Vitamin D affects several body functions, and thus general health, due to its pleiotropic activity. It plays a key role in bone metabolism, and its deficiency impacts bone development, leading to bone fragility. In osteogenesis imperfecta (OI), a group of hereditary connective tissue disorders characterized by bone fragility, additional factors, such as vitamin D deficiency, can affect the expression of the phenotype and aggravate the disorder. The aim of this scoping review was to assess the incidence of vitamin D deficit in OI patients and the association between vitamin D status and supplementation in individuals affected by OI. We searched the PubMed Central and Embase databases and included studies published between January/2000 and October/2022 evaluating vitamin D measurement and status (normal, insufficiency, deficiency) and supplementation for OI. A total of 263 articles were identified, of which 45 were screened by title and abstract, and 10 were included after a full-text review. The review showed that low levels of vitamin D was a frequent finding in OI patients. Vitamin D supplementation was mainly indicated along with drug therapy and calcium intake. Even if widely used in clinical practice, vitamin D supplementation for OI individuals still needs a better characterization and harmonized frame for its use in the clinical setting, as well as further studies focusing on its effect on bone fragility.

Pycnodysostosis is an ultra-rare osteosclerotic skeletal disorder characterized by short stature, susceptibly to fractures, acroosteolysis of the distal phalanges, and craniofacial features (frontal bossing, prominent nose, obtuse mandibular angle, micrognathia). Dental abnormalities (delayed eruption of teeth, hypodontia, malocclusion, dental crowding, persistence of deciduous teeth, enamel hypoplasia, and increased caries) are also frequent; due to bone metabolism alteration, the patients have an increased risk for jaw osteomyelitis, especially after tooth extraction or mandible fracture. Other complications are obstructive sleep apnea, endocrine alterations and cytopenia. Pycnodysostosis is caused by biallelic loss of function variants in CTSK gene, coding the lysosomal protease cathepsin K. CTSK is involved in the degradation of bone matrix proteins, such as type I and type II collagen. In pycnodysostosis, this degradation is decreased, leading to increased bone density and bone fragility with pathological fractures and poor healing. We present a clinical report of a female adult patient with typical pycnodysostosis phenotype. At the age of 52 years, she had a pathological spontaneous fracture of the right mandible complicated by osteonecrosis, treated with load bearing osteosynthesis. The direct sequencing of CTSK gene revealed the presence of the pathogenic homozygous variant c.746T>A, (p.Ile249Asn), that confirmed the diagnosis of pycnodysostosis. We also review the literature case series published to date, that suggest to always consider the diagnosis of pycnodysostosis in case of osteosclerosis, even in the absence of brachydactyly or short stature. This report details the natural history of the disease in this patient, from childhood to adulthood, and highlights the importance of a quality of life assessment. In addition, we describe a case of mandibular osteonecrosis and spontaneous fracture in pycnodysostosis, drawing attention on the maxillofacial complications in these patients and on the importance of a personalized follow-up.

Background: Multiple epiphyseal dysplasia (MED) is a clinically and genetically heterogeneous group of skeletal diseases characterized by epiphyseal abnormalities associated with mild short stature. The clinical variability is wide, and the first clinical manifestations still occur in childhood with joint pain and stiffness that evolve into degenerative joint disease. MED, caused by mutations in the Cartilage Oligomeric Matrix Protein (COMP) gene, is the most common form of the disease. COMP-MED usually shows significant involvement of the capital femoral epiphyses and irregular acetabulum; instead, COL9A1-, COL9A2-, and COL9A3-MED appear to have more severe knee involvement than hips, resulting in a milder presentation than COMP-MED cases. Other complications have been reported, in particular osteochondritis dissecans (OCD), which has been described in two large COL9A2-related MED families associated with myopathy. Methods: Here, we report the case of a 24-year-old man affected by COMP-MED with a positive family history for the disease and a clinical presentation that interestingly is characterized by the presence of multiple OCD. Results: To our knowledge, this is the first case of COMP mutations related to multiple OCD as the main clinical feature. Conclusions: This report can expand the clinical phenotype related to the pathogenic variants of the COMP gene, as it shows that multiple OCD can also be present in COMP-related MED as well as in COL9A2-related MED.

