What is the recommended testing for large deletions or duplications?

The recommended testing for large deletions or duplications is karyotype analysis. Karyotype analysis is a cytogenetic technique used to visualize chromosomes under a microscope, allowing for the detection of large chromosomal abnormalities, including large deletions and duplications. This method provides a comprehensive overview of the chromosomal structure, making it particularly effective for identifying substantial rearrangements in the genome.

While other techniques, like MS-MLPA and SNP microarray, can also be used for specific types of copy number variations, they are generally more targeted and may not detect all large chromosomal alterations as effectively as karyotyping. PCR is primarily used for amplifying specific DNA sequences and is not suitable for detecting large-scale chromosomal changes. Therefore, karyotype analysis serves as the gold standard for the initial assessment of large deletions and duplications in the context of genetic counseling and diagnosis.