Abstract
Presentation Description :
The introduction of exome and genome sequencing in diagnostic facilities has revolutionized the medical genetics field in the past decade. Despite the broad application of these state-of-the-art technologies, still a significant number of individuals diagnosed with inherited retinal dystrophies remain genetically unexplained. Most likely this is due to “hidden” variants that are difficult to detect using short-read sequencing approaches or because of (non-coding) variants that can be identified but are challenging to interpret and have an unknown effect and pathogenicity. We use a combination of innovative approaches to circumvent these problems. Using long-read approaches, optical genome mapping and long-read genome sequencing, we have identified several examples of these hidden variants including intronic mobile element insertions and complex structural variants. To functionally assess the pathogenic consequences of these variants, (targeted) long-read RNA-sequencing is performed. We have determined that targeted long-read RNA-sequencing is a powerful and unbiased approach to detect alternative splicing defects using both blood-derived RNA or RNA isolated from iPSC-derived photoreceptor progenitor cells. Our findings suggest that non-coding variants such as mobile element insertions represent an underestimated variant class that are often overlooked, as they are difficult to detect and interpret using short-read approaches only. More focus should be put on the interpretation and classification of non-coding variants and high throughput functional validation approaches are warranted to increase diagnostic yields of inherited rare Mendelian diseases.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.