from two affected members of a large pedigree in which osteogenesis imperfecta (OI) type IV is genetically linked to the pro alpha 2(I) gene of type I collagen synthesize two populations of pro alpha 2(I) chains. One population is normal; the second population appears to have a deletion of about 10 amino acid residues from the middle of the triple helical domain. The mutation in pro alpha 2(I) causes increased posttranslational modification in the amino-terminal half of some pro alpha 1(I) chains, lowers the melting temperature of type I collagen molecules that incorporate a mutant pro alpha 2(I) chain, and prevents or delays the secretion of those molecules from fibroblasts in cell culture. On the basis of this study and linkage studies in additional families, it appears that the OI type IV phenotype is often the result of heterozygosity for mutations in pro alpha 2(I) that alter the triple helical structure of type I collagen. MH - Adolescence ; Adult ; Aged ; Child ; Child, Preschool ; Chromosome Deletion ; Female ; Fibroblasts/METABOLISM ; Human ; *Linkage (Genetics) ; Male ; Middle Age ; Mutation ; Osteogenesis Imperfecta/*FAMILIAL & GENETIC/METABOLISM ; Procollagen/ANALYSIS/BIOSYNTHESIS/*GENETICS ; Protein Conformation ; Support, Non-U.S. Gov't ; Support, U.S. Gov't, P.H.S. SO - J Clin Invest 1986 Dec;78(6):1449-55 4 UI - 87026777 AU - Bonaventure J ; Cohen-Solal L ; Lasselin C ; Allain JC ; Maroteaux P TI - Abnormal procollagen synthesis in fibroblasts from three patients of the same family with a severe form of osteogenesis imperfecta (type III). AB - Dermal fibroblast cultures from three siblings with a severe form of osteogenesis imperfecta were established in order to analyze their procollagen and collagen synthesis. Cell strains from clinically normal consanguineous parents (first cousins), were also obtained for comparison. Total collagen production in culture media was diminished by 55% in the patients fibroblasts and to a lesser extent in the parents. This decrease was specific for collagenous proteins. From polyacrylamide gel electrophoresis, it appeared that the three children had not only the same defective secretion of pro alpha 1(I) molecules but that their pro alpha 1(I) migrated slightly faster than the parental and control counterparts. Analysis of secretion confirmed a reduced rate in procollagen synthesis and the absence of intracellular storage. Upon pepsin treatment, extracellular alpha 1(I) and alpha 2(I) chains were found in the expected ratio of 2:1 and migrated normally, suggesting that the altered mobility of pro alpha 1(I) chains was related to COOH or NH2 terminal propeptides. In agreement with the reduced type I collagen production, an increase in the alpha 1(III)/alpha 1(I) ratio was also detected. Furthermore, after a 2.5-h labelling followed by alkylation with iodoacetamide, free intracellular pro alpha 2(I) and alpha 1(I) chains were detected in the absence of reduction, consistent with an abnormal intracellular ratio of pro alpha 1(I)/pro alpha 2(I) that was measured after dithiothreitol reduction. Analysis of intracellular collagen chains from parental strains following a 4-h incubation demonstrated that pro alpha 1(I) appeared as a doublet, one band with normal mobility and a less intense band migrating faster and corresponding to the defective chain found in the patients. Absence of the abnormal molecules in culture media was related to the demonstration of a defective collagen secretion by parental fibroblasts. Correlation between these biochemical findings and clinical data strongly support a recessive inheritance of the disease that could be classified as a type III form of osteogenesis imperfecta. Patients would be homozygous for the same defective allele and the asymptomatic parents would most likely be heterozygous carriers of the mutation. Although the exact location of the alteration is not yet elucidated, a splicing mutation is suggested. MH - Adolescence ; Adult ; Child ; Child, Preschool ; Collagen/ANALYSIS/ BIOSYNTHESIS ; Electrophoresis, Polyacrylamide Gel ; Female ; Fibroblasts/ METABOLISM ; Human ; Hydroxyproline/METABOLISM ; Infant ; Kinetics ; Male ; Osteogenesis Imperfecta/FAMILIAL & GENETIC/*METABOLISM ; Procollagen/ ANALYSIS/*BIOSYNTHESIS/SECRETION ; Skin/METABOLISM ; Support, Non-U.S. Gov't SO - Biochim Biophys Acta 1986 Oct 31;889(1):23-34 5 UI - 87024752 AU - Bradshaw JP ; Miller A TI - Osteogenesis imperfecta: an x ray fibre diffraction study. AB - The use of x ray fibre diffraction to study the molecular architecture of healthy and diseased human tendon is described. The three dimensional structure of human (finger) tendon is derived to high resolution and is shown to be very similar to that reported for rat tail tendon. In particular the presence of the 38 A row line in the diffraction pattern suggests that a high degree of lateral order within the collagen fibrils is a more widespread feature of tendon tissue than was formerly realised. Axially projected electron density maps of the 670 A unit repeat of the collagen fibrils of this tissue, and of tendon tissue from three cases of osteogenesis imperfecta (OI), are calculated and compared. The results are in agreement with recent biochemical studies in suggesting that type I (Sillence) OI is principally a quantitative, rather than a qualitative, defect of type I collagen biosynthesis. The features by which a molecular lesion may be recognised and characterised from diffraction data are discussed. MH - Animal ; Chemistry ; Collagen ; Fingers/*PATHOLOGY ; Human ; Osteogenesis Imperfecta/ETIOLOGY/*PATHOLOGY ; Rats ; Support, Non-U.S. Gov't ; Tendons/ *PATHOLOGY ; *X-Ray Diffraction SO - Ann Rheum Dis 1986 Sep;45(9):750-6 6 UI - 87006724 AU - Wenstrup RJ ; Hunter AG ; Byers PH TI - Osteogenesis imperfecta type IV: evidence of abnormal triple helical structure of type I collagen. AB - Skin fibroblasts from a patient with mild osteogenesis imperfecta (OI) type IV synthesize two populations of type I procollagen molecules. One population contains pro alpha 1(I) and pro alpha 2(I) chains that migrate normally in sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and a second population contains only slower migrating pro alpha 1(I) and pro alpha 2(I) chains. The total amount of type I procollagen made by OI cells and the ratio of pro alpha 1(I):pro alpha 2(I) is normal. When labeled under conditions that inhibit post-translational modification of pro alpha chains, the OI cells produce only single populations of pro alpha 1(I) and pro alpha 2(I) chains indicating that the apparent increased molecular weight of some OI pro alpha chains is due to excessive post-translational modification rather than peptidyl insertions. Peptide maps indicate that excessive post-translational modification occurs along the entire triple helical segment of some alpha 1(I) and alpha 2(I) chains produced by OI cells. The effect of the mutation is to lower the melting temperature of the molecules containing slow migrating alpha 1(I) and alpha 2(I) chains to 39.5 degrees C (compared to 41.5 degrees C for control), and to delay secretion of the over-modified type I procollagen from OI cells. These data are consistent with a mutation near the carboxyl-terminal end of the triple helical domain which delays triple helical formation and renders all chains available for further post-translational modification amino-terminal to the mutation. Such alterations in triple helical structure, thermal stability, and secretion previously associated only with the lethal OI type II phenotype are thus also seen in the mild OI type IV phenotype. MH - Case Report ; Cells, Cultured ; Collagen/*BIOSYNTHESIS/GENETICS ; Electrophoresis, Polyacrylamide Gel ; Human ; Infant, Newborn ; Male ; Osteogenesis Imperfecta/FAMILIAL & GENETIC/*METABOLISM ; Peptide Mapping ; Procollagen/BIOSYNTHESIS/GENETICS ; Protein Conformation ; Support, Non-U.S. Gov't ; Support, U.S. Gov't, P.H.S. SO - Hum Genet 1986 Sep;74(1):47-53 7 UI - 87001839 AU - Shea-Landry GL ; Cole DE TI - Psychosocial aspects of osteogenesis imperfecta. AB - Osteogenesis imperfecta is a heterogeneous group of inherited disorders characterized by bone fragility and recurrent fractures. It is currently classified into four types on clinical grounds and appears to arise from different disorders of bone collagen synthesis. The biochemical identification of disturbances in collagen metabolism and the