The correlation of intracranial parenchymal calcium score and the severity of neurological clinical presentation in carbonic anhydrase deficiency type 2.

Background: Carbonic anhydrase type II deficiency (CAII-D) syndrome is a rare autosomal recessive genetic disorder characterized by osteopetrosis, renal tubular acidosis, and brain calcifications. Understanding the clinical and radiological features of CAII-D is key to effective management.

Aim: This study aimed to comprehensively analyze and measure intracranial parenchymal calcium score in pediatric CAII-D in relation to the severity of neurological clinical presentation.

Osteoprotegerin secretion and its inhibition by RANKL in osteoblastic cells visualized using bioluminescence imaging.

Bone remodeling is regulated by the interaction between receptor activator of nuclear factor kappa-B ligand (RANKL) and its receptor RANK on osteoblasts and osteoclasts, respectively. Osteoprotegerin (OPG) is secreted from osteoblasts and inhibits osteoclast differentiation by acting as a decoy receptor for RANKL. Despite its importance, the mechanism underlying the secretion of OPG remains poorly understood.

Therapeutic targeting of Wnt antagonists by small molecules for treatment of osteoporosis.

Wnt signaling is one of the key regulators of bone development and homeostasis. Wnt signaling regulates key biological events, including stem cell fate and osteoblast and osteoclast activity, leading to the maintenance of bone mass and strength. Wnt ligands are secreted glycoproteins that bind to Frizzled (FZD) receptors and their coreceptors, lipoprotein receptor-related proteins-5/6 (LRP5/6).

Integrin α2 is an early marker for osteoclast differentiation that contributes to key steps in osteoclastogenesis.

Introduction: Osteoclasts determine bone tissue turnover. Their increased activity causes osteoporosis, their dysfunction osteopetrosis.

Methods And Results: Murine monocytic ER-Hoxb8 cells differentiate into OCs upon treatment with M-CSF and RANKL and upregulate the collagen-binding integrin α2β1 distinctly earlier than other OC markers, such as the OC-associated receptor, OSCAR.

Malignant osteopetrosis of infancy: A case report.

Introduction: Osteopetrosis is a genetic bone disease whose main feature is the function of osteoclasts. This rare disorder affects one in every 250,000 live births. In terms of pathophysiology, osteopetrosis is divided into four types from mild to severe forms of the disease.

SNX10 regulates osteoclastogenic cell fusion and osteoclast size in mice.

Bone-resorbing osteoclasts (OCLs) are formed by differentiation and fusion of monocyte precursor cells, generating large multinucleated cells. Tightly regulated cell fusion during osteoclastogenesis leads to formation of resorption-competent OCLs, whose sizes fall within a predictable physiological range. The molecular mechanisms that regulate the onset of OCL fusion and its subsequent arrest are, however, largely unknown.

Transmembrane protein 53 craniotubular dysplasia (OMIM # 619727): The skeletal disease and consequent blindness of this new disorder.

Craniotubular dysplasia, Ikegawa type (OMIM #619727) denotes the autosomal recessive skeletal disease identified in 2021 featuring blindness acquired in childhood. Five young members of four Indian families harbored a homozygous indel within TMEM53 (OMIM *619722), the gene that encodes transmembrane protein 53 (TMEM53). When intact, TMEM53 spans the nuclear envelope of osteoprogenitor cells, dampens BMP-SMAD signaling, and thereby slows bone formation.

Multisystem disorder associated with a pathogenic variant in CLCN7 in the absence of osteopetrosis.

Background: We clinically and genetically evaluated a Taiwanese boy presenting with developmental delay, organomegaly, hypogammaglobulinemia and hypopigmentation without osteopetrosis. Whole-exome sequencing revealed a de novo gain-of-function variant, p.Tyr715Cys, in the C-terminal domain of ClC-7 encoded by CLCN7.

Endoscopic endonasal optic nerve decompression in children younger than 2 years old with congenital optic canal stenosis: illustrative cases.

Background: Congenital optic canal stenosis causing compressive optic neuropathy is a rare disorder that presents unique diagnostic and treatment challenges. Endoscopic endonasal optic nerve decompression (EOND) has been described for optic nerve compression in adults and adolescents but has never been reported for young children without pneumatized sphenoid sinuses. The authors describe preoperative and intraoperative considerations for three patients younger than 2 years of age with congenital optic canal stenosis due to genetically confirmed osteopetrosis or chondrodysplasia.