Introduction: Primary hyperparathyroidism (PHPT) is a common disorder that typically leads to increased bone turnover and reduced bone mineral density (BMD). Osteopetrosis, in contrast, is a rare, inherited disorder of defective osteoclast function, resulting in diffusely sclerotic but structurally fragile bones. The coexistence of both conditions is rare and can significantly alter the expected skeletal phenotype of PHPT. Case: We report a 77-year-old female with a previous history of resected ovarian carcinoma in remission, chronic iron deficiency anemia, and hypothyroidism. During a hospital admission for a lacunar infarct, an incidental finding of sclerotic skull lesions on computed tomography (CT) brain prompted further investigation. She had no history of fractures, hearing impairment, or family history of parathyroid or bone disorders. Biochemistry revealed parathyroid-dependent hypercalcemia with normal renal function. Bone turnover markers showed a normal resorption marker (BCTx) but an elevated formation marker (P1NP), with a mildly raised alkaline phosphatase. A sestamibi scan localized a probable left upper parathyroid adenoma, despite a negative neck ultrasound. Skeletal survey unexpectedly revealed widespread osteosclerosis of the skull, spine, and long bones, with a markedly elevated BMD on densitometry. Review of prior imaging confirmed that these sclerotic changes predated her current presentation, having been present on CTs from over a decade ago. Recurrent malignancy was excluded with repeat imaging and tumor markers. A diagnosis of PHPT secondary to parathyroid adenoma, coexisting with underlying, previously unrecognized osteopetrosis, was made. The patient declined both recommended parathyroidectomy and genetic studies. Conclusion This case demonstrates a rare coexistence of two pathologies with opposing effects on bone metabolism. The underlying osteopetrosis, characterized by defective osteoclasts, likely rendered the patient’s osteoclasts resistant to the catabolic effects of elevated PTH. This resulted in an atypically normal bone resorption marker and an unexpectedly high BMD, despite the diagnosis of PHPT.
Bone Density' ; Hyperparathyroidism ; Primary Osteopetrosis

OBJECTIVES: To study the clinical and genetic characteristics of osteopetrosis (OPT) in children. METHODS: A retrospective analysis was performed on the clinical data of 14 children with OPT. Whole-exome sequencing was used to detect pathogenic genes, and clinical phenotypes and genotypic features were summarized. RESULTS: Among the 14 children (10 males and 4 females), the median age at diagnosis was 8 months. Clinical manifestations included systemic osteosclerosis (14 cases, 100%), anemia (12 cases, 86%), infections (10 cases, 71%), thrombocytopenia (9 cases, 64%), hepatosplenomegaly (8 cases, 57%), and developmental delay (5 cases, 36%). Malignant osteopetrosis (MOP) cases had lower platelet counts, creatine kinase isoenzyme, and serum calcium levels, but higher white blood cell counts, lactate dehydrogenase, and alkaline phosphatase levels compared to non-MOP cases (P<0.05). Genetic testing identified 15 variants in 12 patients, including 8 variants in the CLCN7 gene (53%), 6 in the TCIRG1 gene (40%), and 1 in the TNFRSF11A gene (7%). Three novel CLCN7 variants were identified: c.2351G>C, c.1215-43C>T, and c.1534G>A. All four patients with TCIRG1 variants exhibited MOP clinical phenotypes. Of the seven patients with CLCN7 variants, 4 presented with intermediate OPT, 2 with benign OPT, and 1 with MOP. CONCLUSIONS Clinical phenotypes of OPT in children are heterogeneous, predominantly involving CLCN7 and TCIRG1 gene variants, with a correlation between clinical phenotypes and genotypes.
Humans ; Osteopetrosis/genetics* ; Male ; Female ; Infant ; Child, Preschool ; Retrospective Studies ; Vacuolar Proton-Translocating ATPases/genetics* ; Child ; Chloride Channels/genetics* ; Mutation ; Receptor Activator of Nuclear Factor-kappa B

