Adjective
XXY
Having an aneuploidy in the configuration of chromosomes by having an extra Y chromosome.
Postnatal overgrowth leading to childhood tall stature—includes: Klinefelter syndrome (XXY), SHOX excess syndromes, XYY. Source: Internet
Once in every 500 male births, for example, the sex chromosome complement is XXY rather than XY, thus erring in the direction of femaleness. Source: Internet
Like XXY boys and XXX girls, they are more likely to have learning difficulties. Source: Internet