Human Chromosome Nomenclature: An Overview and Definition of Terms

Abstract

As the field of cytogenetics and molecular genetics evolves, a standardized nomenclature system is critical for describing karyotypes and genomic changes accurately and concisely worldwide. The International System for Human Cytogenetic Nomenclature or ISCN is the communication tool for describing human chromosomes and chromosomal aberrations associated with human disease. This reference has served cytogeneticists since 1960, and through its periodic updates, it continues to provide standardized guidelines for consistency in the descriptive and interpretive reporting of the various chromosome aberrations observed in constitutional and neoplastic disorders. This chapter describes the general principles of the ISCN and offers guidance on writing abnormal cytogenetic results by providing nomenclature examples.