Peters异常：角膜基质中角膜细胞分化及细胞外基质异常

Peters异常以角膜内皮和Descemet膜的缺陷为特征，二与角膜中央的透明性及角膜与晶状体和虹膜的前表面粘连有关。大约50％的病例有前房角发育异常，多为双眼发病。据报道，干扰视神经嵴细胞的迁移和分化有可能导致Peters异常。这种眼部异常可联合全身发育异常，可能是由于在胚胎发育过程中神经嵴细胞机能障碍所致。     

Peters异常:角膜基质中角膜细胞分化及细胞外基质异常

Peters异常以角膜内皮和Descemet膜的缺陷为特征,二者与角膜中央的透明性及角膜与晶状体和虹膜的前表面粘连有关。大约50％的病例有前房角发育异常,多为双眼发病。据报道,干扰视神经嵴细胞的迁移和分化有可能导致Peters异常。这种眼部异常可联合全身发育异常,可能是由于在胚胎发育过程中神经嵴细胞机能障碍所致。     

Axenfeld-Rieger综合征

Axenfeld异常和Rieger异常及其综合征属于一组发育性疾病的临床变异,其特征有:(1)双眼发育性缺陷;(2)常有家族史,通常为常染色体显性遗传;(3)常伴有其他发育缺陷;(4)继发性青光眼的发病率较高。部分患者之间眼部和非眼部缺陷互相重叠,使按照传统标准进行分类发生困难。进行再分类似乎很少有临床价值,因此推荐使用Axenfeld-Rieger综合征这一集合名称代表此组疾病的各种变异。眼部缺陷受累的组织似乎源自神经嵴细胞而非中胚层。根据本综合征发病机理的新理论,推测在妊娠末3个月时,源于神经嵴细胞的组织发育停滞,其结果造成房水排出结构发育不全,此与青光眼的发生有关,原始上皮层发育停滞,则与虹膜角膜条带和虹膜赤道部改变有关。后一种改变在出生后可继续发展。鉴别诊断包括虹膜角膜内皮综合征和后部多形性萎缩,另外两种疾病在临床和组织病理方面的变化和Axenfeld-Rieger综合征非常相似。然而,这三种情虽然均累及共同的原始的始基但在发病机理方面似乎具有根本的不同。本综合征患者的治疗主要包括对继发性青光眼的治疗,此种青光眼是很难于控制的,通常需行手术治疗,并且要适当安排对其他发育异常的治疗。     

Pax6基因与眼发育异常

Pax6基因是在寻找WAGR综合征致病基因时被鉴定为无虹膜症的侯选基因，在生物生长发育中起重要作用，与虹膜发育、晶状体形成后期、角膜及神经视网膜形成等密切相关。Pax6基因突变与无虹膜症以及其它一些眼先天性异常有关。本主要就Pax6基因的结构特点、与眼发育的关系以及与Pax6基因突变相关的眼发育异常作一综述。     

Pax6基因与眼发育异常

Pax6基因是在寻找WAGR综合征致病基因时被鉴定为无虹膜症的侯选基因,在生物生长发育中起重要作用,与虹膜发育、晶状体形成后期、角膜及神经视网膜形成等密切相关。Pax6基因突变与无虹膜症以及其它一些眼先天性异常有关。本文主要就Pax6基因的结构特点、与眼发育的关系以及与Pax6基因突变相关的眼发育异常作一综述。     

Rieger综合症1例

Rieger综合症是眼前部中胚层发育异常并发外胚层组织的发育不全，临床主要体征为眼，面部、牙齿及肌肉、骨胳发育异常，眼部主要表现为角膜、虹膜和前房的异常，易继发青光眼，现将我院1例报告如下。     

眼-皮肤黑变病与青光眼

眼-皮肤黑变病(oculodermal melanocytosis)是胚胎期神经嵴发育异常所致的先天性黑色素细胞沉着过度。主要沿三叉神经各分支分布。眼部常见于结膜、角膜、浅层巩膜、前房角、晶体、虹膜、脉络膜、视乳头部,也可发生于全眼球,且与葡萄膜黑色素瘤的形     

Sturge-Weber综合征的视网膜血管异常

Ｓｔｕｒｇｅ－Ｗｅｂｅｒ综合征的视网膜血管异常余杨桂李志英关键词斯特基－韦伯综合征视网膜血管发育异常病例报告Ｓｔｕｒｇｅ－Ｗｅｂｅｒ综合征又称大脑－眼－颜面血管瘤病，属斑痣性错构瘤之一种，是胚胎早期中胚叶和神经外胚层发育异常所致的脑、眼、颜面血管发育...     

