- 學位論文
尋找MRKH症候群可能之基因決定因子
Searching for the genetic determinants of Mayer-Rokitansky-Kuester-Hauser (MRKH) syndrome
摘要
臨床上造成女性原發型無月經(Primary amenorrhea)的第二常見原因：MRKH 症候群(Mayer-Rokitansky-Kuester-Hauser syndrome)，此病主要影響女性生殖系統，造成陰道及子宮的發育不全，有時也會伴隨其他病徵，發生率約為1/4000~5000，患者染色體通常為正常核型46, XX，至今尚未發現致病基因。目前有部分文獻顯示此症有家族性關聯，支持此病屬於多基因遺傳模式，但其遺傳外顯率的不完全性(incomplete degree of penetrance)及遺傳表現度的變異性(variable expressivity)，導致此病成為一個不典型的體染色體顯性遺傳模式。 關於此症的突變位點跟致病基因，一直以來有很多臆測，有些想法已被證實沒有臨床意義或無直接相關性，有些變異則尚待確認，某些片段的變異更是屢被提出，2011年時，有研究表示此症患者身上及家族中有一些重複性的拷貝數變異(Copy number variants,簡稱CNVs)發生率偏高(14%)。 肇因於人類基因解碼完成，基因研究有了強大的資料庫做為後盾，再加上基因檢測技術及相關電腦統計軟體的快速進展，次世代基因定序(Next Generation sequencing,簡稱NGS)系統跟基因晶片技術也愈趨成熟，許多以往不容易發現的基因缺損現在都能被偵測到。 本研究主要期望能夠從CNVs的部份尋找MRKH 症候群的基因決定因子。 藉由臨床門診收集MRKH 症候群的個案，利用人類全外顯子定序(Whole Exome Sequencing,簡稱WES)以及晶片偵測CNVs，兩者交叉比對，尋找與此症可能有所關聯的變異點，最後找出兩個loss-of-function的CNVs和四個基因可能和MRKH syndrome有關，HNRNPCL1、LOC649330 和 OR4M2同時有兩位以上的個案發生缺失變異點，OR2T2則是有超過兩個以上的變異點存在。希冀此研究結果能解決MRKH 症候群的某些疑問，未來能應用於臨床諮詢，甚至更進一步將基因醫學代入實際醫療，改善現今MRKH syndrome的醫療模式及生育計畫。
並列摘要
Mayer-Rokitansky-Kuester-Hauser syndrome (MRKH Syndrome) is the second most common cause of primary amenorrhea. The incidence of MRKH syndrome has been estimated as 1 in 4000-5000 female births. It is characterized by congenital aplasia of the uterus and the vagina in women showing normal development of secondary sexual characteristics and a normal 46, XX karyotype. The majority of cases appears to be sporadic, however, family cases have also been described. The mode of inheritance seems to be autosomal dominant with an incomplete degree of penetrance and variable expressivity. The etiology has remained quite unclear until now. There are lots of hypothesis of the mutation site and associated gene about MRKH syndrome. Some variants that often investigated still need to be confirmed. In 2011, reports show there is high incidence (14%) of recurrent copy number variants (CNVs) in patients with MRKH syndrome. Recent advances in Next Generation Sequencing (NGS) and array technologies have brought a paradigm shift in how medical researchers investigate both rare and common human disorders. The genetic association of MRKH syndrome was analyzed over few years. However, their role in MRKH syndrome has not been subsequently demonstrated. This is also the first report of NGS application in recent MRKH syndrome study. In this study, 5 patients with MRKH syndrome were included, and were selected by uterine and vaginal agenesis. To explore the genetic determinants of MRKH syndrome, we performed Whole Exome Sequencing (WES) and SNP Array 6.0 in 5 cases. We could delineate two relevant chromosomal regions (1p36.21: chr1:12883040-12925851 and 15q11.2: chr15:22357379-22384101) and suggest that HNRNPCL1、LOC649330、OR4M2 and OR2T2 are candidate genes for MRKH syndrome. Each of HNRNPCL1、LOC649330 and OR4M2 has been found mutation within more than 2 cases. There were over 2 loss-of-function deletion site in OR2T2. These findings would help improve genetic testing, treatment and counseling of MRKH syndrome.