Not really sure if there is any set age to them loosing their teeth but i seem to remember hearing if they get their milk teeth late they'll generally loose them a bit later than average. I think i read on a website once that some children with DS can still have all their milk teeth at about 14/15! I think the average age that kids loose their 1st teeth is about 5 or 6.
Brodie lost his first tooth just before his 6th Birthday and lost his top two a couple of weeks ago. So far there's nothing growing back at the top but he has two of his adult teeth coming through at the bottom even though one of them isn't even out yet! lol My main concern now is that his adult teeth aren't going to last very long cause he grinds them all the time!