Accurate Detection of Multiple Chromosome Rearrangements and Copy Number Variations by PacBio Sequencing in Complex...

Area of Science:

• Genetics and Genomics
• Reproductive Medicine
• Bioinformatics

Background:

• Accurate detection of complex chromosomal balanced translocations (CCBTs) is essential for successful live births.
• CCBTs involving multiple chromosomes present diagnostic challenges.
• Assisted reproduction is often utilized by families with recurrent miscarriages due to CCBTs.

Purpose of the Study:

• To investigate the chromosomal characteristics of a rare family with CCBTs using advanced sequencing technology.
• To precisely locate translocation breakpoints in a complex chromosomal rearrangement.
• To evaluate the utility of PacBio sequencing in characterizing CCBTs for improved clinical detection.

Main Methods:

• Whole-genome sequencing using the PacBio platform for breakpoint identification.
• Optical Genome Mapping (OGM) and Copy Number Variation sequencing (CNV-seq) for validation.
• Bioinformatic analysis to reconstruct derivative chromosomes and assess copy number alterations.

Main Results:

• PacBio sequencing identified 12 breakpoints in a rare CCBT involving three chromosomes, revealing complex rearrangements.
• Previous karyotyping and FISH diagnoses were refined, with PacBio providing more comprehensive breakpoint information.
• OGM and CNV-seq confirmed PacBio findings; no pathogenic copy number alterations were detected.

Conclusions:

• PacBio sequencing offers high-resolution breakpoint mapping for rare and complex chromosomal balanced translocations.
• This technology enhances the precise characterization of CCBTs, potentially improving reproductive outcomes.
• The study highlights the clinical utility of PacBio in diagnosing complex genetic rearrangements.