Fact sheet on dysgraphia and comorbid disorders with Aspergers and Autism, two Autism Spectrum Disorders


It has been claimed that up to fifty percent of children with autism experience persistent gastrointestinal tract problems, ranging from mild to moderate degrees of inflammation in both the upper and lower intestinal tract. This has been described as a syndrome, autistic enterocolitis, by Dr. Andrew Wakefield; this diagnostic terminology, however, has been questioned by medical experts. Constipation, often with overflow, or encopresis, is often associated with developmental disorders in children, and is often difficult to resolve, especially among those with behavioral and communication problems. Click here strategies to deal with constipation.


'leaky gut' theory of autism

This high prevalence of gastrointestinal tract problems has led some to claim this is one of the causes of Autism. Many autistic individuals have permeable intestinal tracts, often referred to as ‘leaky gut.’ Suggested causes for this include viral infection such as measles, an overgrowth of yeast (candida albicans), and a reduction in phenol sulfur transferase which normally lines the intestinal tract. Some proponents of the leaky gut theory also theorize that heavy metals could be a cause.


The 'leaky gut' theory proposes that some children are unable to digest the protein in many cereals (gluten) or in milk (casein) completely. It claims that casein and gluten proteins aren't properly broken down and lead to a build up of opioids in the body, leading to high pain tolerance, repetitive behaviors and lack of concentration. A gluten and casein-free diet is believed by some parents of autistic children to aid in reducing symptoms of autism, Asperger's syndrome and other Autism Spectrum Disorders.


As with many aspects of Autism, there is much research needed in this area, but there is a growing consensus that gastrointestinal tract problems are a comorbid disorder with autism Spectrum Disorders, not an actual cause. Some parents claim that biomedical interventions such as the gluten-free casein-free diet have had varying degrees of benefit for their child. This fact sheet covers some of the controversy around this theory.


Autistic enterocolitis

Autistic enterocolitis is a controversial condition first reported by British gastroenterologist Dr. Andrew Wakefield to describe a number of common clinical symptoms and signs which he contends is distinctive to autism. There are numerous medical conditions comorbid to Autism Spectrum Disorders, with colitis perhaps the most prevalent. Up to fifty percent of children with Autism Spectrum Disorders experience persistent gastrointestinal problems, with mild to moderate degrees of inflammation in both the upper and lower intestinal tract. The term is starting to come into wider use as other researchers examine enterocolitis in autism.


Background to persistent gastrointestinal tract problems

Until the 1970s, autism was considered a very rare condition, but it is diagnosed much more often nowadays, whether due to increased diagnostic vigilance by doctors, changes of diagnostic categories, or an actual increase in incidence. Estimates of the percentage of late-onset autism cases range from 20% to 80%, with the lower percentage reported by sources including the British Medical Journal as not having changed in recent years. Wakefield, however, contends that a regressive syndrome "may reflect a subset of children with developmental disorders with distinct etiological and clinical features."


Despite others describing common bowel features, there have been no peer reviewed studies yet published, as of 2006, corroborating the existence of autistic enterocolitis; other studies have explicitly denied its existence. Thus, it is not generally accepted that the types of colitis found in autism are unique to autism. To date, no adequately controlled study has been published comparing the gut pathology of autistic and non-autistic children.


The Lancet study

When Wakefield and his colleagues first reported in 1998 a possible association between autistic regression, IBD, and MMR vaccines in the Lancet, they evaluated a dozen children with pervasive developmental disorders, apparent developmental regression, and intestinal symptoms, referred to the Royal Free Hospital.


Onset of behavioral symptoms was linked to recent (within two weeks) immunization with MMR vaccine in six of the children diagnosed with autism. An autism diagnosis was not linked to MMR vaccination, or the link was tenuous, in the remaining six. The most consistent finding was lymphoid nodular hyperplasia of the terminal ileum in nine of the children. This feature has also been reported in non-autistic children. A variety of colonic and rectal mucosal abnormalities was seen in eight cases. Biopsies of the ileum showed reactive lymphoid follicular hyperplasia in seven. Biopsies of the colon showed a diffuse mononuclear cell infiltrate in six.


Wakefield and his colleagues say they have described features of regressive autism with bowel disorders, or autistic enterocolitis, although these findings have been questioned:

* A vast majority of the children have chronic swelling of the lymphoid tissue lining the intestines, particularly near where the small and large intestines meet, and chronic inflammation of the large intestine, producing abdominal pain and alternating constipation and diarrhea.
* Affected children exhibit impaired cellular immunity to common recall antigens; the numbers of circulating white blood cells are low.
* A specific measles protein signal has been detected in immune cells of inflamed lymphoid tissue; another such indication is that affected children often have raised levels of measles-specific antibodies in their bloodstream.
* A loss of speech and language accompanied by symptoms of excessive thirst, bowel disturbances, self-injury, and a self-limited diet associated with cravings for particular foods.
* Allergies, food intolerances, and recurrent upper respiratory tract infections unresponsive to conventional treatments are also prominent features of this sub-group.


