The IMPACT Survey in Germany: Genetic testing and diagnosis experiences of people with osteogenesis imperfecta

Introduction: Osteogenesis imperfecta (OI) is a rare hereditary connective tissue disorder, and the diagnostic journey of affected individuals remains poorly characterised. This analysis aims to provide insights on patterns of genetic testing, and diagnostic experiences of individuals with OI in Germany. Methods : The IMPACT Survey, designed by the OI Federation Europe, the OI Foundation and an international expert steering committee, aimed to assess the clinical, humanistic and economic impact of OI. The survey was fielded online from July–September 2021 and open to adults (aged≥18 years) and adolescents (aged 12–17 years) with OI, caregivers (CGs) and other close relatives. Results : Among German respondents (n=221), 56 were CGs providing proxy responses for children with OI (n=58; aged 0–17 years) and 134 were adults with OI. Sex distribution amongst children was largely balanced (41.4% female) with a mean age of 7.9 years (standard deviation [SD] 5.1). Most adults (69.4%) were female with a mean age of 42.6 years (SD 15.8). Self-reported OI severity was comparable across age groups (children: mild 31.0%, moderate 48.3% and severe 20.7%; adults: mild 25.4%, moderate 50.7% and severe 20.9%). Type III OI was most commonly reported in children (20.7%) and Type I in adults (29.9%); around a quarter of children and adults did not know their OI type or reported undefined type. Genetic confirmation of OI status was received by 94.8% of children but only 50.7% of adults; not being offered a test was the primary reason given. Mean age at diagnosis was 0.3 years (SD 0.8) for children and 4.1 years (SD 9.4) for adults; diagnosis had not been received by 12.6% of adults until after the age of 11 years. When experiences were queried, 11.3% children and 8.2% adults reported initial misdiagnosis with a different condition. Misdiagnoses were varied, including stunted growth (n=1 child), neurological disease (n=1 child), scoliosis (n=1 adult), and osteoporosis (n=1 adult). Notably, 20.8% and 14.9% of children and adults respectively indicated that their OI had initially been suspected non-accidental injury. Discussion: Overall, findings suggest that while genetic testing for OI in Germany is now widely available, significant diagnostic challenges persist for individuals with OI and their families. Greater disease-specific awareness is essential to support both clinical practice and the patient community throughout the diagnostic process.