0000000000011627
AUTHOR
Rolf E. Brenner
Osteogenesis imperfecta: a clinical study of the first ten years of life.
One hundred twenty-seven children with osteogenesis imperfecta (O.I.) were studied during the first 10 years of life. According to Sillence, 40 patients were assigned to type I, 39 to type III, and 48 to type IV O.I. Centiles for height, weight, and the annual number of fractures could be established for the different types of O.I. The development of the skeletal changes could be documented for the different forms of the disease. At birth, the skeletal changes were significantly more severe in type III than in type IV patients. During the first 10 years of life the number of fractures, extent of skeletal deformities, and growth retardation did not differ between types III and IV. Only fract…
Ehlers-Danlos syndrome type VII: phenotype and genotype
A patient suffering from a severe form of Ehlers-Danlos syndrome is presented (EDS type VII). The presence of bilateral congenital hip dislocation, generalized joint hypermobility and a soft hyperelastic skin with abnormal scarring suggested a specific collagen type I defect. SDS-PAGE analysis of collagens secreted into the medium of fibroblast cultures showed a retarded migration of more than half of the alpha 2(I) chains. CNBr peptide mapping of the HPLC-purified altered chain localized the mutant locus to the N-terminal region of the protein. cDNA analysis of the corresponding gene COL1A2 revealed, in addition to the expected collagen sequence, a transcript missing the entire exon 6. Thi…
Osteogenesis imperfecta and hyperplastic callus formation: light- and electron-microscopic findings.
In rare cases of osteogenesis imperfecta, an "overshoot" growth of new bone may occur, which, clinically gives the impression of a tumour. This condition is known as hyperplastic callus formation. Morphology showed an excessive mixed desmal-chondral osteoneogenesis. Atypical collagen fibrils in non-callus tissue represent an indicator for this callus formation in individual patients.
Hydroxylation of collagen type I: evidence that both lysyl and prolyl residues are overhydroxylated in osteogenesis imperfecta
The composition of the collagens secreted into the media of fibroblast cultures of 39 patients with osteogenesis imperfecta (OI) was the same in controls and OI cultures. An abnormal migration pattern of collagens upon SDS-PAGE was evident in one third of the cultures investigated. Lysyl and prolyl hydroxylation of HPLC-purified alpha 1(I) chains was elevated in about 60% of cultures. The degree of hydroxylation was highest in the lethal forms. The extent of lysyl and prolyl hydroxylation showed a strong correlation (r = 0.74, P < 0.001). While high levels of hydroxylation are frequently observed in OI patients, a direct correlation between lysyl or prolyl hydroxylation and fracture rate or…