IBD and regressive autism

Although also characterized by intestinal lymphoid tissue disease activity, the primary symptoms and diagnostic criteria of the syndrome are behavioral and developmental. Age, dose of infection and the interaction of two or more viruses are claimed to be factors leading to regressive autism. According to Wakefield, "it is possible that the emergence of this new type of autism is related to a different pattern of exposure to environmental triggers." Abnormal metabolites of macro-nutriments have been found in the urine of autistic children, suggesting an incomplete or insufficient intra-intestinal digestion.


Potential link to MMR vaccinations

Central to one of the most acrimonious controversies in autism, Wakefield has hypothesized that autistic enterocolitis is an emergent IBD phenotype that follows from the increased incidence of low-dose compound viral exposures, i.e., exposures associated with the vast increase in the number of vaccinations given to children during a period when their immune systems are rapidly developing. Specifically, Wakefield asserts the autistic enterocolitis syndrome involves increased permeation of neurotoxic substances across the blood-brain barrier during a vulnerable part of brain development, leading to regressive autism. Other research, however, rejects this. Researchers have identified a high incidence of bowel symptoms in autistic children before the MMR vaccine was licensed.


"Retraction of an interpretation"

The Lancet paper has been widely cited as an impetus for concerns regarding the MMR vaccine being a cause of autism. Wakefield gave interviews after the publication of the paper, including on 60 Minutes where he raised concerns regarding administration of the MMR vaccine. In the Lancet paper, Wakefield and his co-authors said on the issue:


"We did not prove an association between measles, mumps, and rubella vaccine and the syndrome described. Virological studies are underway that may help to resolve this issue".


In 2004, ten of the authors issued a statement in the Lancet (2004;363:750) entitled "Retraction of an interpretation". In it the authors recommended first that work continue into their new discovery of intestinal problems of autistic children, saying:


"The main thrust of this paper was the first description of an unexpected intestinal lesion in the children reported. Further evidence has been forthcoming in studies from the Royal Free Centre for Paediatric Gastroenterology and other groups to support and extend these findings. While much uncertainty remains about the nature of these changes, we believe it important that such work continues, as autistic children can potentially be helped by recognition and treatment of gastrointestinal problems."


The authors went on to say that they retracted the "interpretation placed upon" their findings but the statement did not retract the findings themselves:


"We wish to make it clear that in this paper no causal link was established between MMR vaccine and autism as the data were insufficient. However, the possibility of such a link was raised and consequent events have had major implications for public health. In view of this, we consider now is the appropriate time that we should together formally retract the interpretation placed upon these findings in the paper, according to precedent."


Some view the decision as a means whereby the co-authors could dissociate themselves from the implication that there was a conclusion that there was any association at all. Others view it as an endeavor to disassociate the primary research into intestinal problems from the MMR/autism controversy so that original work could continue for the benefit of autistic children. Despite the statement the study findings still are always referenced in studies that test the hypothesis of MMR being a cause of autism.

The editor of the Lancet and the authors were taken aback by the furor that arose and the attention the paper received after publication.


Just before the retraction of an interpretation, criticism arose over the fact that the Royal Free Hospital had received £55 000,00 in August 1996 from lawyers preparing to sue MMR manufacturers for support of Dr. Wakefield's research. Later, Wakefield asserted that the donation was to fund a second clinical study; some of the children involved were subjects in both studies.

Wakefield currently faces disciplinary charges before the General Medical Council over the conduct of his research.


In October 2005, the Cochrane Library published its analysis of 31 "high quality" medical studies which concluded no link could be found between the MMR vaccine and bowel disease, autism or other pervasive developmental disorders. To increase the rigor of the meta-analysis, the criteria of the meta-analysis excluded smaller studies and studies that had the potential for bias. Wakefield's work was specifically excluded in the meta-analysis due to small sample size. With regard to the vaccine, Cochrane said that its survey of research "strongly supports its use."


Close autism fact sheet on gastointestinal problems and the leaky gut theory of Autism

Click here for the full range of Asperger's and autism fact sheets at www.autism-help.org
Click here to read the Allergies and Food Sensitivities fact sheet
Click here to read the Brain chemistry and autism fact sheet

This autism fact sheet is licensed under the GNU Free Documentation. It is derivative of an autism and Asperger's syndrome-related articles at http://en.wikipedia.org

Autistic enterocolitis is a controversial condition see frequently in children with Asperger's and Autism. It is sometimes called the 'leaky gut' theory and believes gastrointestinal disorders are a cause of Autism and Aspergers.