Pycnodysostosis is an inherited autosomal recessive disorder characterized by dysplasia of the skeletal system. It occurs in any human races with no disparity in gender or age predilection. The disease is diagnosed at a young age owing to the frequent fragile bone fractures. Craniofacial and dental manifestations may overlap with those of other craniofacial dysostosis; therefore, precise knowledge is essential in differential diagnosis as it may affect the treatment outcome. Here, we report three cases with typical clinical and radiological features, among which one presented with osteomyelitis of the mandible.

BACKGROUND: Bone tissue homeostasis relies on the coordinated activity of the bone-forming osteoblasts and bone-resorbing osteoclasts. Osteomesopyknosis is considered a distinctive rare sclerosing skeletal disorder of unelucidated pathophysiology and presumably autosomal dominant transmission. However, the causal genes are unknown.
METHODS: We present a case report encompassing clinical assessments, imaging studies, and whole-exome sequencing analysis, complemented by functional in vitro experiments.
RESULTS: This new case of osteomesopyknosis was associated with a missense ALOX5 variant predicted to induce protein misfolding and proteasomal degradation. Transfection experiments demonstrated that the variant was associated with reduced protein levels restored by proteasomal inhibition with bortezomib. Likewise, gene expression analysis showed that the mutated gene was associated with a decreased RANKL/OPG ratio, which is a critical driver of osteoclast precursor differentiation.
CONCLUSIONS: Our data indicate impaired bone resorption as the underlying mechanism of this rare osteosclerosis, implicating ALOX5 pathogenic variants as potential etiological factors.

Raine syndrome (RNS) is a rare autosomal recessive osteosclerotic dysplasia. RNS is caused by loss-of-function disease-causative variants of the FAM20C gene that encodes a kinase that phosphorylates most of the secreted proteins found in the body fluids and extracellular matrix. The most common RNS clinical features are generalized osteosclerosis, facial dysmorphism, intracerebral calcifications and respiratory defects. In non-lethal RNS forms, oral traits include a well-studied hypoplastic amelogenesis imperfecta (AI) and a much less characterized gingival phenotype. We used immunomorphological, biochemical, and siRNA approaches to analyze gingival tissues and primary cultures of gingival fibroblasts of two unrelated, previously reported RNS patients. We showed that fibrosis, pathological gingival calcifications and increased expression of various profibrotic and pro-osteogenic proteins such as POSTN, SPARC and VIM were common findings. Proteomic analysis of differentially expressed proteins demonstrated that proteins involved in extracellular matrix (ECM) regulation and related to the TGFβ/SMAD signaling pathway were increased. Functional analyses confirmed the upregulation of TGFβ/SMAD signaling and subsequently uncovered the involvement of two closely related transcription cofactors important in fibrogenesis, Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ). Knocking down of FAM20C confirmed the TGFβ-YAP/TAZ interplay indicating that a profibrotic loop enabled gingival fibrosis in RNS patients. In summary, our in vivo and in vitro data provide a detailed description of the RNS gingival phenotype. They show that gingival fibrosis and calcifications are associated with, and most likely caused by excessed ECM production and disorganization. They furthermore uncover the contribution of increased TGFβ-YAP/TAZ signaling in the pathogenesis of the gingival fibrosis.

UNASSIGNED: Congenital Generalized Lipodystrophy (CGL) is a rare autosomal recessive disease caused by mutations in genes responsible for the formation and development of adipocytes. Bone abnormalities are described. However, there is a scarcity of data.
UNASSIGNED: To describe bone characteristics in a large CGL1 and 2 case series.
UNASSIGNED: Cross-sectional study that assessed bone radiological features of CGL patients of a reference hospital in Fortaleza (CE), Brazil. Patients underwent clinical and bone mineral metabolism evaluation, radiographs of the axial and appendicular skeleton and bone mineral density (BMD) assessment by DEXA (dual energy X-ray absorptiometry).
UNASSIGNED: Nineteen patients were included, fourteen were CGL1 and 5, CGL2. Median age was 20 years (8-42) and 58% were women. Median BMI and percentage of body fat were, respectively, 21 Kg/m² (16-24), and 10.5% (7.6-15). The median leptin concentration was 1 ng/mL (0.1-3.3). Diabetes mellitus and dyslipidemia were present in 79% and 63% of patients, respectively. Median calcium and phosphate were normal in almost all patients (95%). Median parathyroid hormone and 25-OH-vitamin D were 23 pg/mL (7-75) and 28 ng/mL (18-43). Osteolytic lesions, osteosclerosis and pseudo-osteopoikylosis, were present in 74%, 42% and 32% of patients, respectively. Lytic lesions were found predominantly in the extremities of long bones, bilaterally and symmetrically, spine was spared. Osteosclerosis was present in axial and appendicular skeleton. Pseudo-osteopoikilosis was found symmetrically in epiphyses of femur and humerus, in addition to the pelvis. BMD Z-score greater than +2.5 SD was observed in 13 patients (68.4%). BMD was higher in CGL1 compared to CGL2 in lumbar spine and total body in adults. No associations were found between high BMD and HOMA-IR (p=0.686), DM (p=0.750), osteosclerosis (p=0.127) or pseudo-osteopoikilosis (p=0.342), and, between pain and bone lesions. Fractures were found in 3 patients.
UNASSIGNED: Bone manifestations are prevalent, heterogeneous, and silent in CGL1 and CGL2. Osteolytic lesions are the most common, followed by osteosclerosis and pseudo-osteopoikilosis. Bone mass is high in most cases. There was no pain complaint related to bone lesions. Thus, systematic assessment of bone manifestations in CGL is essential. Studies are needed to better understand its pathogenesis and clinical consequences.

