Unclassified demineralising bone disease in an 8 years old girl (report of a case)

A Dyadic Nosology for Osteogenesis Imperfecta and Bone Fragility Syndromes 2024

In 2023 following extensive consultation with key stakeholders, the expert Nosology Working Group of the International Skeletal Dysplasia Society (ISDS) published the new Dyadic Nosology for Genetic Disorders of the Skeleton. Some 770 entities were delineated associated with 552 genes. From these entities, over 40 genes resulting in distinct forms of Osteogenesis Imperfecta (OI) and Bone Fragility and/or Familial Osteoporosis were identified. To assist clinicians and lay stake holders and bring the considerable body of knowledge of the matrix biology and genomics to people with OI as well as to clinicians and scientists, a dyadic nosology has been recommended. This combines a genomic co-descriptor with a phenotypic naming based on the widely used Sillence nosology for the OI syndromes and the many other syndromes characterized in part by bone fragility.This review recapitulates and explains the evolution from the simple Congenita and Tarda subclassification of OI in the 1970 nosology, which was replaced by the Sillence types I-IV nosology which was again replaced in 2009 with 5 clinical groups, type 1 to 5. Qualitative and quantitative defects in type I collagen polypeptides were postulated to account for the genetic heterogeneity in OI for nearly 30 years, when OI type 5, a non-collagen disorder was recognized. Advances in matrix biology and genomics since that time have confirmed a surprising complexity both in transcriptional as well as post-translational mechanisms of collagens as well as in the many mechanisms of calcified tissue homeostasis and integrity.

Coalescing expansile skeletal disease: Delineation of an extraordinary osteopathy involving the IFITM5 mutation of osteogenesis imperfecta type V

In 2003, we briefly reported the remarkable osteopathy of a 12-year-old boy who at age two months began fracturing his limbs with subsequent hyperplastic callus formation and expansion and fusion of appendicular bones. By age ten years he had coalesced his lumbosacral spine, pelvis, femurs, and leg and foot bones as a single structure. Computed tomography of expanded bone revealed a thin cortical shell, diminished irregular trabeculae, and cystic areas. Histopathology featured foci of woven bone, densely packed osteocytes, cartilage, fibrovascular tissue, and massive fat deposition in the marrow space lacking hematogenous precursor cells. Bone turnover markers indicated accelerated remodeling and the few radiographically assessable appendicular bones improved during brief adherence to alendronate therapy. Following puberty, serum multiplex biomarker profiling confirmed accelerated bone turnover. At age 23 years, macrospecimens from leg amputation revealed ossification along capsular tissue together with hyaline cartilage degeneration. Concurrently, the life-long course of this same disorder was delineated in an unrelated woman until her death at age 51 years. Both patients demonstrated the radiographic hallmarks and harbored the heterozygous point mutation (c.-14C>T) in the 5'-UTR of IFITM5 associated with osteogenesis imperfecta type V (OI-V). Herein, we detail the clinical, radiological, histopathological, biochemical, and molecular findings and discuss the etiology and pathogenesis of this extraordinary osteopathy that we call coalescing expansile skeletal disease.

Cyclic bisphosphonate therapy in osteogenesis imperfecta type V

The clinical and radiographic features and management of a young person with recently delineated Osteogenesis Imperfecta Type V is described. A female aged 9 years presented with a history of multiple fractures since 3 years of age and bilateral dislocation of the elbows from infancy. She was commenced on a low dose frequent regimen of cyclic intravenous pamidronate, which resulted in progressive improvement in bone density, reduced fracture frequency and remission of symptoms of osteoporosis.