The Ultra-Rare Gene-Based Therapy (URGenT) network supports Investigational New Drug (IND)-enabling studies and planning activities for First-in-Human (FIH) clinical testing of gene-based or transcript-directed therapeutics, such as oligonucleotides and viral-based gene therapies, for ultra-rare neurological or neuromuscular disorders. The goal of this funding opportunity announcement (FOA) is to accelerate the development of a promising clinical candidate with robust biological rationale and demonstrated proof of concept (POC) data for the intended approach in a model system relevant to a specified patient population towards an IND filing and the initiation of a clinical trial.