Microduplication
The gain of a tiny piece of a chromosome, a piece so small its presence is not apparent on ordinary examination (using a regular light microscope to look at chromosomes prepared in the usual fashion).
The detection of microduplications requires special techniques such as high-resolution chromosome banding, molecular chromosome analysis (with FISH), or molecular genetic analysis.
Disorders caused by microduplications include Charcot-Marie-Tooth disease type 1A (CMT1A) and the microduplication 22q11.2 syndrome.
The prefix 'micro-' is derived from the Greek 'mikros' meaning small.
It diminishes whatever it precedes.