AKT1基因嵌合性体细胞突变导致Proteus综合征临床研究

A clinical study of Proteus syndrome caused by a mosaic somatic mutation in AKT1 gene

目的分析1例罕见的Proteus综合征患者的临床特征,并进行致病基因突变研究和手术治疗干预,同时复习相关文献。方法详细收集Proteus综合征患者临床资料,进行生化及放射学检查等辅助检查,采集患者外周血及病变指骨手术样本,分别抽提DNA进行AKT1基因的Sanger测序,并在患者、其父母及250名健康对照者外周血中进行致病基因突变验证。针对患者的受累肢体进行手术矫形。结果患者临床表现为右侧肢体进行性过度生长,脊柱侧弯且伴有脑形结缔组织痣和双下肢静脉曲张。患者病变骨组织DNA携带AKT1基因杂合突变(c.49G>A),患者、其父母及250名健康对照者外周血基因组DNA未检测到该突变。术后患者肢体运动功能明显改善。结论一侧肢体过度生长伴脑形结缔组织痣是Proteus综合征的显著特征,AKT1基因嵌合性体细胞突变为Proteus综合征的致病基因突变之一,矫形手术可能是改善症状的较好手段。

Objective Proteus syndrome is a rare disease. The aim of the present study was to analyze the clinical characteristics and gene mutations of Proteus syndrome with a case report and relevant literature review. Methods Clinical data of the patient with Proteus syndrome were collected in detail and biochemical measurements and radiological examinations were conducted. Tissues from phalanges with lesions were obtained to extract DNA, and Sanger sequencing of AKT1 gene was carried on. The pathogenic mutation was further tested in peripheral blood samples of the patient, his parents and 250 healthy volunteers. Orthopaedic surgery was performed on the affected limbs of the patient. Results The patient was presented with progressive overgrowth of the right extremity, scoliosis, cerebral connective tissue nevus and lower extremity venous. A heterozygous mutation of AKT1 gene (c. 49G>A) was identified in DNA extracted from the affected bone tissue of the patient, but not be found in genomic DNA of peripheral blood samples from the patient, his parents and 250 healthy volunteers. Movement function of the affected limb improved significantly after the operations. Conclusions The prominent features of Proteus syndrome are overgrowth of one extremity and cerebral connective tissue nevus. A mosaic somatic mutation of AKT1 gene is one of the pathogenic mutations for Proteus syndrome, and orthopedic surgery may be a good way to improve symptoms of the disease.