Are there other related social interaction disorders that are not quite as severe as even mild Asperger's?

After years of asking my son's teachers if they thought my son's lack of having a close friend was normal, I just had a conference with his 7th grade teacher who initiated the topic.  His academic skills are progressing fine, she said, but I'm worried about his lack of social skills.  She said, and I have observed similarly, he isolates himself.  Even when instructed to work in small groups, he goes to the "edge" of the group.  When he finally interacts, she said, it's usually in a negative way such as telling on someone, trying to make himself look better or ridiculing them.  He rarely talks with kids his age, instead preferring to boss younger kids.  He never has had one solid best friend in his life.  He prefers to be in a room with few kids and seems to get anxious in a big crowd.  He clings to adults and tends to hover around the teachers and eavesdrop, according to his teacher.  Yes, there is a bit of avoiding eye contact and monotone voice but he does not act out or speak loud in inappropriate settings. He is obsessed with WWII and a particular War Hammer game and he enjoys routine but not religiously.  (Like, he doesn't need to always eat a slice of bread before salad)  He can carry on many other conversations with me about things other than those 2 subjects.   I was almost relieved to hear about Asperger's from a friend, and while he kinds fits some of the descriptions, there are other symptoms like clumsiness that he doesn't qualify for at all.  It's not something that seems to bother him.  He says he is happy and likes his school, but I am concerned. His dad, he and I are very close.    

[Rachel Thompson, Ph.D., BCBA]

Clumsiness is not among the diagnostic criteria for Asperger's Disorder. A diagnoses is made on the basis of social deficits and restricted/repetive behavior patterns. There are many children who do not meet the criteria for an Asperger's Disorder who do display some characterisitcs of this Disorder. Certainly, among developmentally typical individuals there are some folks who are more socially skilled than others. I am glad to hear that you have scheduled an appointment with a phsysician. I recommend that you share your concerns regarding you son's development with his doctor and with his school. Whether or not a diagnosis is assigned, it will be important to work on your son's social skills. Your school and pediatrician should be able to recommend some strategies or resources for social skills development.

[Sally44]

autism, including aspergers is on a spectrum.  So at one end you have typical 'normal' children and at the other you might have severely autistic children.  Somewhere within that range will be those with autism, autistic spectrum disorders, aspergers, traits of autism or aspergers etc.  It is quite possible to have traits, but not enough of them to get a diagnosis.  Also, as the diagnosis relies on having enough of the behaviours to get a diagnosis there are some children who are too able in one area to get a diagnosis.  
For example my son is diagnosed as being High Functioning Autistic.  He doesn't have any rigid routines or rituals and he doesn't have any obsessions.  If he does develop obsessions or restricted areas of interest then his diagnosis may change to Aspergers.  So it is a much more fluid thing rather than a concrete yes/no.
I think you need to raise your concerns and have your son assessed because even if he doesn't receive a diagnosis of aspergers it sounds like he may need some help with social skills.