MUTATION IN THE CLCN7 GENE CAUSING AUTOSOMAL DOMINANT OSTEOPETROSIS TYPE Ⅱ: A CASE REPORT AND LITERATURE REVIEW

Abstract

Objective To analyze the mutation in the CLCN7 gene in a patient with autosomal dominant osteopetrosis type Ⅱ (ADOⅡ), and to improve clinical understanding of the disease. Methods The clinical data of a patient with ADOⅡ were collected, and the peripheral blood samples of the patient and his wife and daughter were collected. The exons in the CLCN7 gene were amplified using polymerase chain reaction (PCR). The products from the PCR amplification were purified, sequenced, and screened for mutation sites. Results The patient’s lower left posterior tooth region was swollen and painful, and the effect of anti-inflammatory treatment was not satisfactory. After admission, a curettage surgery for the left mandibular osteomyelitis combined with dead bone removal was performed under general anesthesia. During the surgery, the granulation tissue and dead bones in the left mandible diseased area were submitted for examination. The pathological diagnosis showed (mandibular bone marrow) chronic suppurative inflammation with granulation tissue proliferation and dead bone formation in the mandible. Gene testing revealed a missense mutation in exon 24 of the CLCN7 gene, namely the p.Arg743Trp mutation. After surgery, fluid infusion and anti-infective treatment were given. Upon discharge, the patient had a good general condition, with no swelling or pain in the left mandibular area; the incisions in the mouth healed well, and showing no bleeding. Conclusion The missense mutation of p.Arg743Trp in the CLCN7 gene can lead to ADOⅡ. This study can provide reference for genetic diagnosis and treatment of ADOⅡ in the local population in the future.

Keywords

• osteopetrosis|genetic testing|clcn7 gene|mutation|case reports