MG-124 The investicate project: Identification of new variation, establishment of stem cells, and tissue collection advancing treatment efforts

Abstract

Objective Neurodevelopmental disorders (NDDs) are a large and complex group of disorders with varied etiologies. Recent advances in sequencing, induced stem cells, and small molecule screening technologies provide an opportunity to develop personalised treatment for NDDs. Methods The INVESTICATE project recruits patients with NDDs from Children’s Hospitals in Canada and internationally. Patients are enrolled if they have a similarly affected sibling and negative genetic tests, or a de novo balanced chromosomal rearrangement (BCR). We use Next-Generation Sequencing tools to find variation and structural variant breakpoints. Fibroblasts from patients undergo rapid induced pluripotent stem cell (iPSC) re-programming, neural progenitor cell (NPC) differentiation, CRSIPR/Cas9 mutation correction, and finally cell phenotyping. Where feasible, we collect brains from cases with reduced life expectancy. Patient-derived NPCs undergo high-throughput small molecule screening to reverse cell phenotypes associated with disease. Results INVESTICATE has recruited six families, and we identified mutations in genes not previously associated with NDDs. We identified a stop codon altering single base deletion in one family, a 51-basepair promoter deletion in another family, and a gene truncating chromosomal translocation implicating chromatin remodelling, netrins, and maintenance of brain pH in NDDs. Functional assays using iPSC-NPCs of these rare variants support their role in disease. Conclusions INVESTICATE is a rapid bedside-to-bench and back again pipeline capable of finding variants missed using standard methodology, and complements variant detection with a full battery of cell phenotyping assays, brain collection, and high-throughput screening. INVESTICATE is well positioned to attempt to provide cost-effective, personalised care to children with NDDss.