COL7A1基因嵌合突变分析及产前基因诊断在营养不良型大庖性表皮松解症家系中的研究

Dystrophic epidermolysis bullosa (DEB) is a genetic skin disease caused by mutations in the COL7A1 gene. There is no effective therapy. The recurrence risk for future offspring is much higher caused by gonadosomatic mosaicism than that by de novo mutations. Gonadosomatic mosaicism has a significant impact on clinical diagnosis and genetic counselling about the recurrence risk for future offspring. Missed diagnosis on gonadosomatic mosaicism leads to great harm. Therefore, how to confirm gonadosomatic mosaicism is quite important. There is lack of study on gonadosomatic mosaicism and further prenatal genetic diagnosis in DEB families. Our research has confirmed the existance of gonadosomatic mosaicism in DDEB parents with no phenotype. Further research should be continued on patients’ parents with no phenotype and patients with segmental, linear or plaque skin fragility disorder of DEB, using deep pyrosequencing and SNaPshot analysis on the prevalence of the COL7A1 mutant allele in peripheral blood samples, skin, oral mucosa, saliva samples, hairs globular cells, father sperm cells and other samples to find the prognosis differences before or after the zygotic mutation on DEB patients, to confirm the existance of gonadosomatic mosaicism, to improve efficiency and accuracy for the diagnosis of mosaic mutation and lay the foundation on genetic counseling and prenatal genetic diagnosis, promoting healthy birth and decreasing birth defect.

营养不良型大疱性表皮松解症（DEB）是一种由于COL7A1基因突变导致的遗传性皮肤病，目前无有效根治方法。生殖腺嵌合突变较自发突变导致的DEB其遗传风险率大大增加。在临床诊断和遗传风险咨询时，生殖腺嵌合现象的漏诊危害巨大。因此，如何证实生殖腺嵌合是很重要的。目前国内外对DEB家系生殖腺嵌合突变的研究及后续的产前诊断干预相对缺乏。本研究前期已证实，DDEB患者不发病父母可能存在生殖腺嵌合现象。进一步的研究针对患者表型正常的父母和有节段性、线性或斑块分布的DEB患者，选用深度焦磷酸测序和SNaPshot分析技术，测定外周血、皮肤、口腔黏膜、唾液、头发毛球细胞、父亲精细胞等样本中COL7A1基因突变比例，判断合子前后嵌合突变对患者预后的影响差异；明确是否存在生殖腺嵌合，旨在提高嵌合突变诊断效率和准确性，为此类患者遗传咨询和产前基因诊断奠定基础，优生优育，防止后代患病。

本研究首次发现并证实使用庆大霉素软膏（0.3%）可以治疗由COL17A1无义突变引起的JEB，提高患者皮损的愈合速度，减少起疱频率，诱导JEB患处基底膜带（BMZ）产生XVII型胶原（C17），显著改善患者生活质量，减轻日常护理压力。这一研究成果发表于The Journal of Dermatology上（IF=3.072）。本研究是中国最大样本量的EB研究，通过基于二代测序的测序包，成功检测出所有EB类型，包括单纯型EB（EBS）、交界型EB（JEB）、营养不良型EB（DEB）和Kindler型EB，并从中发现3个EB嵌合突变患者，从而证实二代测序技术能有效诊断EB。这一研究成果发表于Clinical Genetics（IF=3.578）上。.本项目成果作为主要申报内容获得2020年度华夏医学科技奖一等奖（第一完成单位）；2018年度中华医学会优秀研究生奖三等奖。.本项目共计发表标注本项目的SCI论文2篇（总计影响因子为6.65），举办全国性学术会议2次，参加国内学术交流10次以上，培养硕士研究生1名（已毕业）。