Screening copy number variations by array comparative genomic hybridization in 30 patients with congenital hypopituitarism.

目的：人脑垂体中受时空调控的转录因子基因突变可导致先天性垂体功能低下（CH）。由于已知的转录因子突变导致的CH患病率似乎很少见，CH的其他致病基因仍有待确定。由于CH的散发性，新生染色体重排可能是参与其病因学的分子机制之一，特别是在综合征型CH中。研究对象和方法：我们招募了88名日本CH患者（综合征型30例，非综合征型58例）。我们对30例综合征性CH患者进行了CGH阵列筛查，以确定拷贝数变异（CNVs）在该病病因学中的作用。结果：我们在一例孤立GH缺乏、腭裂和视盘拔罐的患者中发现了一个350kb的PAX6增强子区杂合缺失。对于所有患者，我们分析了pax6的所有编码外显子和侧翼内含子，并在一名表现出孤立GH缺乏症的非综合征性CH患者中发现了一个新的突变，即p. N116S。体外实验表明，N116S PAX6突变与PAX6结合元件的转激活能力受损相关，无显性负向效应。结论：PAX6是众所周知的眼睛发育调节因子，其在人类中的杂合突变可导致先天性眼睛异常，如无虹膜。本研究首次发现PAX6杂合突变与伴有或不伴有眼部畸形的CH患者相关。

Objective : Mutations in transcription factors genes, which are regulated spatially and temporally in the pituitary gland, result in congenital hypopituitarism(CH) in humans. The prevalence of CH attributable to known transcription factor mutations appears to be rare and other causative genes for CH would remain to be identified. Due to the sporadic occurrence of CH, de novo chromosomal rearrangements are conceivably representing one of the molecular mechanisms participating in its etiology, especially in syndromic CH.Subjects and Methods : We enrolled 88(Syndromic : 30, Non-syndromic 58) Japanese CH patients. We performed an array CGH screen of 30 syndromic CH patients to determine the role of copy number variations(CNVs) in the etiology of the disease.Results : We identified one heterozygous 350kb deletion of PAX6 enhancer region in one patient showing isolated GH deficiency, cleft palate, and optic disc cupping. For all patients, we analyzed all coding exons and flanking introns ofPAX6 and identified a novel mutation, namely p. N116S in one non-syndromic CH patient showing isolated GH deficiency. In vitro experiments showed that N116S PAX6 mutation was associated with an impairment of the transactivation capacities of PAX6 binding element, without any dominant-negative effects.Conclusions : PAX6 is a well-known regulator of eye development, and its heterozygous mutations in humans cause congenital eye anomalies such as aniridia. This study showed, for the first time, that heterozygous PAX6 mutations are associated with CH patients with or without ocular malformation.