1、Genotype-phenotype Correlations In Chinese Osteogenesis Imperfecta Patients 2、Two-year Clinical Trial Of Oral Alendronate Versus Intravenous Zoledronic Acid In Children With Osteogenesis Imperfecta 3、Gorham-stout Disease: Radiological, Histologica

Part 1. Genotype-Phenotype correlations in Chinese osteogenesis imperfecta patientsIntroduction Osteogenesis imperfecta (01) is a heterogenous congenital bone disease characterized by decreased bone mass and increased bone fragility. There are 17 candidate genes for OI, with COL1A1 and COL1A2 being the most common ones, which accounts for about 90% of OI. Traditional Sanger sequencing is time-consuming and prohibitively time-consuming for molecular diagnosis of OI.Methods We developed next generation sequencing (NGS) platform that could allow detection of 12 OI candidate genes. Sanger sequencing was then performed to confirm the results of NGS.We also explored possible genotype-phenotype relation among type I collagen encoding gene COL1A1 and COL1A2.Results The overall coverage for NGS platform was 200X. After Sanger sequencing validation, we found that NGS was able to reach a sensitivity of 90.2% and specificity of 100%.12 patients were identified to carry COL1A1 mutations that lead to haploinsufficiency where as 40 patients were caused by substitutions of glycine by other amino acid in the triple-helical domain of type I collagen. Patients with COL1A1 haploinsufficiency(-0.6±1.1) were taller than those with helical mutations(-5.5±4.6, P=0.007). In the group of patients with helical mutations, neither the type of a chain affected, nor the type of amino acid substituting for glycine, nor the position of the mutation in the a chain were found to have relationship with patients phenotype. Conclusion NGS is a fast and accurate method to make molecular diagnosis of OI patients. Individuals with quantitative defect of type I collagen were higher than those with qualitative defect.Part 2.Two-year clinical trial of oral alendronate versus intravenous zoledronic acid in children with osteogenesis imperfectaAbstractIntroduction Children and adolescents of osteogenesis imperfecta (OI) suffered from bone loss and increased fracture risk. Bisphosphonates were proved to increase bone mineral density (BMD) in OI patients, the effects on decrease fracture risk is controversial. We aimed to compare the efficacy and safety of intravenous zoledronic acid for OI patients using a 2-year, prospective, randomized design.Methods The study included 161 patients of OI aged from 2-16 years old. Patients were randomized in 2:1 ratio to receive either weekly oral alendronate 70mg or once-yearly zoledronic acid. The primary outcome was percentage change from baseline in lumbar spine BMD (LS BMD). The secondary outcomes included percentage from baseline in femoral neck BMD (FN BMD), LS BMD Z scores, FN BMD Z scores, bone turnover markers, and fracture incidence. The primary efficacy analysis was done by ANCOVA, with age and baseline as covariate, and treatment as fixed factors, and. Analysis of both efficacy and safety were based on the in intention-to-treat population.Results Of the 136 patients completed the 2-year clinical trial,90 were assigned to alendronate and 46 received zoledronic acid. The mean±SD increases in the LS BMD percentage change were 60.01%±7.08% for alendronate and 62.04%±5.9% for zoledronic acid. Serum ALP decreased by-20.79%±5.19% in alendronate and -25.71±3.91% in zoledronic acid (P=0.859). Serum β-CTX decreased by -26.1%±6.48% in alendronate and -33.79%±4.78%(P=0.644) in zoledronic acid group. Both group significantly decreased clinical fracture incidence, but zoledronic acid was superior to alendronate in decreasing fracture rate (hazard ratio 0.23,95% CI 0.118-0.431). Adverse events were reported more frequently in zoledronic acid then alendronate, but there was no difference in incidence of severe side effects between the two groups.Conclusions One 5-mg infusion of ZOL and weekly ALN increase BMD, decrease fracture incidence and were generally tolerated in OI patients. The intravenous route is more effective and more acceptable than oral route.Part 3. Gorham-Stout disease:radiological, histological, and clinical features of 12 casesAbstractIntroduction Gorham-Stout disease (GSS) is an exceedingly rare disease characterized by progressive osteolysis and angiomatosis. We investigate the features of this disease and evaluate the effects of bisphosphonates (BPs) on it.Methods The clinical, radiological, and pathological characteristics of 12 patients diagnosed with GSS in Peking Union Medical College were summarized. Immunohistochemical staining with specific lymphatic endothelial markers (D2-40), vascular markers (CD 31, CD 34), and vascular endothelial growth factor (VEGF) and vascular endothelial growth factor receptor 3 (VEGFR-3) was performed in specimens of bone biopsy. Patients were treated with either BPs or conjunction therapy of radiation and BPs. The effects of BPs were evaluated by the change of radiological progression, bone mineral density (BMD) and bone turnover biomarkers.Results Idiopathic massive osteolysis was found in all patients, including 11 polyostotic and one mono-ostotic osteolysis. Soft tissue lymphangioma was presented in four patents. Four patients were complicated with chylothorax. Endothelial cells lining the proliferative vessels were positive for CD31 and CD34 and D2-40. Mild expression of VEGF and VEGFR-3 was also revealed. Stabilization in osteolysis and improvement in BMD were observed after single therapy with BPs or combined with radiotherapy. High mortality rate was found in patients with chylothorax. Spontaneous, progressive osteolysis is the most typical sign of GSS. BPs and radiotherapy can contribute to the clinical stabilization in bone lesion of GSS. The complicated chylothorax possibly indicates poor prognosis.Conclusion GSS is an extremely rare, peculiar musculoskeletal disorder in which the affected bone virtually disintegrates and is replaced by lymphatic vessel or vascular connective tissue.Bisphosphonates or radiotherapy might be helpful in arresting bone lesion progression of GSS.