Davydenko Kseniya, Filatova Alexandra, Skoblov Mikhail
Department of Functional Genomics, Research Centre for Medical Genetics, Moscow, Russia.
J Cell Mol Med. 2025 Mar;29(6):e70459. doi: 10.1111/jcmm.70459.
Haploinsufficiency of the PAX6 gene causes aniridia, a congenital eye disorder characterised by the absence or malformation of the iris and foveal hypoplasia. Previous studies indicate that pathogenic splice variants account for up to 15% of all disease-causing PAX6 variants. However, this proportion may be significantly underestimated because the pathogenicity of splice variants can only be accurately established through experimental validation. In this study, we developed and validated a system of eight minigene constructions for the functional analysis of splicing variants in the PAX6 gene. This system covers all PAX6 coding exons and allows the analysis of any exon and most intronic variants of PAX6. Our comprehensive approach, employing fragment analysis and deep targeted sequencing, enabled us to accurately characterise 38 previously described PAX6 variants, including challenging cases with multiple splicing events. The application of our system revealed that the number of pathogenic splicing variants might be closer to 30% of all pathogenic PAX6 variants. This finding considerably reshapes our understanding of their significance in the genetic landscape of aniridia.
PAX6基因单倍剂量不足会导致无虹膜症，这是一种先天性眼部疾病，其特征为虹膜缺失或畸形以及黄斑发育不全。先前的研究表明，致病性剪接变异体占所有致病PAX6变异体的比例高达15%。然而，这一比例可能被严重低估，因为剪接变异体的致病性只能通过实验验证才能准确确定。在本研究中，我们开发并验证了一个由八个小基因构建体组成的系统，用于对PAX6基因的剪接变异体进行功能分析。该系统涵盖了所有PAX6编码外显子，并允许对PAX6的任何外显子和大多数内含子变异体进行分析。我们采用片段分析和深度靶向测序的综合方法，能够准确鉴定38个先前描述的PAX6变异体，包括具有多个剪接事件的复杂病例。我们系统的应用表明，致病性剪接变异体的数量可能接近所有致病性PAX6变异体的30%。这一发现极大地重塑了我们对它们在无虹膜症遗传格局中重要性的理解。
