See also:
Sleep Deprivation
Illness
Dehydration
Hunger
Heat
Cold
Specialized Edition: Fire
Specialized Edition: Phobias
Specialized Edition: Mental Illness
Specialized Edition: Disabilities

Do you have or know someone who has a developmental delay or disorder, whether mental or physical? If so, would you mind helping us fellow authors better portray them in our stories?

My little brother has Down syndrome. He's nine years old (wow, time flies); ten years younger than me.
When he smiles, it's like the whole room instantly lights up. He can melt anyone's heart; he's absolutely adorable. Very huggy and loving, too, and not shy at all.

He tries to talk, but his speech comes out garbled. The doctors thought it might be because of fluid in his ears muffling sound he heard and therefore making sounds harder to reproduce correctly, so he now has tubes in his ears. They help a little, but he's not good with putting words together and enunciating them correctly. Mostly it's just one-word questions or answers (a lot of "No!" ). His fine motor functions are slow to develop (meaning he can't write legibly at this point), and his eyes have trouble focusing (they cross a lot). He's had one or two surgeries on his eyes but they didn't help much, and he refuses to wear his glasses.

His mind probably won't ever develop beyond that of a five or ten-year-old. He won't be able to live on his own or drive a car, and he'll probably never have a "real" job.

Down syndrome (or Down's syndrome, as named after John Langdon Down, the British physician who described the syndrome in 1866) *is a chromosomal condition caused by the presence of all or part of a third copy of chromosome 21. Down syndrome is the most common chromosome abnormality in humans. It is typically associated with a delay in cognitive ability (mental retardation, or MR) and physical growth, and a particular set of facial characteristics. The average IQ of young adults with Down syndrome is around 50, compared to children without the condition with an IQ of 100. (MR has historically been defined as an IQ below 70.) A large proportion of individuals with Down syndrome have a severe degree of intellectual disability.*
It's characterized by a certain set of facial features (almond-shaped eyes being the most recognizable).
There are different types and degrees of Down syndrome. Every case is unique and special.

*information between asterisks above copied from http://en.wikipedia.org/wiki/Down_syndrome *

Yes, autism is another disorder that has a very broad spectrum. I've known some people who had autism, and I couldn't even tell. But I've also been a babysitter and/or nanny for some kids who had a severe case.

Just a little bit of info:
Autism, in my experience and study, is practically the opposite of Down's syndrome. Individuals with Down's syndrome are very outgoing, happy, and even extroverted, but mentally they're "retarded," as some say; I don't use that word except in the strictly scientific sense.
Anyway, it's not hard to pull them out of their shell. They're focused, a lot of the time, on things going on around them.

Now people with autism (again, this is in my experience and study; I don't want to offend anyone; if I'm wrong, let me know) retreat into themselves and block out the world around them. This obviously isn't good. They need stimulation, people talking to them, toys that they have to make work with their hands rather than electronic ones that move by themselves. They need to be drawn out of their shell, though I'm sure it's uncomfortable and perhaps frightening for them.
Many autistic people have an amazing intellect. They just have a hard time showing it; they need patience and kindness to help them live up to their potential.

Many autistic individuals have certain somethings that they're infatuated with. For one person I knew, it was anime. For another, it was cars.

Many also have certain things they "need" to do or to have a certain way. Some have to step on every crack of the sidewalk with their right foot; some can't stand certain noises.

As an example of the low end of the spectrum, one girl I knew was pretty much completely independent. She had her driver's license and went places alone and everything. It pretty much shocked me when she finally told me she had autism.

An example of someone on the higher end would be a boy I used to help out with in church. It was like he wasn't even there - you'd talk to him, and he wouldn't even respond. He was very active and did not like to sit still, ever, and of course you couldn't tell him to sit down or calm down because he was so withdrawn mentally that he practically couldn't even hear you. He was really sweet; he just needed a lot of patience, gentleness, and attention.

Does anyone else have more information on Down's syndrome or autism?