Objective: To investigate the clinical presentation and genetic characteristics of malignant infantile osteopetrosis. Methods: This was a retrospective case study. Thirty-seven children with malignant infantile osteopetrosis admitted into Beijing Children's Hospital from January 2013 to September 2022 were enrolled in this study. According to the gene mutations, the patients were divided into the CLCN7 group and the TCIRG1 group. Clinical characteristics, laboratory tests, and prognosis were compared between two groups. Wilcoxon test or Fisher exact test were used in inter-group comparison. The survival rate was estimated with the Kaplan-Meier method and the Log-Rank test was used to compare the difference in survival between groups. Results: Among the 37 cases, there were 22 males and 15 females. The age of diagnosis was 0.5 (0.2, 1.0) year. There were 13 patients (35%) and 24 patients (65%) with mutations in CLCN7 and TCIRGI gene respectively. Patients in the CLCN7 group had an older age of diagnosis than those in the TCIRGI group (1.2 (0.4, 3.6) vs. 0.4 (0.2, 0.6) years, Z=-2.60, P=0.008). The levels of serum phosphorus (1.7 (1.3, 1.8) vs. 1.1 (0.8, 1.6) mmol/L, Z=-2.59, P=0.010), creatine kinase isoenzyme (CK-MB) (457 (143, 610) vs. 56 (37, 82) U/L, Z=-3.38, P=0.001) and the level of neutrophils (14.0 (9.9, 18.1) vs. 9.2 (6.7, 11.1) ×10⁹/L, Z=-2.07, P=0.039) at diagnosis were higher in the CLCN7 group than that in the TCIRG1 group. However, the level of D-dimer in the CLCN7 group was lower than that in the TCIRGI group (2.7 (1.0, 3.1) vs. 6.3 (2.5, 9.7) μg/L, Z=2.83, P=0.005). After hematopoietic stem cell transplantation, there was no significant difference in 5-year overall survival rate between the two groups (92.3%±7.4% vs. 83.3%±7.6%, χ²=0.56, P=0.456). Conclusions: TCIRGI gene mutations are more common in children with osteopetrosis. Children with TCIRGI gene mutations have younger age, lower levels of phosphorus, CK-MB, and neutrophils and higher level of D-dimer at the onset. After hematopoietic stem cell transplantation, patients with CLCN7 or TCIRGI gene mutations have similar prognosis.
Child ; Male ; Female ; Humans ; Osteopetrosis/therapy* ; Retrospective Studies ; Prognosis ; Genes, Recessive ; Phosphorus ; Chloride Channels/genetics* ; Vacuolar Proton-Translocating ATPases/genetics*

A case of SNX10 gene mutation in a patient with infantile malignant osteopetrosis (IMO) was admitted to Department of Pediatrics, Third Xiangya Hospital, Central South University. The patient had the symptom of anemia, hepatosplenomegaly and growth retardation. The X-ray examination suggested extensive increase of bone density throughout the body, which was clinically diagnosed as IMO. The homozygous mutation of SNX10 gene c.61C>T was found via gene sequencing. We reviewed the relevant literatures and found that anemia, visual and hearing impairment, hepatosplenomegaly are the main clinical symptoms of IMO, SNX10 gene mutation is a rare cause of IMO, and hematopoietic stem cell transplantation is an effective treatment.
Bone Density ; Child ; Hematopoietic Stem Cell Transplantation ; Humans ; Mutation ; Osteopetrosis/genetics* ; Sorting Nexins/genetics*