Background: This study aimed to describe pain characteristics in patients diagnosed with Ehlers–Danlos syndrome (EDS) or hypermobility spectrum disorders (HSD) and to identify factors associated with moderate to severe pain at diagnosis. Methods: Ninety‐six patients were retrospectively identified through the Ce.Ma.R.S. registry (2017–2022). Pain intensity was assessed at first evaluation using a Numeric Rating Scale (0–10). Patients were grouped into no/mild pain and moderate/severe pain. Clinical and demographic data were collected, and variables significant in univariate analysis were included in multivariate logistic regression. Results: At diagnosis, 49% of patients reported moderate to severe pain. Independent predictors were older age (OR = 1.06; 95% CI: 1.03–1.10), diagnosis of hypermobile EDS (OR = 6.25; 95% CI: 1.31–29.74), and headache (OR = 3.97; 95% CI: 1.14–13.82). Use of pain medications, particularly paracetamol and NSAIDs, was strongly associated with higher pain severity ( p < 0.001). Conclusion: Pain is a common and early symptom in EDS and HSD. Older patients, those with hypermobile EDS, and those with headache are at greater risk of severe pain. Early, multidisciplinary pain management, including pharmacological treatment, physiotherapy, and headache‐specific strategies, should be prioritized to improve outcomes and reduce long‐term disability. Trial Registration: ClinicalTrials.gov identifier: NCT04133272

Primary osteoporosis in children and young adults often suggests a monogenic disease affecting bone microarchitecture and bone mineral density. While Osteogenesis Imperfecta (OI) is the most recognized genetic cause of recurrent fractures, many other genes involved in bone metabolism may contribute to osteoporosis. Among them, FGFR2 plays a critical role in bone growth and development by regulating osteoblast differentiation and proliferation, as well as chondrogenesis. Germline pathogenic FGFR2 variants are typically associated with syndromic craniosynostosis, conditions not characterized by bone fragility or osteoporosis. A report recently identified FGFR2 as a potential cause of dominant early-onset osteoporosis and bone fractures in a family. We report the case of a child affected by severe osteoporosis with multiple fractures. We performed clinical exome sequencing in trio to investigate potential genetic causes of the observed phenotype and identified a likely mosaic pathogenic FGFR2 variant, absent in both parental samples. Our findings provide further evidence that FGFR2 pathogenic variants can lead to a novel non-syndromic bone mineralization disorder, reinforcing the role of FGFR2 in the pathogenesis of early-onset osteoporosis.

Background : primary osteoporosis in children and young adults often suggests a monogenic disease affecting bone microarchitecture and bone mineral density. While Osteogenesis Imperfecta (OI) is the most recognized genetic cause of recurrent fractures, many other genes involved in bone metabolism may contribute to osteoporosis. Among them, FGFR2 plays a critical role in bone growth and development by regulating osteoblasts differentiation and proliferation, as well as chondrogenesis. Germline pathogenic FGFR2 variants are typically associated with syndromic craniosynostosis, conditions not characterized by bone fragility or osteoporosis. A report by Dantsev et al. (2023), recently identified FGFR2 as a potential cause of dominant early-onset osteoporosis and bone fractures in a family. Methods: We performed clinical exome sequencing in trio to investigate potential genetic causes of the observed phenotype. Results: We report the case of a child presenting with severe osteoporosis with multiple fractures, carrying a mosaic likely pathogenic FGFR2 variant, absent in both parental samples. Conclusions: Our findings provide further evidence that FGFR2 pathogenic variants can lead to a novel non-syndromic bone mineralization disorder, reinforcing the role of FGFR2 in the pathogenesis of early onset osteoporosis.