I am not a psychologist nor psychiatrist. That being said, I can try to provide my take:
Atypical means NOT typical. So he may exhibit SOME symptoms of autism but not all. The catgegory PDD-nos (not otherwise specified) this is a catch-all diagnosis when some symptoms are there but not EXACTLY as indicated in the diagnostic criteria.
I'm quoting the DSM -IV here:
299.80 Pervasive Developmental Disorder Not Otherwise Specified (Including Atypical Autism)
This category should be used when there is a severe and pervasive impairment in the development of reciprocal social interaction or verbal and nonverbal communication skills, or when stereotyped behavior, interests, and activities are present, but the criteria are not met for a specific Pervasive Developmental Disorder, Schizophrenia, Schizotypal Personality Disorder, or Avoidant Personality Disorder. For example, this category includes atypical autism --- presentations that do not meet the criteria for Autistic Disorder because of late age of onset, atypical symptomatology, or subthreshold symptomatology, or all of these.
I think DSM-IV TR is the most recent version. The DSM (Diagnostic and Statistical Manual) is what psychiatrists use to diagnose conditions and disorders. . It is published by the American Psychiatric Association. Autistic spectrum and PDD disorders are around codes 299.00 to 299.80.
You may want to sugest to your consultant to update his/her information. Maybe this diagnosis may give you insurance problems later. I'm not sure but that the diagnosis atypical autism my not be currently recognized by the American Psychiaatric Association. You could ask what version of the DSM was used and and show you the classification criteria. It seems to me PDD-nos (299.80) is perhaps the a more accurate description and coding.
Here are the versions up to the DSM-IV:
DSM Versions I–IV, 1952–2000
Copyright 1994-2018MedHelp.All rights reserved. MedHelp is a division of Vitals Consumer Services, LLC.
The Content on this Site is presented in a summary fashion, and is intended to be used for educational and entertainment purposes only. It is not intended to be and should not be interpreted as medical advice or a diagnosis of any health or fitness problem, condition or disease; or a recommendation for a specific test, doctor, care provider, procedure, treatment plan, product, or course of action. MedHelp is not a medical or healthcare provider and your use of this Site does not create a doctor / patient relationship. We disclaim all responsibility for the professional qualifications and licensing of, and services provided by, any physician or other health providers posting on or otherwise referred to on this Site and/or any Third Party Site. Never disregard the medical advice of your physician or health professional, or delay in seeking such advice, because of something you read on this Site. We offer this Site AS IS and without any warranties. By using this Site you agree to the following Terms and Conditions. If you think you may have a medical emergency, call your physician or 911 immediately.