Identification of certain abnormalities of the chest wall can be extremely helpful in correctly diagnosing a number of syndromic conditions and systemic diseases. Additionally, chest wall abnormalities may sometimes constitute diagnoses by themselves. In the present pictorial essay, we review a number of such conditions and provide illustrative cases that were retrospectively identified from our clinical imaging database. These include pentalogy of Cantrell, Klippel-Feil syndrome, cleidocranial dysplasia, Poland syndrome, osteopetrosis, neurofibromatosis type 1, Marfan syndrome, Gardner syndrome, systemic sclerosis, relapsing polychondritis, polymyositis/dermatomyositis, ankylosing spondylitis, hyperparathyroidism, rickets, sickle cell anemia, thalassemia, tuberculosis, septic arthritis of the sternoclavicular joint, elastofibroma dorsi, and sternal dehiscence.
Anemia, Sickle Cell ; Arthritis, Infectious ; Cleidocranial Dysplasia ; Diagnosis ; Gardner Syndrome ; Hyperparathyroidism ; Klippel-Feil Syndrome ; Marfan Syndrome ; Neurofibromatosis 1 ; Osteopetrosis ; Pentalogy of Cantrell ; Poland Syndrome ; Polychondritis, Relapsing ; Retrospective Studies ; Rickets ; Scleroderma, Systemic ; Spondylitis, Ankylosing ; Sternoclavicular Joint ; Thalassemia ; Thoracic Wall ; Tuberculosis

BACKGROUND: Treating patients with osteopetrosis is very challenging even in very skilled surgeons with many experiences. We present an account of 5 patients treated for hip fracture related problems occurring throughout their life due to this disease. Difficulties encountered during their treatment prompted us to present some general management principles. METHODS: From January 2003 to December 2016, 5 patients with osteopetrosis (9 hips; 3 men, 2 women), who underwent operative or conservative treatment were retrospectively reviewed. We evaluated their clinical features and rate of union, malunion and post-operative infection. RESULTS: Four of 5 patients (80%) suffered bilateral fracture, and 8 of 9 fractures (89%) are transverse and occurred at subtrochanteric area resulted from minor trauma. Among 9 hips, surgery was performed in seven hips. Nonunion were found in 3 hips (33%), malunion in 1 hip (11%) and oteomyelitis was developed in 2 hips (22%) at a median of 8.1 years. CONCLUSIONS: Clinical features of hip fracture in osteopetrosis are very similar to atypical subtrochanteric femoral fractures. Patients should be informed of the possibilities of several anticipated complications including the risk of nonunion and infection after surgery.
Femoral Fractures ; Fracture Fixation, Internal ; Hip Fractures ; Hip ; Humans ; Male ; Osteopetrosis ; Retrospective Studies ; Surgeons

BACKGROUND: Type II autosomal dominant osteopetrosis (ADO II) is a rare genetically heterogeneous disorder characterized by osteosclerosis and increased bone mass, predominantly involving spine, pelvis, and skull. It is closely related to functional defect of osteoclasts caused by chloride voltage-gated channel 7 (CLCN7) gene mutations. In this study, we aimed to identify the pathogenic mutation in a Korean patient with ADO II using whole exome sequencing. METHODS: We evaluated the clinical, biochemical, and radiographic analysis of a 68-year-old woman with ADO II. We also performed whole exome sequencing to identify pathogenic mutation of a rare genetic disorder of the skeleton. Moreover, a polymorphism phenotyping program, Polymorphism Phenotyping v2 (PolyPhen-2), was used to assess the effect of the identified mutation on protein function. RESULTS: Whole exome sequencing using peripheral leukocytes revealed a heterozygous c.296A>G missense mutation in the CLCN7 gene. The mutation was also confirmed using Sanger sequencing. The mutation c.296A>G was regarded to have a pathogenic effect by PolyPhen-2 software. CONCLUSION: We detect a heterozygous mutation in CLCN7 gene of a patient with ADO II, which is the first report in Korea. Our present findings suggest that symptoms and signs of ADO II patient having a c.296A>G mutation in CLCN7 may appear at a very late age. The present study would also enrich the database of CLCN7 mutations and improve our understanding of ADO II.
Aged ; Exome ; Female* ; Humans ; Korea ; Leukocytes ; Mutation, Missense ; Osteoclasts ; Osteopetrosis* ; Osteosclerosis ; Pelvis ; Skeleton ; Skull ; Spine