genetic delineation of new mutations of collagen genes have made prenatal diagnosis by molecular methods feasible in some cases. Most people with osteogenesis imperfecta suffer frequent fractures (and sometimes consequent serious disability), for which there are few effective preventive measures. This disorder may have a profound psychosocial influence on patients and their families. In this report the extent of this influence is reviewed and aspects important to the medical community are highlighted; these include the emotional burdens imposed by unfounded suspicions of child abuse, the social and financial costs of repeated hospitalization and immobility, and the frustrations generated by the lack of helpful, practical information for families and health care workers. An important social outcome has been the rise of self-help organizations, exemplified by the Canadian Osteogenesis Imperfecta Society. For Canadian families the society has been an important vehicle for exchange of information and an active, positive response to a lifelong, often severely disabling disorder. MH - Canada ; Collagen/BIOSYNTHESIS ; Family ; Human ; Immobilization ; Osteogenesis Imperfecta/CLASSIFICATION/FAMILIAL & GENETIC/METABOLISM/ *PSYCHOLOGY ; Parents ; Physician's Role ; Social Environment ; Societies, Medical ; Support, Non-U.S. Gov't SO - Can Med Assoc J 1986 Nov 1;135(9):977-81 8 UI - 86296519 AU - Delvoye P ; Mauch C ; Krieg T ; Lapiere CM TI - Contraction of collagen lattices by fibroblasts from patients and animals with heritable disorders of connective tissue. AB - Fibroblasts derived from patients and animals presenting various heritable connective tissue disorders were investigated for the ability to retract a reconstituted collagen matrix. When seeded into gels, dermatosparactic calf and sheep fibroblasts did not exhibit the elongated shape of normal fibroblasts and did not contract the collagen lattice to the same extent as control fibroblasts. In contrast, several cell strains obtained from patients with Ehlers-Danlos syndrome type VII displayed contractile properties for collagen gels similar to controls. Delayed contraction was noted by two strains of fibroblasts from patients with Ehlers-Danlos syndrome type IV, whereas fibroblasts from patients with osteogenesis imperfecta, Marfan syndrome and cutis laxa had normal retraction properties. MH - Adult ; Aged ; Animal ; Cattle ; Cells, Cultured ; Child ; Collagen/ *PHYSIOLOGY ; Collagen Diseases/*PHYSIOPATHOLOGY ; Cutis Laxa/ PHYSIOPATHOLOGY ; Ehlers-Danlos Syndrome/PHYSIOPATHOLOGY ; Extracellular Matrix/*PHYSIOLOGY ; Fibroblasts/*PHYSIOLOGY ; Human ; Marfan Syndrome/ PHYSIOPATHOLOGY ; Osteogenesis Imperfecta/PHYSIOPATHOLOGY ; Sheep ; Support, Non-U.S. Gov't SO - Br J Dermatol 1986 Aug;115(2):139-46 9 UI - 86287390 AU - Cohn DH ; Byers PH ; Steinmann B ; Gelinas RE TI - Lethal osteogenesis imperfecta resulting from a single nucleotide change in one human pro alpha 1(I) collagen allele. AB - We have characterized a mutation in a pro alpha 1(I) procollagen gene (COL1A1) that results in lethal (type II) osteogenesis imperfecta. The mutation is a single base change that results in a cysteine-for-glycine substitution at position 988 of the triple-helical portion of half of the alpha 1(I) chains of type I collagen. The mutation thus disrupts the (Gly-Xaa-Yaa)n pattern necessary for triple-helix formation, where Xaa and Yaa are other amino acids. These experiments establish the minimal mutation in a type I collagen gene capable of producing lethal disease, and the lethality demonstrates a selective mechanism for the stringent maintenance of the collagen gene structure. MH - *Alleles ; Amino Acid Sequence ; Base Sequence ; Cloning, Molecular ; Comparative Study ; DNA Restriction Enzymes ; *Genes, Lethal ; *Genes, Structural ; Human ; Infant ; Mutation ; Osteogenesis Imperfecta/ *FAMILIAL & GENETIC ; Procollagen/*GENETICS ; Support, Non-U.S. Gov't ; Support, U.S. Gov't, P.H.S. SO - Proc Natl Acad Sci USA 1986 Aug;83(16):6045-7 10 UI - 86277974 AU - Minor RR ; Sippola-Thiele M ; McKeon J ; Berger J ; Prockop DJ TI - Defects in the processing of procollagen to collagen are demonstrable in cultured fibroblasts from patients with