Le Tien, Htun Stephanie, Pandey Manoj Kumar, Sun Yihui, Magnusen Albert Frank, Ullah Ehsan, Lauzon Julie, Beres Shannon, Lee Chung, Guan Bin, Hufnagel Robert B, Brooks Brian P, Baranzini Sergio E, Slavotinek Anne
Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.
Division of Medical Genetics, Department of Pediatrics, University of California San Francisco, San Francisco, CA, United States.
Front Cell Dev Biol. 2025 Mar 6;13:1522094. doi: 10.3389/fcell.2025.1522094. eCollection 2025.
Heterozygous deletions predicting haploinsufficiency for the Cysteine Rich Motor Neuron 1 () gene have been identified in two families with macrophthalmia, colobomatous, with microcornea (MACOM), an autosomal dominant trait. encodes a type I transmembrane protein that is expressed at the cell membrane of lens epithelial and fiber cells at the stage of lens pit formation. Decreased Crim1 expression in the mouse reduced the number of lens epithelial cells and caused defective adhesion between lens epithelial cells and between the epithelial and fiber cells.
We present three patients with heterozygous deletions and truncating variants predicted to result in haploinsufficiency for as further evidence for the role of this gene in eye defects, including retinal coloboma, optic pallor, and glaucoma. We used Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Cas9 to make a stable model of crim1 deficiency, generating zebrafish that were homozygous for a 2 basepair deletion, c.339_340delCT p.Leu112Leu*, in .
Homozygous, larvae demonstrated smaller eyes and small and misshapen lenses compared to controls, but we did not observe colobomas. Bulk RNA-Seq using dissected eyes from larvae and controls at 72 h post fertilization showed significant downregulation of crim1 and chloride intracellular channel 4 () and upregulation of fibroblast growth factor 1b () and complement component 1, q subcomponent (), amongst other dysregulated genes.
Our work strengthens the association between haploinsufficiency for and eye defects and characterizes a stable model of loss of function for future research.
在两个患有巨眼症、伴有小角膜的缺损（MACOM）的家族中，已鉴定出预测富含半胱氨酸运动神经元1（Crim1）基因单倍剂量不足的杂合缺失，MACOM是一种常染色体显性性状。Crim1编码一种I型跨膜蛋白，在晶状体窝形成阶段在晶状体上皮细胞和纤维细胞的细胞膜上表达。小鼠中Crim1表达降低会减少晶状体上皮细胞数量，并导致晶状体上皮细胞之间以及上皮细胞与纤维细胞之间的粘附缺陷。
我们报告了三名患有杂合缺失和截短变异的患者，这些变异预计会导致Crim1单倍剂量不足，以此作为该基因在眼部缺陷（包括视网膜缺损、视神经苍白和青光眼）中作用的进一步证据。我们使用成簇规律间隔短回文重复序列（CRISPR）/Cas9构建了一个稳定的crim1缺陷斑马鱼模型，产生了在Crim1基因中存在2个碱基对缺失（c.339_340delCT p.Leu112Leu*）的纯合斑马鱼。
与对照相比，纯合的crim1−/−幼虫眼睛较小，晶状体小且形状异常，但我们未观察到缺损。在受精后72小时，使用来自crim1−/−幼虫和对照的解剖眼睛进行的批量RNA测序显示，crim1和氯离子细胞内通道4（Clcn4）显著下调，成纤维细胞生长因子1b（Fgf1b）和补体成分1q亚成分（C1q）上调，以及其他一些基因表达失调。
我们的工作加强了Crim1单倍剂量不足与眼部缺陷之间的关联，并为未来研究表征了一个稳定的Crim1功能丧失模型。
