The Discordance between G-Banding Karyotyping and Microarray in Structural Abnormality.

Area of Science:

• Cytogenetics
• Genomics
• Molecular Diagnostics

Background:

• Cytomolecular genetic laboratory techniques have evolved significantly, from G-banding karyotyping to whole genome sequencing.
• Despite advancements in resolution, conventional and advanced techniques possess unique advantages and limitations for detecting genomic variations.

Purpose of the Study:

• To compare the chromosomal abnormalities detected by G-banding karyotyping and SNP-based microarray testing.
• To analyze the differences in detecting numerical and structural chromosomal abnormalities between the two methods.

Main Methods:

• A comparative analysis of G-banding karyotyping and SNP-based microarray testing was performed.
• Data from 62 patients, collected between July 2020 and December 2022, were analyzed for chromosomal abnormalities.

Main Results:

• Chromosomal aberrations were detected in 28 out of 62 patients by at least one method.
• Aneuploidy was detected by both methods, whereas copy number variations (gains/losses <3 Mb) and loss of heterozygosity were exclusively identified by microarray.
• G-banding karyotyping identified structural rearrangements (inversions, ring chromosomes, translocations), with microarray providing additional breakpoint information.

Conclusions:

• Significant discordance exists between G-banding karyotyping and SNP-based microarray in clinical settings.
• Understanding the complementary strengths of each technique is crucial for selecting appropriate diagnostic tools.
• Accurate detection of genomic structural variants is vital for diagnosing various diseases.