目的 探讨婴儿神经轴索营养不良(INAD)的临床和PLA2G6基因突变特征。方法 回顾分析1例经基因检 测确诊的INAD患儿的临床资料。结果 患儿,男, 1岁9个月,主要临床表现为精神运动发育倒退、肌张力减低、病理征 阳性;肌电图显示神经源性损害; 1岁时查头颅磁共振成像(MRI)未见异常, 1岁9个月复查头颅MRI显示小脑萎缩。应 用目标序列捕获和第二代测序检测发现,患儿PLA2G6基因外显子区域两处杂合突变点c.1933C>T和c.911T>C,分别引 起氨基酸变化p.R645X和p.L304P;Sanger测序验证结果显示2个突变分别来源于母亲和父亲,为复合杂合突变。c.1933C>T 位点已报道为致病突变,c.911T>C为首次报道,且在正常人群中未检测到。结论 二代测序技术可准确检测PLA2G6基 因突变,可作为INAD的首选确诊手段。本报道扩大了中国INAD患者的基因突变谱。
Objective To explore the clinical and PLA2G6 gene mutation characteristics of the infantile neuroaxonal dystrophy (INAD). Method The clinical data of INAD diagnosed by gene detection were reviewed and analyzed. Results A male child aged 1 year and 9 months had the main clinical manifestations of psychomotor retrogression, muscular dystonia, and positive pathological signs. Electromyography showed neurogenic damage. No abnormality was found in MRI at the age of one year. However, cerebellar atrophy was found by MRI at the age of 1 year and 9 months. Target sequence and second generation sequencing revealed that two heterozygous mutations, c.1933C>T and c.911T>C, in the exon region of PLA2G6 gene, caused amino acid changes of p.R645X and p.L304P, respectively. The results of Sanger sequencing showed that 2 mutations were derived from mother and father and are compound heterozygous mutation. The c.1933C>T site has been reported to be a pathogenic mutation, while c.911T>C is first reported and has not been detected in the normal population. Conclusion The two generation sequencing technology can accurately detect PLA2G6 gene mutation and thus can be used as the first choice for diagnosis of INAD. This report has expanded the gene mutation spectrum of Chinese INAD patients.