[Application of Bionano-DNA Full-Length Optical Mapping Technology in Genetic Diagnosis of Hemophilia A Carriers].

OBJECTIVE: To apply Bionano Saphyr visual full-length DNA optical mapping technology to the precise genetic diagnosis of hemophilia A carriers. METHODS: For 2 suspected F8 gene deficiency female carriers who could not be diagnosed by conventional next-generation sequencing technology, the full-length DNA optical mapping technology was used to detect and scan the sample X chromosome full-length visual haplotype characteristic map, which was compared with the normal haplotype. The gene structure variation information of the samples was obtained by compare with DNA atlas library. RESULTS: The average fluorescent marker length of the X chromosome DNA molecular where the F8 gene was located in the two samples was greater than 2.5 Mbp, and the average copy number was greater than 20×. After comparative analysis, one of the samples was a proximal inversion of intron 22 of the F8 gene, and another was an inversion of intron 22 accompanied by multiple deletions of large fragments. CONCLUSIONS: Bionano technology has a good detection rate for gene defects with large length and complex variation. In the absence of a proband or accurate genetic diagnosis results of the proband, the application of this technology to detect the heterozygous complex variant of the F8 gene is of great significance for the prenatal diagnosis and pre-pregnancy diagnosis of hemophilia carriers.