the Ehlers-Danlos and osteogenesis imperfecta syndromes. AB - This is a study of the processing of procollagen to collagen in cultures of skin and tendon fibroblasts. Processing was markedly increased by growing cells for 2-4 days postconfluence and then adding ascorbate to the medium for 2 days prior to labeling with [3H] proline. With this system, more than two-thirds of the pro-alpha chains of type I procollagen in the culture medium, and more than 90% of those in the cell layer, were rapidly processed to pC-alpha, pN-alpha, or alpha chains. Purified, exogenous procollagen was also rapidly processed in cell-free culture medium. The results showed for the first time that exogenous procollagen can be processed in conditioned cell-free medium. The system was then used to compare the processing of procollagen in the medium of normal fibroblasts, cells from one bovine and four human variants of osteogenesis imperfecta, and those from eight human variants of the Ehlers-Danlos syndrome. The cells could be divided into three groups, based on their ability to process type I procollagen: normal, consistently slow, and very slow. The cause of the decreased processing was shown to be associated with either a mutation causing a shortening of an alpha chain or decreased activity of procollagen N-proteinase in cell-free culture medium. Decreased processing of procollagen to collagen occurred with cultured fibroblasts from patients with different forms of both osteogenesis imperfecta and Ehlers-Danlos syndrome. Both of these disease syndromes are associated with abnormalities in the structure or metabolism of procollagen in fibrous connective tissues, bones, and teeth. The results show that defects in the structure, synthesis, or processing of procollagen are readily demonstrated with cultured fibroblasts. MH - Adolescence ; Adult ; Animal ; Cattle ; Cell Line ; Child ; Child, Preschool ; Collagen/*METABOLISM ; Ehlers-Danlos Syndrome/*METABOLISM ; Electrophoresis, Polyacrylamide Gel ; Female ; Fibroblasts/*METABOLISM ; Human ; Infant ; Infant, Newborn ; Male ; Middle Age ; Osteogenesis Imperfecta/*METABOLISM ; Pregnancy ; Procollagen/*METABOLISM ; Support, Non-U.S. Gov't ; Support, U.S. Gov't, P.H.S. SO - J Biol Chem 1986 Jul 25;261(21):10006-14 11 UI - 86274840 AU - St:oss H ; Pontz BF ; Pesch HJ ; Ott R TI - Heterogeneity of osteogenesis imperfecta. Biochemical and morphological findings in a case of type III according to Sillence. AB - A male infant with pale-blue sclerae, who died at the age of 6 weeks through the aspiration of food, presented multiple fractures and deformation of the long tubular bones. The clinical and radiological findings and the course indicated osteogenesis imperfecta, type III, according to Sillence's classification. The family history was unremarkable. Light and electron microscopic studies of iliac crest bone obtained postmortem, showed an abrupt interruption of endochondral ossification, with an active periosteal ossification. In the region of the fractures, a mixed desmochondral callus was seen. The endoplasmic reticulum of the osteoblasts was markedly dilated, the mitochondria were swollen. The osteoid was reduced in quantity. A postmortem analysis of the collagen types I, II and III obtained from skin, cartilage and bone yielded chromatographically normal collagen constituents. An analysis of the amino acids of the collagen alpha-chains showed an increased hydroxylysine content. The radiological findings and the clinical course both indicated type III osteogenesis imperfecta: identical biochemical findings have been described only for type II. The morphological and biochemical findings described here may be a manifestation of a variable expressivity of type III osteogenesis imperfecta. On the other hand, heterogeneity of type II osteogenesis imperfecta cannot be ruled out. MH - Amino Acids/ANALYSIS ; Bone and Bones/METABOLISM/PATHOLOGY/ULTRASTRUCTURE ; Cartilage/METABOLISM ; Case Report ; Chromatography, Ion Exchange ; Collagen/ANALYSIS ; Endoplasmic Reticulum/ULTRASTRUCTURE ; Human ; Hydroxylation ; Hydroxylysine/ANALYSIS ; Infant ; Male ; Mitochondrial Swelling ; Osteoblasts/ULTRASTRUCTURE ; Osteogenesis Imperfecta/ *CLASSIFICATION/METABOLISM/PATHOLOGY ; Proline/ANALYSIS ; Skin/METABOLISM ; Support, Non-U.S. Gov't SO - Eur J Pediatr 1986 Apr;145(1-2):34-9 12 UI - 86265783 AU - van der Rest M ; Hayes A ; Marie P ; Desbarats M ; Kaplan P ; Glorieux FH TI - Lethal osteogenesis imperfecta with amniotic band lesions: collagen studies. AB - An infant was born with osteogenesis imperfecta (OI) and died after 7 days. In addition, there were amniotic constriction bands and amputations of several digits of the upper and lower limbs. The radiologic picture was suggestive of type III OI. Histomorphometric analysis of the bone showed a trabecular bone volume of 15.1% compared to 26.9% for age-matched controls. This was due to a decreased apposition of matrix by the osteoblasts. Because abnormal collagen synthesis has been suggested as the underlying defect in most forms of OI, collagen studies were undertaken using intact tissues. Bone and skin collagen solubilities were strikingly reduced. Shortened type I collagen molecules, representing 25% of the total type I collagen, were produced by pepsin digestion of the demineralized bone matrix. The molecular weight of the shortened collagen, was 10 kd lower than normal for both the alpha 1 and alpha 2 chains as determined by gel electrophoresis. The bone acetic acid-soluble collagen showed few shortened alpha-chains. Twenty-five percent of the acid-soluble bone collagen was cleaved into shortened molecules by a pepsin digestion. The shortened alpha 1 chain was purified by high-performance liquid chromatography (HPLC) and digested with CNBr. The analysis of the resulting fragments by HPLC and by gel electrophoresis unequivocally demonstrated that the shortened alpha 1 chain was derived from the alpha 1(I) chains and that the pepsin sensitivity extends from the amino terminal end of the chain to the alpha 1(I) CB5 peptide, approximately 120 residues inside the triple helix. These studies show a distinct structural abnormality of type I collagen in the bone matrix of this patient resulting in an increased sensitivity of the collagen to general enzymatic proteolysis. The importance of correlating clinical and biochemical information in OI is emphasized; classification and genetic counseling based only on clinical observations are inaccurate. MH - Amniotic Band Syndrome/METABOLISM/*PATHOLOGY ; Bone and Bones/*PATHOLOGY ; Bone Matrix/ANALYSIS ; Case Report ; Chromatography, High Pressure Liquid ; Collagen/*ANALYSIS ; Electrophoresis, Polyacrylamide Gel ; Female ; Human ; Infant, Newborn ; Osteogenesis Imperfecta/FAMILIAL & GENETIC/METABOLISM/*PATHOLOGY ; Skin/*PATHOLOGY ; Support, Non-U.S. Gov't SO - Am J Med Genet 1986 Jul;24(3):433-46 13 UI - 86255965 AU - Sykes B ; Ogilvie D ; Wordsworth P ; Anderson ; Jones N TI - Osteogenesis imperfecta is linked to both type I collagen structural genes. AB - The segregation of the two type I collagen structural gene loci COL1A1 and COL1A2 was analysed in eleven osteogenesis imperfecta pedigrees by means of restriction-site variants at, or close to, these loci. In each case, the OI gene was inherited with one or other collagen locus. As well as identifying the common OI loci the result of this analysis sets limits on the frequency of a third locus and lays the foundation for a widely available antenatal diagnostic test. MH - Chromosome Mapping ; Collagen/*GENETICS ; Female ; *Genes, Structural ; Genetic Marker ; Genotype ; Human ; *Linkage (Genetics) ; Male ; Osteogenesis Imperfecta/DIAGNOSIS/*FAMILIAL & GENETIC ; Paternity ; Pedigree ; Phenotype ; Pregnancy ; Prenatal Diagnosis ; Support, Non-U.S. Gov't SO - Lancet 1986 Jul 12;2(8498):69-72 14 UI - 86250836 AU - de Vries WN ; de Wet WJ TI - The molecular defect in an autosomal dominant form of osteogenesis imperfecta. Synthesis of type I procollagen containing cysteine in the triple-helical domain of pro-alpha 1(I) chains. AB - Synthesis of procollagen was examined in skin fibroblasts from a patient with a moderately severe autosomal dominant form of osteogenesis imperfecta. Proteolytic removal of the propeptide regions of newly synthesized procollagen, followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis under nonreducing conditions, revealed the presence of type