In which genetic condition, each cell in the affected person has three sex chromosomes $\text{XXY}$?

Klinefelter's Syndrome is a genetic disorder caused by the presence of an additional copy of X-chromosome resulting in a karyotype of $47,\text{XXY}$. Such individuals are sterile males with some feminine features (like Gynaecomastia). Turner's Syndrome is $45,\text{XO}$.