We established the Columbia University Medical Center (CUIMC)-Weill Cornell Medical College (WCM) NNEXT site in 2011. We were refunded in 2018. Over the past four years, we have strengthened and refined our highly efficient team and infrastructure, responding to the challenges of the pandemic and a change in WCM leadership. We have been selected for all 11 trials and were the highest enrolling site in NN110 with the most underrepresented participants. Harini Sarva MD, NN10 site PI will be the new WCM mPI joining CUIMC mPIs Drs. Chiriboga and Marder. Our 6 NNEXT fellows, all assistant professors, were awarded two KL2s, several foundation grants and an R01. Relevant to new themes in gene therapy, is our experience with early phase trials assessing antisense oligonucleotides (ASOs) in spinal muscular atrophy (SMA), Huntington’s Disease (HD), Duchenne Muscular Dystrophy (DMD) and investigator-initiated n of 1 trials of ASOs in ultra-rare conditions have been developed by Columbia investigators in amyotrophic lateral sclerosis (ALS), adult polyglucosan disease and neuropediatric genetic disorders. New informatic tools for phenotyping and determining clinical trial eligibility are being developed. Our aims are 1) To continue to strengthen and integrate the network of investigators at our combined site 2) To design and conduct early phase gene therapy trials for ultra-rare diseases 3) To develop tools and best practices for recruitment and retention of racially and ethnically diverse participants a) to improve the quality of the research experience and assurance of continuity of care. b) improve dissemination of educational material to participants, families, and disease advocates about scientific advances and the importance of clinical trials 4) To fully participate in NNEXT network through generation of new study protocols, participation on steering committees, network committees, educational events, and new brainstorming sessions 5) To refine our one- year NNEXT fellowship program to train junior faculty in the design and conduct of early phase trials, especially in rare and ultra-rare diseases.