I collagen in which two alpha 1(I) chains were linked through interchain disulfide bonds. Fragmentation of the disulfide-bonded alpha 1(I) dimers with vertebrate collagenase and cyanogen bromide demonstrated the presence of a cysteine residue in alpha 1(I)CB8, a fragment containing amino acid residues 124-402 of the alpha 1(I) collagen chain. Cysteine residues are not normally found in the triple-helical domain of type I collagen chains. The heterozygous nature of the molecular defect resulted in the formation of three kinds of type I trimers: a normal type with normal pro-alpha(I) chains, a type I trimer with one mutant pro-alpha 1(I) chain and two normal chains, and a type I trimer containing two mutant pro-alpha 1(I) chains and one normal pro-alpha 2(I) chain. The presence of one or two mutant pro-alpha 1(I) chains in trimers of type I procollagen was found to reduce the thermal stability of the protein by 2.5 and 1 degree C, respectively. In addition to post-translational overmodification, procollagen containing one mutant pro-alpha 1(I) chain was also cleared more slowly from cultured fibroblasts. The most likely explanation for these disruptive changes in the physical stability and secretion of the mutant procollagen is that a cysteine residue is substituted for a glycine in half of the pro-alpha 1(I) chains synthesized by the patient's fibroblasts. MH - Chymotrypsin ; Cyanogen Bromide ; *Cysteine ; Disulfides/ANALYSIS ; Fibroblasts/METABOLISM ; Genes, Dominant ; Human ; Kinetics ; Macromolecular Systems ; Osteogenesis Imperfecta/*FAMILIAL & GENETIC/ METABOLISM ; Peptide Fragments/ANALYSIS ; Procollagen/*BIOSYNTHESIS/ GENETICS ; Protein Conformation ; Skin/*METABOLISM ; Support, Non-U.S. Gov't ; Trypsin SO - J Biol Chem 1986 Jul 5;261(19):9056-64 15 UI - 86250824 AU - Steinmann B ; Nicholls A ; Pope FM TI - Clinical variability of osteogenesis imperfecta reflecting molecular heterogeneity: cysteine substitutions in the alpha 1(I) collagen chain producing lethal and mild forms. AB - We have examined the collagenous proteins extracted from skin and produced by skin fibroblast cultures from the members of a family with mild dominant osteogenesis imperfecta (OI type I). The two affected patients, mother and son, produce two populations of alpha 1(I) chains of type I collagen, one chain being normal, the other containing a cysteine within the triple-helical domain. Both forms can be incorporated into triple-helical molecules with an alpha 2(I) chain. When two mutant alpha (I) chains are incorporated into the same molecule, a disulfide bonded dimer is produced. We have characterized these chains by sodium dodecyl sulfate-gel electrophoresis and CNBr-peptide mapping and by measuring a number of biosynthetic and physical variables. The cysteine was localized to the COOH-terminal peptide alpha (I) CB6. Molecules containing the mutant chains are stable, have a normal denaturation temperature, are secreted normally, and have normal levels of post-translational modification of lysyl residues and intracellular degradation. We have compared and contrasted these observations with those made in a patient with lethal osteogenesis imperfecta in which there was a cysteine substitution in alpha 1(I) CB6 (Steinmann, B., Rao, V. H., Vogel, A., Bruckner, P., Gitzelmann, R., and Byers, P. H. (1984) J. Biol. Chem 259, 11129-11138) and have concluded that the mutation in the present family occurs in the X or Y position of a Gly-X-Y repeating unit of collagen and not in the glycine position shown for the previous patient (Cohn, D. H., Byers, P. H., Steinmann, B, and Gelinas, R. E. (1986) Proc. Natl. Acad. Sci. U. S. A., in press. MH - Adolescence ; Case Report ; Collagen/*GENETICS/ISOLATION & PURIFICATION/ METABOLISM ; Cyanogen Bromide ; *Cysteine ; Human ; Male ; Osteogenesis Imperfecta/*FAMILIAL & GENETIC ; Peptide Fragments/ANALYSIS ; Skin/ METABOLISM ; Support, Non-U.S. Gov't ; *Variation (Genetics) SO - J Biol Chem 1986 Jul 5;261(19):8958-64 16 UI - 86164962 AU - Traub W ; Steinmann B TI - Structural study of a mutant type I collagen from a patient with lethal osteogenesis imperfecta containing an intramolecular disulfide bond in the triple-helical domain. AB - We have built