Binh Ho Duy will defend his doctoral thesis titled „Osteogenesis imperfecta in Vietnam“ on 15 June 2017 at 14:00.
Associate Professor/Senior Research Fellow Katre Maasalu, University of Tartu
Associate Professor/Senior Research Fellow Aare Märtson, University of Tartu
Professor/Lead Research Fellow Sulev Kõks (PhD), University of Tartu
Professor Li Felländer-Tsai (MD, PhD), Department of Clinical Science, Intervention and Technology, Karolinska Institute, Stockholm, Sweden
Osteogenesis Imperfecta (OI), known also as “brittle bone disease”, is a rare genetic disorder of bones. OI is characterized by low bone mass, bone fragility, and skeletal deformity. The variability of the OI ranges from mild to lethal forms. In addition to bone fragility and skeletal deformities, patients may develop a short stature, dentinogenesis imperfecta, blue eye sclerae and progressive hearing loss. At present, about 90% of OI cases arise due to mutations in the collagen genes. Some OI cases remain genetically undiagnosed and pathogenesis and genetics are not completely known. There is still no evidence of an association between OI with gender, race, or ethnic group.
OI was not been studied in a Vietnamese population before. The aims of this study were to describe the epidemiology, clinical features, and mutations in the collagen genes among Vietnamese OI patients.
A totally 146 OI patients from 120 OI families were included in the study. There was 99 families without previous OI history and 21 families had two or more generations of OI history. All patients had skeletal deformations. 34 OI patients had a history of intrauterine fractures. There were 18 patients (12.33%) who had suffered over 30 fractures. The mean number of lifetime fractures for was 13.23. There was 117 OI patients with blue sclera, 89 dentinogenesis imperfecta and 26 hearing loss.
DI was indentifed in 60.96% patients with OI. Genetic analysis suggests presence of correlation between DI and abnormality of collagen type I. The occlusal features were common in OI patients.
We identified COL1A1 mutations in 36.3% and COL1A2 mutations in 23.1% of patients, which is lower compared to other populations. Also, the amount of discovered novel pathogenic variants is different from previous studies.
The number of found affected individuals and severe phenotypes indicates that the disease is underdiagnosed in Vietnam. The results will find practical use in educating of physicians about the signs of OI in order to improve diagnosis and prevention of complications of this rare disorder. Our data also showed a lower number of collagen OI pathogenic variants in studied Vietnamese patients compared to reported rates for other OI populations. Current study showed that Vietnamese OI population is unique for investigation of OI phenotype and genotype.