Study of the Relationship Between Tuberous Sclerosis Complex & ASD
From Journal of Child Neurology.
Virginia Wong MBBS, FRCP (London, Edinburgh), FHKAM (Paed), FHKCPaed, FRCPCH
There has been increasing awareness that there are behavioral phenotypes in tuberous sclerosis complex with neuropsychiatric symptom complex such as autistic disorder and attention-deficit hyperactivity disorder (ADHD).
However, the neurobiologic basis of autistic disorder in tuberous sclerosis complex is still unknown.
We studied two cohorts of children followed up since 1986 until 2003, one cohort with tuberous sclerosis complex and another cohort with autistic disorder, to determine the incidence of autistic disorder in tuberous sclerosis complex and the incidence of tuberous sclerosis complex in autistic disorder respectively.
We established a Tuberous Sclerosis Complex Registry in 1985 at the University of Hong Kong.
In 2004, 44 index cases (the male to female ratio was 0.75:1) were registered.
Three had a positive family history of tuberous sclerosis complex.
Thus, the total number of tuberous sclerosis complex cases was 47.
We adopted the diagnostic criteria of tuberous sclerosis complex for case ascertainment.
The period prevalence rate of tuberous sclerosis complex for children and adolescents aged = 20 years is 3.5 per 10,000 (on Hong Kong island, excluding the eastern region with 125,100 aged = 20 years in 2003).
Of 44 cases with tuberous sclerosis complex, 7 had autistic disorder.Thus, the incidence of autistic disorder in tuberous sclerosis complex is 16%. During the 17-year period (1986-2003), we collected a database of 753 children (668 boys and 84 girls; male to female ratio 8:1) with autistic disorder and pervasive developmental disorders. For all children with autistic disorder or pervasive developmental disorders, we routinely examined for any features of tuberous sclerosis complex by looking for neurocutaneous markers such as depigmented spots, which appear in 50% of children with tuberous sclerosis complex by the age of 2 years.
For those with infantile spasm or epilepsy, the clinical features of tuberous sclerosis complex were monitored regularly during follow-up.
Of these, seven had tuberous sclerosis complex.
Thus, the incidence of tuberous sclerosis complex in autistic disorder is 0.9%.
All of these children are mentally retarded, with moderate to severe grades in an intellectual assessment conducted by a clinical psychologist.
Future studies should be directed toward looking at the various behavioral phenotypes in tuberous sclerosis complex and defining these with standardized criteria to look for any real association with the underlying genetic mutation of TSC1 or TSC2 gene or even the site of tubers in the brain.
Widely Circulated No Vaccine – Autism Link Study Riddled With Inaccuracies, Radical Conclusions, Says National Autism Association
Drug-company proponent Dr. Eric Fombonne ignores scientific evidence, uses frivolous research to obtain desired findings
Nixa, MO – Dr. Eric Fombonne’s new Quebec study will soon be published in the July 2006 issue of Pediatrics. Fombonne, a thimerosal litigation expert witness on behalf of various pharmaceutical companies, will reportedly state that it is “very clear” there is no relationship between mercury-based thimerosal and the onset of autism.
According to the research group SafeMinds, Fombonne’s research is dangerously inaccurate:
The study looked at 27,749 students in grades kindergarten through 12th grade in a Montreal school district and found 187 cases of autism.
The vast majority of these cases (more than 90%) were born in years in which thimerosal vaccines were widely used for infants in Quebec, as they were in the US.
Only a tiny fraction of the autism students were born when thimerosal-free DTP and Hib vaccines were given, and these students may have been exposed to thimerosal from the Hepatitis B vaccine newly recommended for infants of foreign-born parents, which made up over one fourth of the greater Montreal population.
Dr. Fombonne wrongfully claims that large-population studies in the United States, England and Denmark also disprove a link between mercury and autism.
Although multiple respected researchers state otherwise, Dr.
Fombonne maintains the radical conclusion “there is no autism epidemic.”
He conveniently ignores the vast body of scientific evidence, which has shown that environmental factors such as mercury may have caused the increased number of autism diagnoses in the US and other countries.
Dr. Fombonne’s actions have historically been in the best interest of various pharmaceutical companies, not families with autism. Fombonne has also declared himself an expert witness in thimerosal-related litigation.
SafeMinds states, “Thimerosal is a serious poison that is harmful via inhalation, ingestion or contact with skin. Furthermore, thimerosal-containing vaccines elevate mercury levels in the body to a level where adverse neurological outcomes are known to occur. It is irresponsible for any pediatric doctor to justify injecting our children with mercury.
“The prevalence of all autism spectrum disorders (ASDs) has risen to 1 in 166 children in the past 20 years. Several independent federal agencies and respected scientists and researchers have received federal funds to investigate the autism epidemic and the biological plausibility of a link between mercury and ASDs. Multiple studies have indicated that there is a connection between childhood vaccines containing thimerosal and the incidence of autism. No conclusions have been made rejecting a link between mercury and autism.”
The National Autism Association (NAA), along with multiple advocacy groups and researchers, hope that Fombonne’s conflicts of interest will be disclosed in Pediatrics. “These significantly weak conclusions certainly work to Dr. Fombonne’s benefit. It is only appropriate that his partnership with pharmaceutical companies be revealed,” says Claire Bothwell, Board Chair of NAA.
For more information, visit www.nationalautism.org or www.safeminds.org.