Autosomal dominant osteopetrosis type Ⅱ: 2 cases report and literature review / 中华内分泌代谢杂志

Osteosclerosis is a rare hereditary bone metabolic disease, characterized by increased bone mass and density caused by bone resorption disorders, and any abnormal mutation involving osteoclast maturation or function will lead to the occurrence of osteopetrosis. Clinically, the prevalence of autosomal dominant osteopetrosis type Ⅱ(ADO-Ⅱ) is higher than that of other types of osteopetrosis, which involves multiple systems such as endocrine, bone, blood, nerve, ear-nose-throat, and oral cavity. Disease progression is insidious and easily overlooked, and there is no standard treatment. This article summarizes the clinical characteristics, examination data, diagnosis and treatment process of the two patients, analyzes multi-system symptoms, pathogenesis and treatment principles of the disease to improve the management of patients with ADO-Ⅱ.

Genetic Analysis of CLCN7 in an Old Female Patient with Type II Autosomal Dominant Osteopetrosis

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.

A paradoxical presentation of rickets and secondary osteomyelitis of the jaw in Type II autosomal dominant osteopetrosis: Rare case reports.

Osteopetrosis is a rare genetic bone disorder arising due to a defect in the differentiation or function of osteoclast which results in a generalized increase in bone mass. Osteomyelitis is one of the most common complications because of decreased bone marrow function and compromised blood supply. Radiologist plays a vital role in diagnosing osteopetrosis. Here, we present two cases of autosomal dominant osteopetrosis Type II (ADO II) with secondary osteomyelitis changes which were reported to our department. One of these two cases presented with secondary osteomyelitis in both maxilla and mandible and features of rickets, which is very rarely seen in ADO II. To the best of our knowledge, the presentation of rickets with ADO is the first of its kind to be reported. In this paper, we describe the clinical and radiological features leading to the diagnosis of ADO in these two patients. Further, a review of the literature regarding ADO is discussed.