Does Klinefelter Syndrome Cause Abnormalities?

It is sustainable because of checkpoints in a cell's cycle and it has helped with evolution; but in some cases it has, caused abnormalities when replicating that are not good. An example of where it has helped with humans is some have a denser bone structure and the ability to see underwater with a clearer vision that has helped them to survive in their environment, but klinefelter syndrome would be an abnormality that has helped no one.