Genetics

TIGER enables template-independent Cas9 correction of frameshift mutations in vivo

This study describes TIGER, a Cas9-based platform that corrects frameshift mutations without an exogenous repair template. By defining nucleotide-level features that govern repair, the authors build a scoring system predicting gRNA outcomes and in-frame restoration. They report that many insertion and deletion frameshifts yield at least 30% in-frame products, often with wild-type sequence restoration. In a mouse deafness model, dual AAV delivery of SpCas9 and an optimized guide restores hearing thresholds to wild-type levels with predominantly wild-type edits. 1

Optical genome mapping plus long-read sequencing clarifies complex CNV-associated structural variants

In 30 patients with exome-detected copy-number variants, optical genome mapping was combined with targeted Nanopore long-read sequencing. This strategy uncovered additional structural variants in nearly half of cases and explained clinical features in about one-quarter via gene disruptions or copy-number changes. Even highly complex rearrangements with many segments and breakpoints were efficiently resolved, including precise breakpoint definition. The results support adding optical mapping with adaptive long-read breakpoint sequencing when CNVs are detected but their structural basis and pathogenicity remain unclear. 2

5ULTRA scores 5′UTR variants for translational impact from exome and genome data

The authors introduce 5ULTRA, a computational method to detect and prioritize 5′UTR variants that alter translation. 5ULTRA identifies SNVs, indels, and splice variants that create or disrupt uORF start or stop codons or modify Kozak strength. A machine-learning score correlates strongly with experimentally measured protein-level effects of 5′UTR variants. Application across datasets highlights candidate variants in cancer, complex traits, and rare disease, including RPSA-associated congenital asplenia and a TNF variant potentially predisposing to tuberculosis. 3