3个肝豆状核变性家系的分子遗传学分析及临床运用研究

Molecular genetic analysis of three families with Wilson’s disease (WD)

目的探讨运用基因分析协助快速诊断、精准治疗肝豆状核变性(Wilson’s disease,WD)的价值。方法临床上收集、鉴定3个无血缘关系的常染色体隐性WD家系,抽取家系成员的外周血样本并提取基因组DNA;利用Sanger测序分别对3个家系先证者的WD致病基因ATP7B的全部21个外显子以及外显子-内含子交接区域进行突变检测;结合文献分析突变基因在不同种族的突变率,高频突变基因型与临床表型、发病早晚、病情严重程度的关系;根据基因型制定"基因导向型"治疗方案,评估患者1年后的疗效。结果 WD具有临床表型的异质性和遗传异质性;家系1中发现ATP7B的2个复合杂合突变c.2333G>T(p.R778L)、c.2975C>T(p.P992L);家系3中发现ATP7B的1个杂合突变p.R778L,家系3可能存在还未发现的ATP7B基因突变;家系2未能在遗传学上确定致病原因,提示可能存在还未发现的新的WD致病基因或常规测序手段无法发现的ATP7B基因突变;根据基因型制定"基因导向型"治疗方案,对家系1和家系3的患者具有有效的治疗效果。结论基于ATP7B的基因分析断有助于快速确诊肝豆状核变性,"基因导向型"治疗方案成功运用为该疾病的精准治疗提供了一定的依据,也为分子遗传学技术临床运用的推广和普及奠定了基础。

Objective To discuss the value of gene diagnosis in the rapid diagnosis and accurate treatment of Wilson’s disease. Methods In our research, we studied three non-consanguineous Chinese families from Hubei province. All these three pedigrees were diagnosed with theautosomal inheritant disorder of WD. We extracted DNA samples from the three probands and anplyfied all the exons and intron-exon boundary sequences of theATP7 B. And then, we subjected these sequences to the Sanger sequencing. The mutation rate of mutant genes in different races and the relationship between high frequency mutant genotypes and clinical phenotypes, onset time and severity of disease were analyzed. A "gene oriented" treatment regimen was developed according to the genotype, and the patient’s efficacy was evaluated after one year.Results There were two heterozygous mutations c.2333 G>T(p.R778 L), c.2975 C>T(p.P992 L) in family 1. There was heterozygous mutation c.2333 G>T(p.R778 L) in family 3, and there might be another undetected pathogenic mutation of ATP7 B gene in family 3. In family 2, there was no varation in ATP7B, which suggested that the potential of other pathogenic genes of WD might exist. According to the genotype, the "gene oriented" treatment plan was developed, and the therapy was certified efficientfor the patients of family 1 and family 3.Conclusion Gene diagnosis based on ATP7 B was conducive to the rapid diagnosis of Wilson’s disease, and the successful application of "gene oriented" treatment scheme provided a reliable basis for the accurate treatment of the disease, and also laid a foundation for the promotion and popularization of clinical application of molecular genetics technology.