As with any disability there are challenges but most people with Larsen Syndrome lead full lives. Whether someone achieves "true happiness" depends on so many other factors than Larsen Syndrome so I think this is a ridiculous question.
Of course you can be happy! This disease is degenerative, does not shorten life expectancy and, if you have family support and an appropriate social environment full of personal relationships healthy, you can live a life absolutely full.
We had no idea when we were pregnant that our son had LS. In fact we didn't know he had LS till he was 1 month old. Bryce was born with both hips and his right knee dislocated and clubbed feet. The first doctor we took him to thought that Bryce...