耳聋基因的胚胎植入前诊断

Preimplantation Genetic Diagnosis of Jereditary Hearing Loss

耳聋是人类最常见的遗传疾病之一,世界不同国家地区报告新生儿耳聋的发病率在1~3‰。在我国大概有2780万聋人,每年有3万多先天性耳聋的新生儿出生,之前有调查显示耳聋新生儿中有54.93%是由遗传因素造成。如此庞大的耳聋及突变基因携带者家庭很大一部分具有强烈的生育正常听力下一代的意愿。目前对于阻断耳聋向子代遗传,产前诊断技术是唯一的预防手段。但由于其有创、可能面临大月份引产等带来一定的伦理争议。对于耳聋这种非致死性遗传病,胚胎植入前诊断(preimplantation genetic diagnosis,PGD)是目前国际上主流的预防手段。因此我们亟需建立一种针对中国人群耳聋遗传病特点的,简便易行、可靠性高、成功率高的胚胎植入前诊断方法。成为耳聋三级预防体系的第一道关卡。本文系统回顾了单基因遗传病尤其是遗传性耳聋胚胎植入前诊断方法的发展历史和最新进展,阐述了胚胎活检、全基因组扩增、连锁分析、染色体扫描四个胚胎植入前诊断关键技术步骤的方法及新进展。

Hearing impairment is the most common neurosensory disorder in humans.The reported incidence ranges from 1 in 300 to 1 in 1000 children.In China,it has been estimated that there are a total of 27.8 million people with hearing loss and 30,000 babies are born with congenital hearing impairment every year.It was previously reported that in the Chinese population,the GJB2 and SLC26A4 gene mutations were the hotspots involved in inherited hearing impairment.At present,genetic testing has become available clinically and results in new ideas in prevention of deafness.In addition to genetic counselling and medical guidance,in the past 10 years,thousands of families received traditional invasive prenatal diagnostic procedures to determine whether the fetus carried deafness genes.The ethical dilemma brings pressure to geneticists.We are eager to develop an effective and convenient pre-implantation genetic diagnosis(PGD)procedure that can be expanded easily.In this paper,the history and new progress in pre-implantation genetic diagnosis for monogenic diseases,especially hereditary hearing loss,are summarized.The paper also elaborates on technical essentials of the PGD procedure,including embryo biopsy,whole genome amplification,chromosome screening and linkage analysis.