Osteogeneza niedoskonała: objawy kliniczne, czynniki etiologiczne oraz współczesne strategie terapeutyczne

The clinical spectrum of osteogenesis imperfecta is exceptionally broad, ranging from mild forms with minimal skeletal deformation to perinatal lethal variants. The hallmark feature is bone fragility, predisposing individuals to frequent fractures following minimal mechanical impact. Principal clinical manifestations include:

• Skeletal Deformities: Progressive scoliosis, kyphosis, chest wall abnormalities, and bowing of long bones resulting from recurrent micro-fractures and improper healing.
• Blue Sclerae: Caused by translucency of the thinned connective tissue allowing visualization of the underlying choroidal veins.
• Dentinogenesis Imperfecta: Anomalies affecting primary and permanent teeth, rendering them opalescent, brittle, and prone to rapid wear.
• Hearing Impairment: Conductive, sensorineural, or mixed hearing loss often manifesting during early adulthood due to otosclerosis-like changes in the ossicles.

Traditionally categorized using the Sillence classification (Types I–IV) based on clinical severity and inheritance, contemporary diagnostic frameworks incorporate molecular genetics to identify over 20 distinct genetic variants.

The fundamental etiology of osteogenesis imperfecta involves structural or quantitative abnormalities in type I collagen, the principal organic component of bone matrix. Approximately 85% to 90% of cases stem from heterozygous mutations in the COL1A1 (17q21.33) or COL1A2 (7q21.3) genes encoding the pro-alpha 1 and pro-alpha 2 chains of type I collagen.

Mutations either decrease the total amount of normally structured collagen (quantitative deficiency, characteristic of mild forms) or substitute critical amino acids (such as glycine) within the triple helix domain. This structural disruption exerts a dominant-negative effect, impairing higher-order collagen fibril assembly and resulting in severe skeletal pathology. Autosomal recessive forms involve non-collagenous modifying proteins, including enzymes responsible for prolyl 3-hydroxylation and folding.

Comprehensive care for individuals with osteogenesis imperfecta demands a coordinated, multidisciplinary team comprising pediatricians, geneticists, orthopedic surgeons, endocrinologists, and physical therapists. The primary objectives are maximizing bone strength, minimizing fracture frequency, alleviating pain, and fostering functional independence.

Key pillars of modern management include:

• Pharmacological Treatment: Bisphosphonates (such as pamidronate and zoledronic acid) represent the cornerstone of therapy. By suppressing osteoclast-mediated bone resorption, they significantly increase bone mineral density and reduce bone pain and fractures.
• Orthopedic and Surgical Care: Intramedullary rodding procedures (including telescopic nails) correct long-bone deformities and reinforce structural integrity, enabling safe weight-bearing and ambulation.
• Physical Therapy: Tailored rehabilitation programs focusing on core stability, safe motor skill development, and aquatic therapy, while strictly avoiding high-impact forces or torsional stress.

Emerging therapies, including anti-RANKL antibodies, sclerostin inhibition, and regenerative medicine approaches, continue to undergo clinical evaluation to further refine treatment outcomes.