先天性葡萄膜外翻

先天性葡萄膜外翻是一种罕见的眼科疾病,以虹膜基质前表面存在虹膜色素上皮、房角发育异常、进行性青光眼为特征.一般为非进行性,最主要的并发症是发展为先天性或青少年型青光眼.此病与神经嵴发育异常相关,可与某些遗传病伴发.较为特殊的临床表现是环绕瞳孔的虹膜色素膜样外翻,终止于虹膜的中周部.边界清晰,外翻的程度各方向不尽相同.几乎所有患者在确诊后都行滤过性手术治疗.     

先天性葡萄膜外翻

先天性葡萄膜外翻是一种罕见的眼科疾病,以虹膜基质前表面存在虹膜色素上皮、房角发育异常、进行性青光眼为特征.一般为非进行性,最主要的并发症是发展为先天性或青少年型青光眼.此病与神经嵴发育异常相关,可与某些遗传病伴发.较为特殊的临床表现是环绕瞳孔的虹膜色素膜样外翻,终止于虹膜的中周部.边界清晰,外翻的程度各方向不尽相同.几乎所有患者在确诊后都行滤过性手术治疗.     

Origins of avian ocular and periocular tissues

The mesenchyme which surrounds the avian embryonic eye and forms all periocular skeletal and connective tissues, including the orbit and part of the cornea, is derived from two sources, the ectodermal neural crest and the mesoderm. Due to difficulties in distinguishing cells of these separate origins, the precise contributions of each to periocular tissues has not been defined. By transplanting labeled neural creast or mesoderm cells into unlabeled host embryos we have been able to catalogue first the migratory patterns of these populations and then their precise derivatives. Some donor tissues were labeled with [³H]thymidine; in other cases embryonic quail cells, which contain a replicating heterochromatin marker, were grafted into chick hosts. As the optic vesicle forms, its caudal (future temporal) surface is contacted by a sparse population of mesodermal mesenchyme; the rest of the eye is closely surrounded by superficial ectoderm. Shortly thereafter neural crest cells migrate over the caudal and rostral surfaces of the eye, forming the maxillary and frontonasal processes as well as presumptive scleral and choroidal cells. Neural crest cells form all of the skeletal and connective tissues adjacent to the medial, fnasal, ienrior, and lateral parts of the eye, including the endothelial and stromal cells of the cornea and much of the orbit. Most of the tissues behind the eye are derived from mesoderm, with the exception of the squamosal (temporal) bone. The myofibers of extrinsic ocular muscles are mesodermal, but connective tissues associated with these muscles are of neural crest origin. The ciliary muscles are formed from neural crest cells. Periocular vascular endothelial cells are all mesodermal, but peri-vascular connective tissues, including associated smooth muscles cells, are of neural crest origin. By performing heterotopic transplantations, for example replacing the chick prosencephalic neural crest with quail metencephalic crest, we have proved that neural crest cells from other regions of the head can mimic the development of periocular crest cells. This proves that the environment through which these cells migrate plays an essential role in establishing the timing and spatial patterns of their movement. Included in the environment are the basement membranes associated with epithelial tissues, such as the optic vesicle and superficial ectoderm. We have described several instances in which basement membranes underlying these epithelia become tightly apposed and appear to act as barriers to cell migration. The patterns of basement membrane apposition and subsequent separation are described and correlated with patterns of mesenchymal cell migrations.     

