genetic testing

my sons ages 4 and 2 1/2 were diagnosed with autism.. my 4 year old about 2 years ago and my 2 1/2 year old about 6 months ago.. As i read more about autism and genetic disease that mimick autism I believe that my youngest actually sounds like he has fragile x more then autism..I am wondering if the amino i had when i was pregnant would have picked up fragile x..also i question whether my oldest may have down syndrome or some form of mental retardation to a point because of his facial features..should i put my foot down and ask for genetic screening work up done on both of them. there old doctor was thinking about it and he has since left the practice so now they have a new doctor..but she really doesn't seemed concerned about them at all.. even questions whether they should have been diagnosed with autism , which is odd because i am positive my oldest has autism but wasn't sure if he can have autism and a genetic disorder also..please help

[Lisa Kessler, MS, CGC]

It sounds like you have so much happening with your family.  I hope that this helps to answer your questions.  As you know, autism is a complex behavioral disorder which affects social interaction, communication, and causes repetitive behaviors.  Yes, it is possible to have a genetic condition and also have autism.  Autism can run in families, and about 10% of individuals with autism have an identified chromosomal or genetic problem.  

In your question, you mentioned Fragile X syndrome.  This is a genetic condition that causes cognitive disabilities and often includes autism spectrum disorders.  Given the history of autism in both of your sons, it sounds as if they would benefit from a genetics evaluation with a pediatric clinical geneticist.  A clinical geneticist will perform a detailed physical exam, and may order tests to help determine if there is a genetic cause for the symptoms that your children have.  You can find a geneticist through the American College of Medical Genetics.  Best wishes to you and your family.