On March 11, 2025, the Prenatal Diagnosis Center at The Second Affiliated Hospital of Chongqing Medical University successfully conducted a prenatal genetic diagnosis for a fetus with complex chromosomal rearrangements (CCRs) and ventriculomegaly, using locally integrated genetic testing technology with advanced domestic platforms. This successful case not only demonstrates the hospital’s technical capabilities in diagnosing complex genetic diseases prenatally but also underscores the significant impact that new technologies can have on both families and society.
The molecular diagnostics platform at the Prenatal Diagnosis Center initiated a multi-technology joint testing approach. Using Optical Genome Mapping (OGM), a global scan identified dozens of complex breakpoints across four chromosomes. Oxford Nanopore Technologies (ONT) long-read sequencing provided a detailed analysis of the breakpoint regions, revealing an abnormal fusion between exons 1–3 of the CNOT1 gene and chromosome 21. RNA sequencing confirmed that the fusion gene caused premature termination of protein translation, thereby clarifying the pathogenic mechanism. Tracing analysis further confirmed that the abnormal chromosome originated from the father, providing critical information for genetic counseling.
Based on these test results and genetic counseling, the family was informed and decided to terminate the pregnancy. Moving forward, the hospital will continue to advance multi-platform technological innovation, promote the standardization and localization of rare disease diagnostics, and contribute further to reducing birth defects and improving public health.
