ISCN 2024: A Review of Some Additions and Changes to Constitutional Cytogenomics Nomenclature

In 2024, the latest version of the International System for Human Cytogenome Nomenclature (ISCN) was published, and it remains the current version. This version represents one of the most significant revisions of the ISCN in order to develop a more user-friendly manual. New chapters have been introduced on general ISCN rules and genomic mapping nomenclature, examples and descriptions of chromosomal abnormality and mosaicism findings have been added, and additional abbreviations have been introduced. A key aspect of ISCN 2024 is the creation of a standardized nomenclature for the consistent description of research results, regardless of the cytogenomic technology used. The review presents the most significant changes made to individual chapters regarding the general provisions of constitutional cytogenomics, classical cytogenetic research, and in situ hybridization.

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