大理石骨病

Genetic bone diseases are a rare group of afflictions suffered by the general population. However, their rarity should not diminish research efforts to help patients understand and treat their diseases. This review summarizes the pathology, symptoms, diagnosis, and treatment insight into six well-known genetic bone diseases. Only six bone diseases are included due to the relatively low prevalence of them as whole limiting our scope to ensure accurate information and attention is provided for each disease individually. A literature search of PubMed is conducted, including studies published within the past five years (January 2020-December 2025). Thirty-six studies met inclusion criteria, and no significant risk of bias is identified among the selected articles. Study findings are synthesized into disease overview, clinical and radiographic features, and diagnostic and treatment approaches. Actively developing or novel therapies relevant to each disease are also included. These treatments include: fresolimumab for osteogenesis imperfecta, small interfering ribonucleic acid (RNA) therapy for Osteopetrosis, denosumab for Paget's disease of bone, vosoritide/recifercept/infigratinib for achondroplasia, mesenchymal stem cell therapy for craniosynostosis, and combination losartan and atenolol therapy for Marfan syndrome. These treatments are generally more recently acknowledged in literature and are either actively undergoing research or require further research to determine their efficacy.

Pediatric osteopetrosis presents a significant technical challenge for fracture fixation due to the bone's dense yet brittle nature and frequently absent medullary canal. Traditional drilling methods risk excessive torque, drill-bit breakage, and iatrogenic fractures. Here, we describe a serial drilling technique for plate-and-screw fixation in a 5-year-old child with osteopetrosis who sustained sequential subtrochanteric femur fractures 8 months apart. By creating a small pilot hole, sequentially enlarging it with intermediate bits under copious irrigation, and inserting locking screws manually, we achieved stable fixation with no observed instrument failure or intraoperative complications. This method may provide a practical technical strategy for surgeons managing similarly dense osteopetrotic bone.

Osteopetrosis is a genetic disorder characterized by impaired osteoclast function, leading to diffuse osteosclerosis, brittle bones, and hematologic abnormalities. Herein, we report the case of a 55-year-old woman diagnosed with adult-onset osteopetrosis at age 33 after imaging demonstrated dense and marbled long bones, sclerotic medullary canals, vertebral endplate thickening, and hepatosplenomegaly. Bone marrow biopsy revealed preserved megakaryocytes, yet she experienced recurrent episodes of thrombocytopenia that responded to oral steroids and ultimately resolved following splenectomy, supporting an immune-mediated etiology of thrombocytopenia clinically managed as immune thrombocytopenic purpura. The clinical course was further complicated by multiple periprosthetic fractures, highlighting both the diagnostic and management challenges of this condition.

Autosomal dominant osteopetrosis (ADO) is a rare bone disorder caused by impaired osteoclastic resorption. Despite high bone mass, ADO is paradoxically associated with increased fracture risk. High-resolution peripheral quantitative computed tomography (HR-pQCT) provides unique, low-radiation assessments of bone, but prior studies in ADO are limited to small case series. Using baseline cross-sectional data from an ongoing natural history study, we characterized HR-pQCT phenotypes in adults with ADO and explored associations with self-reported fracture history and bone turnover markers. HR-pQCT outcomes at the distal ends and shafts of the radius and tibia in 48 adults with ADO were compared to 144 matched controls (1, 3 ratio). In addition, z-scores for outcomes in ADO were calculated using established reference data. At trabecular-rich distal sites, ADO demonstrated markedly elevated total volumetric bone mineral density (vBMD), trabecular vBMD, trabecular bone volume fraction, trabecular thickness, and estimated failure load (all p<0.001), with values often approaching or exceeding twice those in controls. At cortical-rich shaft sites, total vBMD, bone area, bone area fraction, and cortical thickness were greater in ADO (all p<0.05). However, there was considerable interindividual variability, with some individuals having normal z-scores while others exhibited z-scores exceeding +20. The phenotype reflected increased bone mass rather than mineralization-cortical vBMD was normal and tissue mineral density was normal-to-lower in ADO. Outcomes at both distal and shaft sites were strongly correlated with lifetime fracture number (Spearman ρ=0.64-0.75, p<0.001), indicating ADO individuals with the "strongest" bones (via micro-finite element modeling) reported most fractures. The outcomes were correlated inversely with serum C-telopeptide and positively with serum tartrate resistant acid phosphatase 5b, consistent with ADO being rich with dysfunctional osteoclasts. Overall, the data reveal the profound, yet variable, phenotype in ADO and indicate that HR-pQCT measures correlate with disease severity and represent potential surrogate endpoints for future therapeutic trials.

LRRK1 is essential for osteoclast-mediated bone resorption, and loss of LRRK1 function causes osteopetrosis in mice and humans. However, the mechanisms by which LRRK1 regulates osteoclast activity remain incompletely defined. We previously identified that phosphorylation of OSTM1 at threonine 328 and serine 329 was compromised in LRRK1-deficient osteoclasts. To test the role for OSTM1 phosphorylation in LRRK1 regulation of osteoclast functions, we expressed a phosphomimetic OSTM1 variant in LRRK1-null osteoclasts. Overexpression of phosphomimetic, but not a dephosphomimetic variant, partially restored resorptive activity in LRRK1-deficient osteoclasts in vitro. To test OSTM1's role in rescuing defective bone resorption in Lrrk1-null mice, we generated Ostm1-T328E/S329D knock-in (KI) mice and crossed them onto the Lrrk1-deficient background. Ostm1-T328E/S329D KI mice displayed normal skeletal development and bone remodeling. When crossed to the Lrrk1-deficient background, OSTM1-T328E/S329D expression increased osteoclast resorptive activity and bone formation and partially improved trabecular architecture, although bone volume remained unchanged. These findings demonstrate that OSTM1 phosphorylation contributes to LRRK1-dependent regulation of osteoclast function and identify the LRRK1-OSTM1 pathway as a mechanistic node controlling bone resorption. Our work provides new insight into the molecular basis of LRRK1-mediated osteoclast function and highlights OSTM1 phosphorylation as a potential therapeutic target for metabolic bone diseases.