Autism????

How "normal" can a teen seem and still have some kind of autism?

Are there any symptoms that MUST be there for a diagnosis or does it all vary? Is there any chance someone wouldn't be diagnosed until that late anyway?

Yes, Asperger's Syndrome could very readily (depending on the person involved) be overlooked in a teenager, or even a grown adult. Speaking as an adult diagnosed at the age of 31 with Asperger's Syndrome (unexpectedly) another reason why it might not have been recognized earlier is that Asperger's Syndrome does not include the late development of speech as part of the criteria.

The DSM IV criteria lists several sets of criteria, of which it's like a "choose at least this many of this group" scenario for each one, so yes, it does vary, and autistics are like snowflakes (no, they don't melt in your uncovered hand!) and no two are perfect matches.

Asperger's Syndrome was only really recognized in the US/english-speaking world as of 1994 when it was put in the DSM IV, but it was named after the German doctor that first documented it (look that up on wikipedia).

Yacasham (I hope I got that correct) is talking about someone she knows that happens to have sensory integration issues, which is very typical. If you were as sensitive to noise, light, etc. you too, would do your best to avoid it, as it causes pain for many if they're overly sensitive to it, and can lead to sensory overload, and if they're insensitive to a given form of stimuli, they'll seek it out; this varies from person to person, and can't be assumed to be the same.

I've provided a link to a site created by those on the spectrum for you to get more insight straight from the horse's mouth, so to speak.

It would have to very mild for it not to be noticeable until now.

my cusin has autisim. he has one of the worst cases. yes, some people may call him slow or special, but he is no different. the only real problem he has is when he goes into public. he covers his ears and trys to hide. if you just have a mild version its barely noticable. but if you have a severe case, you can get medication to help. symptoms will vary. it is possible. usually people notice something right away. my cousin was 7 when he found out he had it. he was acting wierd, so he got checked. but if you notice something strange that you cant correct, get it checked because if you do have autisim, it can get worse. Hope your ok!

It would be very easy to miss a diagnosis of Asperger's Syndrome or High Functioning Autism, especially if the teen is in an environment where he is allowed or encouraged to be "geeky," like hyper-focusing on certain subjects, or his quirks are accepted as "normal," A child may be described as a picky eater, or have a preference for spending time alone. Our biggest problems with my son's autism come from being around people who don't accept his differences.
The criteria for an Autism Spectrum Disorder (ASD) fall into 3 categories: Sensory Integration, Social Interaction, and Communication

Sensory Integration differences include aversion to or cravings for certain textures, tastes, smells, a preference for darkend rooms, or bright rooms lit by only incadescent bulbs or natural light-almost universally, flourescent bulbs irritate people with autism, they can both see the flickering and hear the buzzing the bulbs make. A person with autism may rock back & forth incessantly, or hate to swing. They may hate any type of tight clothing or elastic bands or prefer wearing tight knits. They may need white noises to help concentrate or need perfect silence.

Social Interaction problems may manifest themselves as a preference for being alone, making too much or too little eye contact, needing more "space" than most people or ignoring personal boundaries. As a teen, he may be too clingy to a girlfriend or not be able to get one at all.

Communication differences that are more subtle is difficulty with abstract language & understanding hints. The person with autism may dominate a conversation, or may be reluctant to speak at all.