Abnormal development of the ocular anterior segment may lead to a spectrum of clinical phenotypes ranging from primary congenital glaucoma (PCG) to variable anterior segment dysgenesis (ASD). The main objective of this study was to identify the genetic alterations underlying recessive congenital glaucoma with ASD (CG-ASD). Next-generation DNA sequencing identified rare biallelic CPAMD8 variants in four patients with CG-ASD and in one case with PCG. CPAMD8 is a gene of unknown function and recently associated with ASD. Bioinformatic and in vitro functional evaluation of the variants using quantitative reverse transcription PCR and minigene analysis supported a loss-of-function pathogenic mechanism. Optical and electron microscopy of the trabeculectomy specimen from one of the CG-ASD cases revealed an abnormal anterior chamber angle, with altered extracellular matrix, and apoptotic trabecular meshwork cells. The CPAMD8 protein was immunodetected in adult human ocular fluids and anterior segment tissues involved in glaucoma and ASD (i.e., aqueous humor, non-pigmented ciliary epithelium, and iris muscles), as well as in periocular mesenchyme-like cells of zebrafish embryos. CRISPR/Cas9 disruption of this gene in F0 zebrafish embryos (96 hpf) resulted in varying degrees of gross developmental abnormalities, including microphthalmia, pharyngeal maldevelopment, and pericardial and periocular edemas. Optical and electron microscopy examination of these embryos showed iridocorneal angle hypoplasia (characterized by altered iris stroma cells, reduced anterior chamber, and collagen disorganized corneal stroma extracellular matrix), recapitulating some patients’ features. Our data support the notion that CPAMD8 loss-of-function underlies a spectrum of recessive CG-ASD phenotypes associated with extracellular matrix disorganization and provide new insights into the normal and disease roles of this gene.

眼前节的异常发育可能导致一系列临床表型，从原发性先天性青光眼（PCG）到可变性前节发育不全（ASD）。这项研究的主要目的是确定隐性先天性青光眼与ASD（CG-ASD）的遗传改变。下一代DNA测序在4例CG-ASD患者和1例PCG患者中鉴定出罕见的双等位基因CPAMD8变体。CPAMD8是功能未知的基因，最近与ASD相关。使用定量逆转录PCR和微基因分析的变异的生物信息学和体外功能评估支持功能丧失的致病机制。对其中一例CG-ASD病例的小梁切除术标本进行光学和电子显微镜检查，结果显示前房角异常，细胞外基质改变，并导致小梁细胞凋亡。CPAMD8蛋白在青光眼和ASD（即房水，无色素睫状上皮和虹膜肌肉）的成年人眼液和前节组织以及斑马鱼胚胎的眼周间充质样细胞中被免疫检测。F0斑马鱼胚胎（96 hpf）中该基因的CRISPR / Cas9破坏导致不同程度的总体发育异常，包括小眼症，咽部发育不良以及心包和眼周水肿。这些胚胎的光学和电子显微镜检查显示虹膜角膜角发育不全（特征在于虹膜基质细胞改变，前房减少和胶原蛋白紊乱的角膜基质细胞外基质），概括了一些患者的特征。我们的数据支持以下观点 和胶原蛋白破坏了角膜基质细胞外基质），重现了某些患者的特征。我们的数据支持以下观点 和胶原蛋白破坏了角膜基质细胞外基质），重现了某些患者的特征。我们的数据支持以下观点CPAMD8功能丧失是与细胞外基质紊乱相关的一系列隐性CG-ASD表型的基础，并为该基因的正常和疾病作用提供了新见解。