I am not an expert, and this observation may may be premature, but your son's behavior sounds like autism to me. Here is a description of Asperger's Syndrome (sometimes spelled Ausberger's syndrome), a high functioning form of autism:
Asperger Syndrome or (Asperger's Disorder) is a neurobiological disorder named for a Viennese physician, Hans Asperger, who in 1944 published a paper which described a pattern of behaviors in several young boys who had normal intelligence and language development, but who also exhibited autistic-like behaviors and marked deficiencies in social and communication skills. In spite of the publication of his paper in the 1940's, it wasn't until 1994 that Asperger Syndrome was added to the DSM IV and only in the past few years has AS been recognized by professionals and parents.
Individuals with AS can exhibit a variety of characteristics and the disorder can range from mild to severe. Persons with AS show marked deficiencies in social skills, have difficulties with transitions or changes and prefer sameness. They often have obsessive routines and may be preoccupied with a particular subject of interest. They have a great deal of difficulty reading nonverbal cues (body language) and very often the individual with AS has difficulty determining proper body space. Often overly sensitive to sounds, tastes, smells, and sights, the person with AS may prefer soft clothing, certain foods, and be bothered by sounds or lights no one else seems to hear or see. It's important to remember that the person with AS perceives the world very differently. Therefore, many behaviors that seem odd or unusual are due to those neurological differences and not the result of intentional rudeness or bad behavior, and most certainly not the result of "improper parenting".
By definition, those with AS have a normal IQ and many individuals (although not all), exhibit exceptional skill or talent in a specific area. Because of their high degree of functionality and their naiveté, those with AS are often viewed as eccentric or odd and can easily become victims of teasing and bullying. While language development seems, on the surface, normal, individuals with AS often have deficits in pragmatics and prosody. Vocabularies may be extraordinarily rich and some children sound like "little professors." However, persons with AS can be extremely literal and have difficulty using language in a social context.
Here is a link to a fascinating blog written by the mother of a child with this syndrome:
http://adamsautism.blogspot.com/