Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal infections. It's difficult to explain but strep can have effects on the brain which can affect behaviors, etc... My son had several serious strep infections as a child and to this day has to be checked routinely for strep antibodies and also takes a maintenance dose of antibiotics to control it.

Ours is Mario and Luigi and for the other son it's Guinea Pigs. I'm hoping in the future it will be a topic that can help me....like teaching me to read a map, another language, trivia so I can win Jeopardy.

Oh, so familiar! My son has been fixated on trains (particularly Thomas), Phineus and Ferb and now Harry Potter. He is almost 8. He will go on and on and on and on and on about whatever it is right then. At school, at home, everywhere. He also loves angry birds. He really likes playing the video games over and over to hear the music so he can play it on the piano. He can play every song from tetris, Harry Potter, Angry Birds - all the versions, Phineus and Ferb and so on.

Unfortunately it is extremely common. Its almost like they have to keep doing it until they feel they know every minute detail of whatever "it" happens to be. I think it is what makes ASD kids so smart. My son is ten and he's always been that way. And really, at the end of the day, I wouldn't want him any other way. I do however agree.....its annoying!

that is very very common!! a work we have used is to have him write his facts down in a little notebook (works on handwriting but shhh dont tell) and then when he changes topics they can be little fact books for cousins, friends etc.