Eye Genetics Research Unit, Sydney Children's Hospitals Network, Save Sight Institute, Children's Medical Research Institute, University of Sydney, Sydney, NSW 2000, Australia.
Specialty of Genomic Medicine, Faculty of Medicine and Health, University of Sydney, Sydney, NSW 2000, Australia.
Int J Mol Sci. 2022 Mar 31;23(7):3905. doi: 10.3390/ijms23073905.
The inherited retinal dystrophies (IRDs) are a clinically and genetically complex group of disorders primarily affecting the rod and cone photoreceptors or other retinal neuronal layers, with emerging therapies heralding the need for accurate molecular diagnosis. Targeted capture and panel-based strategies examining the partial or full exome deliver molecular diagnoses in many IRD families tested. However, approximately one in three families remain unsolved and unable to obtain personalised recurrence risk or access to new clinical trials or therapy. In this study, we investigated whole genome sequencing (WGS), focused assays and functional studies to assist with unsolved IRD cases and facilitate integration of these approaches to a broad molecular diagnostic clinical service. The WGS approach identified variants not covered or underinvestigated by targeted capture panel-based clinical testing strategies in six families. This included structural variants, with notable benefit of the WGS approach in repetitive regions demonstrated by a family with a hybrid gene and hemizygous missense variant involving the opsin genes, and . There was also benefit in investigation of the repetitive GC-rich ORF15 region of . Further molecular investigations were facilitated by focused assays in these regions. Deep intronic variants were identified in and , with functional RNA based studies of the variant revealing activation of a cryptic splice acceptor site. While targeted capture panel-based methods are successful in achieving an efficient molecular diagnosis in a proportion of cases, this study highlights the additional benefit and clinical value that may be derived from WGS, focused assays and functional genomics in the highly heterogeneous IRDs.
遗传性视网膜病变（IRDs）是一组临床和遗传上复杂的疾病，主要影响视杆和视锥光感受器或其他视网膜神经元层，新兴的治疗方法预示着需要进行准确的分子诊断。靶向捕获和基于面板的策略可以检查部分或全部外显子，为许多经过测试的 IRD 家族提供分子诊断。然而，大约三分之一的家庭仍然无法解决问题，无法获得个性化的复发风险，也无法获得新的临床试验或治疗。在这项研究中，我们研究了全基因组测序（WGS）、靶向捕获和功能研究，以协助解决未解决的 IRD 病例，并促进这些方法整合到广泛的分子诊断临床服务中。WGS 方法在六个家庭中发现了靶向捕获面板临床检测策略未涵盖或研究不足的变体，包括结构变体，WGS 方法在重复区域的优势明显，这在一个涉及视蛋白基因的杂种基因和半合子错义变体的家庭中得到了证明， 和 。在 中重复的 GC 丰富的 ORF15 区域的调查中也有好处。在这些区域进行了靶向捕获面板方法的进一步分子研究。在 和 中鉴定出了深内含子变体， 变体的功能性 RNA 研究揭示了一个隐蔽的剪接受体位点的激活。虽然靶向捕获面板方法在一定比例的病例中成功地实现了高效的分子诊断，但这项研究强调了 WGS、靶向捕获和功能基因组学在高度异质性的 IRDs 中可能带来的额外益处和临床价值。
