Cytogenomic characterization of karyotypes with additional autosomal material

Area of Science:

• Genetics
• Genomics
• Cytogenetics

Background:

• Chromosomal rearrangements with additional material frequently lead to partial trisomy and partial monosomy.
• Understanding these rearrangements is crucial for diagnosing phenotypic alterations.

Purpose of the Study:

• To characterize chromosomal rearrangements and analyze genomic features at breakpoint regions in 31 patients with additional autosomal material.
• To investigate the origin and characteristics of these complex genomic alterations.

Main Methods:

• Utilized karyotyping, chromosomal microarray analysis (CMA), and fluorescent in situ hybridization (FISH) for patient characterization.
• Performed in silico analyses to evaluate chromosomal compartments, segmental duplications, and repetitive elements at breakpoints.

Main Results:

• Identified 47 copy number variations (CNVs) and various structural aberrations, including derivative chromosomes and tandem duplications.
• Found deletions associated with duplications in 16 of 19 patients with derivative chromosomes.
• Determined that 54.5% of rearrangements were de novo, 31.9% maternal, and 13.6% paternal in origin.

Conclusions:

• Deletions accompanying additional genetic material were present in 51.6% of patients, revealing underlying genetic imbalances.
• A positive correlation exists between chromosome size and CNV occurrence in rearrangements.
• No specific preference was observed for breakpoints in A/B compartments, repetitive elements, or segmental duplications.