Derivative chromosome

A derivative chromosome (der) is a structurally rearranged chromosome generated either by a rearrangement involving two or more chromosomes or by multiple aberrations within a single chromosome (e.g. an inversion and a deletion of the same chromosome, or deletions in both arms of a single chromosome). The term always refers to the chromosome that has an intact centromere.

Example
Example karyotype: 46,XY,der(4)t(4;8)(p16;q14) pat This indicates a male with a derivative chromosome 4 which is the result of a translocation between the short arm of chromosome 4 at band 16 and the long arm of chromosome 8 at band 14, of paternal origin.

Reference
An International System for Human Cytogenetic Nomenclature, Shaffer, L.G., Tommerup N. (eds); S. Karger, Basel 2005