In the context of intricate cases with ambiguous prenatal genetic diagnoses, this project intends to carry out long - read DNA sequencing data analysis on birth defect cases and family samples. The emphasis lies on the extraction and identification of individual - specific genomic characteristics, as well as the development of detection algorithms for all categories of structural variations (SV), including complex SV. It will establish a pan - genomic reference map specific to the Chinese population to facilitate the identification of pathogenic SV in birth defect cases and family samples of the Chinese population, and delineate the detailed SV spectrum of major birth defects in the Chinese population. Additionally, the project will conduct in - depth analyses of the genetic and pathogenic roles of different types of SV in birth defects, offering a theoretical foundation for promoting the early warning, intervention, and prevention of major birth defects in China.