Skeletal fluorosis is rare and occurs secondary to chronic high amounts of fluoride consumption, manifesting as diffuse osteosclerosis, skeletal pain, connective tissue calcification, and increased fracture risk. Methoxyflurane is a volatile, fluorinated hydrocarbon-inhaled analgesic, and the maximum recommended dose is 15 mL (99.9 % w/w) per wk. A rodent study found increased skeletal fluoride after methoxyflurane exposure. However, skeletal fluorosis secondary to methoxyflurane use in humans has rarely been reported. We present the case of a 47-yr-old female with diffuse osteosclerosis secondary to fluorosis from methoxyflurane use for chronic pain, presenting with 3 yr of generalized bony pain and multiple fragility fractures. Lumbar spine BMD was elevated. CT and radiographs demonstrated new-onset marked diffuse osteosclerosis, with calcification of interosseous membranes and ligaments, and a bone scan demonstrated a grossly increased uptake throughout the skeleton. Biochemistry revealed an elevated alkaline phosphatase and bone turnover markers, mild secondary hyperparathyroidism with vitamin D deficiency, and mild renal impairment. Zoledronic acid, prescribed for presumed Paget\'s disease, severely exacerbated bony pain. Urinary fluoride was elevated (7.3 mg/L; reference range < 3.0 mg/L) and the patient revealed using methoxyflurane 9 mL per wk for 8 yr for chronic pain. A decalcified bone biopsy revealed haphazardly arranged cement lines and osteocytes lacunae and canaliculi, which was consistent with an osteosclerotic process. Focal subtle basophilic stippling around osteocyte lacunae was suggestive of fluorosis. Although fluorosis is not a histological diagnosis, the presence of compatible histology features was supportive of the diagnosis in this case with clinical-radiological-pathological correlation. Skeletal fluorosis should be considered as a cause of acquired diffuse osteosclerosis. Methoxyflurane should not be recommended for chronic pain. The risk of repeated low-dose exposure to fluoride from methoxyflurane use as analgesia may be greater than expected, and the maximum recommended dose for methoxyflurane may require re-evaluation to minimize skeletal complications.
UNASSIGNED: Skeletal fluorosis is rare and occurs secondary to chronic high amounts of fluoride consumption, manifesting as diffuse osteosclerosis, skeletal pain, connective tissue calcification, and increased fracture risk. We present the case of a 47-yr-old female with skeletal fluorosis secondary to long-term methoxyflurane for chronic pain. The risk of repeated low-dose exposure to fluoride from methoxyflurane use for analgesia may be greater than expected, and the maximum recommended dose for methoxyflurane may require re-evaluation to minimize skeletal complications.

BACKGROUND: Osteopetrosis is a rare hereditary disease that can be transmitted in an autosomal recessive or autosomal dominant.
METHODS: Here, we report a case of trochanteric fracture in an 18-year-old boy with an anatomical plate. At the last follow-up, 24 months after surgery, the fracture had healed well, and the patient was not restricted in his activities.
CONCLUSIONS: Osteopetrosis is a rare bone disease that is mainly caused by osteoclast dysfunction. It results from a remodelling defect that leads to hypermineralization of the skeleton, resulting in bone fragility. Both surgical and nonsurgical management have advantages and disadvantages. Thus, open reduction and anatomic plate fixation remain effective management modalities for trochanteric fractures in osteopetrosis patients.
CONCLUSIONS: For our patient and as described in the literature, the complication rate decreases as some principles are respected with better consolidation of the osteoporotic fracture.

The host environment is of critical importance for antibiotic efficacy. By impacting bacterial machineries, stresses encountered by pathogens during infection promote the formation of phenotypic variants that are transiently insensitive to the action of antibiotics. It is assumed that these recalcitrant bacteria-termed persisters-contribute to antibiotic treatment failure and relapsing infections. Recently, we demonstrated that host reactive nitrogen species (RNS) transiently protect persisters against the action of β-lactam antibiotics by delaying their regrowth within host cells. Here, we discovered that RNS intoxication of persisters also collaterally sensitizing them to fluoroquinolones during infection, explaining the higher efficiency of fluoroquinolones against intramacrophage Salmonella. By reducing bacterial respiration and the proton-motive force, RNS inactivate the AcrAB efflux machinery of persisters, facilitating the accumulation of fluoroquinolones intracellularly. Our work shows that target inactivity is not the sole reason for Salmonella persisters to withstand antibiotics during infection, with active efflux being a major contributor to survival. Thus, understanding how the host environment impacts persister physiology is critical to optimize antibiotics efficacy during infection.

