Bone Abstracts

Osteogenesis imperfecta (OI) is a genetic bone dysplasia characterized by recurrent fractures and reduced bone mineral density. The severity of its symptoms varied from very mild to severe, which strongly affect the quality of life and cause premature death.

The aim of the study is to compare the clinical symptoms of different types of osteogenesis imperfecta and to present diagnostic difficulties based on the analysis of our patients.

Patients and methods: The study included 83 patients with a diagnosis of osteogenesis imperfecta (type I, 34 children; type III, 30; and type IV, 19), at the age from 1 week to 18 years. A survey on the appearing ailments and the previously used therapy, paediatric and anthropometric examination were conducted. Bone densitometry using dual energy X-ray absorptiometry was performed. In 20 patients COL1A1 gene by direct sequencing was analyzed.

Results: We revealed a statistically significantly lower bone mineral density in patients with type III OI, the best bone mineral density was in patients with OI type I (P<0.05). The total number of fractures ranged from 0 to 40, but there was no significant difference in the average fracture number between different types of OI. Skeletal deformities were present in 50/83 subjects and were the most common in patients with type III (27/30). The blue sclerae was present in the 68/83 subjects, mostly in types I and III. Dentinogenesis imperfecta was diagnosed only in 18/83 patients, with a similar frequency in all types of OI. There were no significant differences in the number of fractures and bone mineral density, or in other phenotypic manifestations of OI between patients with and without identified mutation in COL1A1.

Conclusions: • OI is a heterogeneous group of skeletal disorders associated with increased fracture risk, characterized by different genetic background and variable clinical course.

• Symptoms subject to variable phenotypic expression in different patients with the same type of OI, which often make it difficult to determine the correct diagnosis and prognosis.

Acknowledgements: The study was financed as a grant NN407 060 938.