Lumbar Scheuermann's disease found in a patient with osteogenesis imperfecta (OI) caused by a heterozygous mutation in COL1A2 (c.4048G > A): a case report

Background Osteogenesis imperfecta (OI) is a heterogeneous connective tissue disorder characterized by increased bone fragility and a series of extraskeletal manifestations. Approximately 90 % of OI cases are caused by type I collagen variants encoded by the collagen type I alpha 1 (COL1A1) or type I alpha 2 (COL1A2) gene. Lumbar Scheuermann's disease is an atypical type of Scheuermann's disease accompanied by Schmorl's nodes and irregular endplates but without pronounced kyphosis. Although the etiology of Scheuermann's disease is unclear, genetic and environmental factors are likely. Case presentation Here, we report a 32-year-old male patient who experienced multiple brittle fractures. Gene sequencing revealed a heterozygous mutation, c.4048G > A (p.G1350S), in the COL1A2 gene, and the patient was diagnosed with OI. Magnetic resonance imaging of his thoracolumbar spine revealed multiple Schmorl's nodes. Conclusions This is the first reported case of OI coexisting with the spinal presentation of Scheuermann's disease. It is speculated that the COL1A2 gene mutation might be an underlying novel genetic cause of Scheuermann's disease. In conclusion, this case demonstrates the relationship between Scheuermann's disease and OI for the first time and enriches the genotype-phenotype spectrum of OI.