Highlights Assessment of clinically significant copy number alterations (CNAs) and copy-neutral loss-of-heterozygosity (CN-LOH) in myeloid malignancies by chromosomal microarray (CMA) can improve diagnostic yield, refine risk-stratification and provide genomic information to guide therapy. The Cancer Genomics Consortium (CGC) Working Group for Myeloid Neoplasms performed an extensive systematic examination of the peerreviewed literature to evaluate the clinical value of CMA testing in the workup of myelodysplastic syndrome (MDS), myelodysplastic/myeloproliferative neoplasms (MDS/MPN) and myeloproliferative neoplasms (MPN). Based on the evidence, this review describes the specific clinical scenarios where CMA can complement the information obtained by current standard-of-care testing modalities. An example of a testing algorithm illustrating how CMA can be incorporated in selected settings within the backbone of the current testing guidelines is provided. In addition, the current review provides an exhaustive list of recurrent CNAs and CN-LOH observed in these myeloid neoplasms and their clinical significance.

Genetic testing is beneficial for patients and providers when in search of answers to medical problems related to the prenatal or early postnatal period. It can help to identify the cause or confirm a diagnosis associated with developmental delay, intellectual disability, dysmorphic features, heart defects, multiple malformations, short stature, stillbirth, neonatal death, or fertility problems. Genetic testing can be used to rule out single‐gene or chromosome abnormalities. Different diagnostic cytogenetic and molecular genetic techniques are applied in clinical genetics laboratories, from conventional ones to the state of the art chromosomal microarrays and next‐generation sequencing. Each of the genetic techniques or methods has its strengths and limitations, however different methods complement each‐other in trying to identify the genetic variation(s) responsible for a medical condition, especially the ones related to birth defects.