molecular models of collagen type I from a patient with lethal osteogenesis imperfecta incorporating one or two mutant alpha 1(I)-chains which contain a cysteine substituting a glycine near the C-terminal end. In either case, the cysteines can only be accommodated with considerable distortion of the native collagen structure, which disrupts inter-chain contacts. The disturbance of the triple helix is limited to a small local region. This suggests that the most important consequence of the mutation is delayed helix formation leading to overmodification and decreased collagen production, rather than the structural abnormality of the folded molecules, which are only marginally unstable. MH - *Collagen/ANALYSIS ; Disulfides/ANALYSIS ; Human ; Models, Molecular ; Mutation ; Osteogenesis Imperfecta/*METABOLISM ; Protein Conformation ; Support, Non-U.S. Gov't ; Support, U.S. Gov't, P.H.S. SO - FEBS Lett 1986 Mar 31;198(2):213-6 17 UI - 86155746 AU - Falk CT ; Schwartz RC ; Ramirez F ; Tsipouras P TI - Use of molecular haplotypes specific for the human pro alpha 2(I) collagen gene in linkage analysis of the mild autosomal dominant forms of osteogenesis imperfecta. AB - Autosomal dominant osteogenesis imperfecta (OI) is a heterogeneous group of disorders. Molecular haplotypes associated with the pro alpha 2(I) gene of human type I procollagen were used for genetic linkage studies in a group of 10 families with OI. The clinical phenotypes of the families studied were those of OI type I and OI type IV. Evidence for linkage was highly suggestive in the four families with OI type IV (Z = 3.91 for theta = 0). In contrast, little or no indication for linkage was found in the six families with OI type I (Z = .055 for theta = .415). Heterogeneity between the two groups of families was highly significant (chi 2 = 11.14, P = .0008), suggesting that at least two separate gene defects may be the cause of the autosomal dominant forms of OI. MH - Alleles ; DNA/GENETICS ; DNA Restriction Enzymes ; Female ; *Genes, Dominant ; Genetic Marker ; Genotype ; Human ; *Linkage (Genetics) ; Lod Score ; Male ; Osteogenesis Imperfecta/*FAMILIAL & GENETIC ; Pedigree ; Polymorphism (Genetics) ; Procollagen/*GENETICS ; Support, Non-U.S. Gov't ; Support, U.S. Gov't, P.H.S. SO - Am J Hum Genet 1986 Mar;38(3):269-79 18 UI - 86140186 AU - de Wett W ; Sippola M ; Tromp G ; Prockop D ; Chu ML ; Ramirez F TI - Use of R-loop mapping for the assessment of human collagen mutations. AB - R-loop mapping of DNA:RNA hybrids formed between mutant pro-alpha 2(I) mRNAs and appropriate human pro-alpha 2(I) genomic clones was employed to define the location of mutations which result in the synthesis of shortened pro-alpha 2(I) chains in skin fibroblasts from two variants of osteogenesis imperfecta. Hybridization of the genomic clone NJ-9 with pro-alpha 2(I) mRNA from a patient with a mild atypical form of the disease resulted in the identification of mutant pro-alpha 2(I) mRNA lacking the sequences which correspond to exon 11 of the pro-alpha 2(I) collagen gene. Exon 11, a 54-base pair exon, encodes amino acids 73 to 90 of the alpha 2(I) chain. Also, electron microscopy of R-loop structures formed between the genomic clone NJ-1 and mRNA from a variant with a perinatal lethal form of osteogenesis imperfecta visualized pro-alpha 2(I) mRNAs which did not hybridize to the sequences of exon 28, a 54-base pair exon coding for amino acids 448 to 465 of the alpha 2(I) chain. Moreover, nuclease S1 mapping of the variant's mutant pro-alpha 2(I) mRNA, employing the human pro-alpha 2(I) cDNA clone Hf-15, confirmed the location of the mismatch to the sequences corresponding to exon 28. Although the data do not determine the exact nature of the mutations, they illustrate the use of R-loop mapping as an alternative approach to S1 mapping analysis for the detection and localization of collagen mRNA deletions. MH - Base Sequence ; Chromosome Deletion ; Collagen/*GENETICS ; Human ; Microscopy, Electron ; *Mutation ; Nucleic Acid Hybridization ; Osteogenesis Imperfecta/FAMILIAL & GENETIC ; Procollagen/GENETICS ; RNA, Messenger/ANALYSIS ; Support, Non-U.S. Gov't ; Support, U.S. Gov't, P.H.S. SO - J Biol Chem 1986 Mar 15;261(8):3857-62