he International System for Human Cytogenomic Nomenclature (ISCN) provides a standard approach to describe any genomic rearrangement identified by techniques ranging from karyotyping to FISH, microarray, genomic mapping, various region-specific assays, and DNA sequencing. ISCN 2024 is an indispensable reference volume for human cytogeneticists, molecular geneticists, clinical geneticists, technicians, and students for the interpretation and communication of human cytogenomic nomenclature.

Apart from making regular corrections and updates, those more fundamental changes were implemented:

• A new nomenclature is introduced specifically for genomic mapping in the diagnostic setting taking elements of karyotyping, microarray and region-specific nomenclature to describe the observed structural and copy-number variation.
• An introductory chapter summarizes the generic rules that are applicable across all techniques.
• Additional nomenclature examples have been added to most chapters and now include ISCN for chimeras, moles and chromoanasynthesis.
• The RSA chapter has been expanded to include nomenclature for targeted chromosome analysis, targeted microarray analysis, fusion genes, expansion repeats and methylation assays for imprinting.
• The ISCN examples are numbered for ease of reference.
• Finally, the Committee identified the need to streamline the nomenclature so it is consistent across the different technologies.