Anopthalmia Spectrum Disorders

描述（由申请人提供）：无眼症或眼睛缺失，在5，000至10，000人中发现1例，由于导致视力受损，是一种毁灭性的出生缺陷。无眼症与小眼症（小眼睛）和缺损（脉络膜裂或视神经裂闭合失败）密切相关。我们研究了一名患有严重小眼症的男性患者，该患者在染色体18q22.1处存在新型染色体缺失。我们发现了18q22.1缺失的基因之一TXNDC 10与眼的发育有关。原位杂交结果显示，Txndc 10在发育中的小鼠眼的视网膜神经上皮和透镜上皮中表达。我们对66名无眼或小眼患者的TXNDC 10进行了重新测序，发现c.260G>A，预测在一名无关的小眼和视网膜缺损患者中存在错义替换p.R39Q。我们使用针对斑马鱼Txndc 10同源基因Zgc 110025的反义morpholinos，以显示morphant幼虫具有小眼症和缺损。与Pax 2的原位杂交显示，与对照组相比，变形细胞的脉络膜裂染色增加，表明Pax 2失调参与了缺损的形成。在周边视网膜中，变形视网膜具有增加的抗组蛋白H3染色，并且我们在变形视网膜中观察到较少的迟分化细胞类型。共注射人野生型TXNDC 10 mRNA与吗啉代挽救了吗啡肽表型，而共注射人TXNDC 10/（p.R39Q）突变体mRNA与吗啉代没有。我们的研究结果表明，TXNDC 10的单倍不足扰乱眼睛的发育。我们建议从两个方向继续我们对TXNDC 10的研究。我们假设Txndc 10可能是腹侧视网膜发育的已知途径的一部分，并希望使用斑马鱼来确定Zgc 110025是否与其他已知的参与脉络膜裂闭合和腹侧视网膜形成的基因相互作用，如Vax 1，Vax 2和Shh（Syu）。我们将使用原位杂交，双注射反义morpholinos和mRNA拯救实验来实现这一目标。我们的目的是试图揭示Txndc 10影响眼发育的机制。其次，我们建议建立一个Txndc 10功能丧失的小鼠模型，以检查遗传无效模型中的眼表型，而不是仅部分丧失基因功能的动物模型。我们假设Txndc 10功能的丧失将产生具有小眼症和缺损的小鼠，并且我们将使用所得到的敲除小鼠来检查Txndc 10无效动物的眼形态，并进行表达阵列以评估Txndc 10无效小鼠和野生型同窝仔之间的基因表达差异。我们的最终目标是改善现有的知识，所需的腹侧视网膜形成和脉络膜裂关闭的基因，使人类患者无眼症和相关的眼睛缺陷，可以提供改进的遗传咨询和测试。 公共卫生相关性：据估计，出生缺陷每年影响美国出生的120，000名婴儿（33人中有1人），并且是生命第一年死亡的主要病例。由于视力下降的医疗和社会影响，无眼症（无眼）、小眼症（小眼）和缺损（脉络膜裂或视神经裂无法闭合）可能会给受影响的个人及其家庭造成重大负担。本申请旨在改善与这些眼睛缺陷的遗传原因有关的现有知识，从而可以改善患者咨询、管理和治疗。

DESCRIPTION (provided by applicant): Anophthalmia, or absence of the eye, is found in 1 in 5,000 to 10,000 individuals and is a devastating birth defect because of the resulting visual impairment. Anopththalmia is closely related to microphthalmia (small eyes) and coloboma (failure of the choroid fissure or the optic fissure to close). We have studied a male patient with severe microphthalmia who had a novel chromosome deletion at chromosome 18q22.1. We have implicated one of the deleted genes at 18q22.1, TXNDC10, in eye development. In situ hybridization showed that Txndc10 was expressed in the retinal neuroepithelium and lens epithelium in the developing murine eye. We re-sequenced TXNDC10 in 66 patients with anophthalmia or microphthalmia, and found c.260G>A, predicting a missense substitution, p.R39Q, in an unrelated patient with microphthalmia and retinal coloboma. We used antisense morpholinos targeted against the zebrafish Txndc10 orthologue, Zgc110025, to show that the morphant larvae had microphthalmia and coloboma. In-situ hybridization with Pax2 showed increased choroid fissure staining in morphants compared to controls, suggesting that Pax2 dysregulation was involved in the coloboma formation. The morphant retinas had increased anti-histone H3 staining in the peripheral retina and we observed fewer late-differentiating cell types in the morphant retinas. Co-injection of human wild type TXNDC10 mRNA with a morpholino rescued the morphant phenotype, whereas co-injection of human TXNDC10/(p.R39Q) mutant mRNA with morpholino did not. Our results suggest that haploinsufficiency for TXNDC10 perturbs eye development. We propose to continue our research on TXNDC10 in two directions. We hypothesize that Txndc10 may be part of a known pathway for ventral retinal development, and would like to use zebrafish to determine whether Zgc110025 interacts with other known genes that are involved in choroid fissure closure and the formation of the ventral retina, such as Vax1, Vax2 and Shh (Syu). We will use in-situ hybridization, dual injections of antisense morpholinos and mRNA rescue experiments to accomplish this aim. Our purpose is to try to uncover the mechanism whereby Txndc10 affects eye development. Secondly, we propose to make a mouse model of loss of Txndc10 function to examine the eye phenotype in a genetic null model rather than in an animal model with only partial loss of gene function. We hypothesize that loss of Txndc10 function will produce mice with microphthalmia and coloboma, and we will use the resultant knock-out mice to examine eye morphology in a Txndc10 null animal and to perform expression arrays to evaluate for differences in gene expression between Txndc10 null mice and wildtype litter mates. Our ultimate goal is to improve the existing knowledge about the genes that are required for ventral retina formation and choroid fissure closure so that human patients with anophthalmia and related eye defects can be offered improved genetic counseling and testing. PUBLIC HEALTH RELEVANCE: Birth defects affect an estimated 120,000 (1 in 33) babies born in the United States each year, and are the leading case of mortality in the first year of life. Anophthalmia (absent eye), microphthalmia (small eye) and coloboma (failure of the choroid fissure or the optic fissure to close) can result in a significant burden for affected individuals and their families because of the medical and social effects of reduced vision. This application seeks to improve the existing knowledge pertaining to the genetic causes of these eye defects so that patient counseling, management and treatment can be improved.