Congenital ectropion uveae with glaucoma

Congenital ectropion uveae (CEU) is a rare, nonprogressive anomaly characterized by the presence of iris pigment epithelium on the anterior surface of the iris stroma, often associated with neurofibromatosis and occasionally with other ocular anomalies. We present eight patients with unilateral CEU. Seven patients had glaucoma in the involved eye, while the eighth was a 10-week-old infant. In the two patients with bilateral glaucoma, the second eye was similar to the first, but without CEU. Three patients had neurofibromatosis, two had facial hemihypertrophy, one had Rieger's anomaly, one had Prader-Willi syndrome, and one had no systemic anomalies. Two had initially been misdiagnosed as having a large pupil in the involved eye and one as having a Horner's syndrome in the uninvolved eye. The finding of CEU in an infant warrants continued observation for the development of glaucoma and disorders of neural crest origin.     

The contralateral eye in the iridocorneal endothelial (ICE) syndrome

Examination of six cases of iridocorneal endothelial (ICE) syndrome revealed that all the patients had subclinical abnormalities in the fellow eye. Of the six, four patients had iris transillumination, four patients had significantly decreased outflow facility but without elevation of intraocular pressure, and all patients had corneal endothelial changes as noted by specular microscopy. The asymmetric rather than unilateral involvement and the similar histopathology to posterior polymorphous dystrophy suggested that these two diseases may share a common pathogenesis. The occurrence of features of Rieger's syndrome and Axenfeld's anomaly in association with posterior polymorphous dystrophy suggested the hypothesis that all these diseases may be characterized by abnormalities of tissues derived from neural crest cells. A unifying hypothesis is presented to explain this group of diseases involving the endothelial cells lining the anterior chamber, namely corneal and trabecular meshwork endothelium, anterior iris stroma and iris melanophores.     

A review of anterior segment dysgeneses

The anterior segment dysgeneses are an ill-defined group of ocular developmental abnormalities that share some common features and have a high prevalence of glaucoma. Current classification of what are and what are not anterior segment dysgeneses seems to vary and our knowledge of them is incomplete. As the limits of classical clinical medicine based on evaluation of signs and symptoms are reached, further advancements increasingly will come from molecular medicine and genetics. In this article we review the normal and abnormal development of the anterior segment (concentrating primarily upon neural crest derived dysgeneses), describe the various clinical entities produced and their diagnosis, and discuss the current knowledge of the genetics of these disorders. We also suggest a new approach to the classification of anterior segment dysgeneses, based upon the embryological contribution to the formation of the anterior segment of the eye.     

Fate mapping of neural crest cells during eye development using a protein 0 promoter-driven transgenic technique

PURPOSE: To map neural crest cell fate during eye development. METHODS: Neural crest cells were tracked in developing mouse eyes using a transgene expressing Cre recombinase controlled by the Protein 0 promoter and a Rosa26 Cre-responsive reporter gene that produced beta-galactosidase after Cre-mediated recombination. RESULTS: beta-galactosidase-positive cells were detected in the periocular segment on embryonic day (E) 9.5. Several neural crest cell-derived tissues including corneal stroma, corneal endothelium, iridocorneal angle, ciliary body, primary vitreous and eyelid were strongly stained on E13.5-E18.5. The staining decreased in the corneal stroma after birth, but persisted in the presumptive iridocorneal angle. CONCLUSIONS: Protein 0-Cre transgenic mice offer a conditional knock-out strategy to investigate anterior eye segment differentiation.     

Retinal and optic nerve findings in Goldenhar-Gorlin syndrome

Involvement of the posterior segment of the eye in Goldenhar-Gorlin syndrome is more common than is generally appreciated. We examined seven patients with this syndrome. Abnormalities included diminished visual acuity, tilted optic disc, optic nerve hypoplasia, tortuous retinal vessels, macular hypoplasia and heterotopia, microphthalmia and anophthalmia. In one case, pathologic study showed agenesis of the optic nerve. It is proposed that retinal, optic nerve and craniofacial abnormalities in this condition may reflect an asynchrony in the migration of the neural crest cells in the early stages of embryonal development.