Osteopetrosis is characterized by impaired osteoclast function and increased bone density. Infantile osteopetrosis is a severe form of the disease and has characteristics such as diffusely sclerotic skeleton, pancytopenia, cranial nerve entrapment, infection susceptibility, and abnormal craniofacial appearance. Patients with infantile osteopetrosis often experience developmental delay, and may have a short life span.A 14-month-old girl with osteopetrosis presented to the department of pediatric dentistry. Incipient caries on deciduous incisors were observed. The patient revisited 4 years of age. Besides medical problems, oral complications such as growth retardation, narrow upper arch, crowding, dental caries, and abnormal tooth development were observed. After consultation with her pediatrician, dental treatments were performed on the deciduous molars under sedation after a prophylactic antibiotic injection. At a periodic follow-up, multiple deciduous teeth were treated and extracted, and oral-rehabilitation with a removable partial denture was initiated.Patient with osteopetrosis are highly susceptible to infection because of their compromised immune system and problems associated with wound healing that lead to osteomyelitis or sepsis development.Active participation in dental care for sugar intake management and proper oral hygiene are obligatory.
Bone Density ; Cranial Nerves ; Crowding ; Dental Care ; Dental Caries ; Denture, Partial, Removable ; Female ; Follow-Up Studies ; Humans ; Immune System ; Incisor ; Infant ; Molar ; Oral Hygiene ; Osteoclasts ; Osteomyelitis ; Osteopetrosis ; Pancytopenia ; Pediatric Dentistry ; Sepsis ; Skeleton ; Tooth ; Tooth, Deciduous ; Wound Healing

OBJECTIVETo detect potential mutation of the TCIRG1 gene in a boy with infantile malignant osteopetrosis.

METHODSTarget sequence capture and next-generation sequencing were applied for the proband and his parents to identify the causative mutation, and Sanger sequencing was used to verify the suspected mutation.

RESULTSThe proband manifested at 4 months of age with symptoms including anemia, thrombocytopenia, hepatosplenomegaly, and cephalus quadratus. X-ray revealed generalized increased bone density. A novel compound heterozygous mutation, c.796G to T (p.E266X) and c.1372G to A (p.G458S), were identified in the boy. His father and grandmother also carried the c.796G to T (p.E266X) mutation, and his mother carried the c.1372G to A (p.G458S) mutation. Neither mutation was found in the PubMed and ClinVar databases.

CONCLUSIONThe novel compound heterozygous mutation c.796G to T (p.E266X) and c.1372G to A (p.G458S) probably underlies the disease in the proband. Above results may enrich the mutation spectrum of the TCIRG1 gene and provide new evidence for the molecular basis of infantile malignant osteopetrosis.

Adult ; Asian Continental Ancestry Group ; Base Sequence ; Humans ; Infant ; Infant, Newborn ; Infant, Newborn, Diseases ; genetics ; Male ; Middle Aged ; Molecular Sequence Data ; Mutation ; Osteopetrosis ; genetics ; Pedigree ; Vacuolar Proton-Translocating ATPases ; genetics

In general, bone homeostasis is maintained through the balance between bone formation and resorption. Disruption in this balance results in bone-related diseases such as osteopetrosis, osteoporosis, and rheumatoid arthritis. Often, enhanced osteoclastogenesis is followed by accelerated bone resorption that is induced by pro-inflammatory cytokines in osteoporosis or rheumatoid arthritis, and leads to bone destruction. In this review study, factors involved in osteoclast differentiation and function are discussed, and how the prevention of such factors is effective in ameliorating bone loss in osteoporosis or rheumatoid arthritis.
Arthritis, Rheumatoid ; Bone and Bones ; Bone Resorption ; Cytokines* ; Homeostasis ; Osteoclasts* ; Osteogenesis ; Osteopetrosis ; Osteoporosis