Idiopathic osteosclerosis (IO) are focal radiopacities of unknown etiology observed in the jaws. These radiopacities are incidentally detected on dental panoramic radiographs taken for other reasons. In this study, we investigated the performance of a deep learning model in detecting IO using a small dataset of dental panoramic radiographs with varying contrasts and features. Two radiologists collected 175 IO-diagnosed dental panoramic radiographs from the dental school database. The dataset size is limited due to the rarity of IO, with its incidence in the Turkish population reported as 2.7% in studies. To overcome this limitation, data augmentation was performed by horizontally flipping the images, resulting in an augmented dataset of 350 panoramic radiographs. The images were annotated by two radiologists and divided into approximately 70% for training (245 radiographs), 15% for validation (53 radiographs), and 15% for testing (52 radiographs). The study employing the YOLOv5 deep learning model evaluated the results using precision, recall, F1-score, mAP (mean Average Precision), and average inference time score metrics. The training and testing processes were conducted on the Google Colab Pro virtual machine. The test process\'s performance criteria were obtained with a precision value of 0.981, a recall value of 0.929, an F1-score value of 0.954, and an average inference time of 25.4 ms. Although radiographs diagnosed with IO have a small dataset and exhibit different contrasts and features, it has been observed that the deep learning model provides high detection speed, accuracy, and localization results. The automatic identification of IO lesions using artificial intelligence algorithms, with high success rates, can contribute to the clinical workflow of dentists by preventing unnecessary biopsy procedure.

UNASSIGNED: Patients with systemic mastocytosis are at high risk of developing osteoporosis and fractures. Herein, we report a case of hip fragility fracture in a patient with indolent systemic mastocytosis and normal bone density.
UNASSIGNED: A 48-year-old man experienced a left femoral neck fracture after a fall. After a dose of oxycodone/hydromorphone postoperatively, he developed an anaphylactic reaction. Previously, he experienced a few other episodes of flushing, dizziness, and syncope precipitated by stress and alcohol. His examination was notable for pink and brown macules on his chest, back, arms, and legs. His laboratory test revealed a markedly elevated tryptase level of 171 ng/mL (<11 ng/mL). Treatment including cetirizine, montelukast, and ranitidine controlled his symptoms. His bone density test result was normal. Ten months after hip surgery, his c-terminal telopeptide of collagen type 1 and bone-specific alkaline phosphatase levels significantly increased. The bone scan demonstrated diffusely increased radiotracer uptake throughout the osseous structures. Given high bone turnover and the prior hip fracture, he received zoledronic acid yearly for 3 years, and no further fractures have occurred.
UNASSIGNED: The case is unusual as the fracture occurred despite normal bone density and significant osteosclerosis, which was previously considered protective against fractures. Additionally, rather than the spine, the fracture occurred in the hip, which is an uncommon site for mastocytosis-induced fractures.
UNASSIGNED: Mastocytosis is a rare cause of osteoporosis, and it is important to keep this condition in the differential diagnosis of osteoporosis, particularly when the fracture presentation is atypical.

UNASSIGNED: Idiopathic osteosclerosis (IO) is an area of enlarged bone production in the jaw that usually appears radiopaque and round, elliptical, or irregular in shape. Condensing osteitis (CO) is a focalized osseous reaction leading to periapical sclerotic bone growth.
UNASSIGNED: The aim of this study was to investigate the prevalence, localization, shape, and dental relationship of IO and CO in a group of Lebanese patients and to correlate these findings to age and gender.
UNASSIGNED: 520 digital panoramic radiographs of patients (215 men and 305 women) ranging in age from 18 to 77 (mean age 40.89 years) who visited the Faculty of Dental Medicine, Lebanese University, for dental treatment were included in this study and assessed for IO and CO. The prevalence of the two lesions according to gender and age, as well as their localization, and dental relationship, were recorded and saved in an Excel sheet.
UNASSIGNED: Among the 520 radiographs, 47 (9%) showed IO, and 30 (5.8%) showed CO. Both lesions are more frequent among females in their third decade and are essentially found in the mandible, mainly in relation to the root apices.
UNASSIGNED: Within the limits of this study, we concluded that in our sample of the Lebanese population, the prevalence of IO and CO is low and supports the theory that IO can be defined as developmental variations of normal bony architecture unrelated to a local stimulant, and CO could be considered reactive bone formations related to pulpitis, deep restoration, or caries.