The National Institutes of Health (NIH) is offering a funding opportunity for in-depth phenotyping and research using knockout mouse strains that exhibit embryonic or perinatal lethality or subviability, under the R01 Clinical Trial Not Allowed grant mechanism. This initiative aims to encourage applications that leverage the International Mouse Phenotyping Consortium (IMPC) resources to better understand genetic functions related to congenital diseases and structural defects, particularly those affecting embryonic development and fertility. The program is part of a broader effort to catalog mammalian gene function, with an award ceiling of $499,999 per year for projects lasting up to five years. Interested applicants must submit their proposals by January 7, 2026, and can find additional information and guidelines at the NIH grants website or contact NIH Grants Information at grantsinfo@nih.gov.