Which is NOT detected by chromosomal microarray?

Chromosomal microarray technology is designed to detect genomic alterations, including variations in DNA copy number. It can identify unbalanced translocations, microdeletions, and copy number variations, which represent gains or losses of genetic material.

Balanced translocations, however, do not typically result in a change in the overall amount of DNA; instead, they involve a rearrangement of the DNA sequences without any loss (deletion) or gain (duplication) of genetic material. Because balanced translocations maintain the normal copy number of genes, chromosomal microarrays are not effective in detecting them.

The focus of chromosomal microarray is on identifying discrepancies in genetic material that can lead to developmental issues or genetic syndromes, which explains its limitations in detecting balanced translocations. They are usually identified through traditional karyotyping or fluorescence in situ hybridization (FISH) techniques instead.