Hello!
Yes, these are all common health problems observed in kids with autism. My son has also had severe constipation that started when he was just 20 days old. We eventually discovered that the constipation was due to cow's milk allergy, and when we took away all dairy products at 14months the constipation completely disappeared within days. Failure to thrive can be the result of celiac disease or gluten sensitivity. Both gluten and dairy are common triggers of autistic symptoms, so it may be worth trying to take your son off of these foods if you haven't already. Low carnitine and high ammonia are also frequently observed in autism. Your typical pediatrician will not be familiar with these problems, so I think your best bet would be to find a DAN! doctor (DAN! stands for Defeat Autism Now). They follow the biomedical approach to autism treatment. You can go to the TACA website (tacanow.org) to locate a good DAN! doctor in your area. A DAN! doctor will evaluate your child's individual symptoms and determine which type of treatment plan is best. My son is recovering thanks to a DAN! doctor.
Good luck!
The ammonia and constipation are completely related to Autism.The underlying cause of all these problems are vaccines.The mercury,aluminum, MMR lead to a whole bunch of problems.Their are doctors treating all the constipation/gut issues and addressing all the other biochemical imbalances and fully reversing Autism/ADD/ADHD.I myself have severe ADHD and digestive problems and I am improving with the help of these doctors.One of the doctors that talks alot about ammonia and it's relation to Autism is Amy Yasko.Her websites are holisticheal.com and holistichealth.com.Check out Rashid Buttar's video on youtube.GenerationrRescue.com is another great site with a ton of info.Good Luck.Btw the sooner you start the program the better chance you have of fully reversing Autism.
Have you had your child checked for carnitine deficiency disorders? These can cause a myriad of symptoms. We supplement our daughter with carnitor because she was failure to thrive (15 pounds at 4 years old) and she began to gain muscle mass for the first time even though some of the tests came back negative for carnitine disorders... she is also in the autism spectrum.