Rapamycin

Via Technovelgy:

Rapamycin, a drug approved by the FDA to stop tissue rejection after organ transplants, has been found to reverse the brain dysfunction caused by a genetic disease - tuberous sclerosis complex (TSC).
"This is the first study to demonstrate that the drug rapamycin can repair learning deficits related to a genetic mutation that causes autism in humans. The same mutation in animals produces learning disorders, which we were able to eliminate in adult mice," explained principal investigator Dr. Alcino Silva, professor of neurobiology and psychiatry at the David Geffen School of Medicine at UCLA. "Our work and other recent studies suggest that some forms of mental retardation can be reversed, even in the adult brain."

See Science Daily for more details.

Autism as Diagnostic Substitution

Half Sigma cites a two-year-old paper from Pediatrics to explain the autism "epidemic" as a change in diagnostic categories, rather than any known increase in the incidence of autism. The Contribution of Diagnostic Substitution to the Growing Administrative Prevalence of Autism in US Special Education reported the following results:

The average administrative prevalence of autism among children increased from 0.6 to 3.1 per 1000 from 1994 to 2003. By 2003, only 17 states had a special education prevalence of autism that was within the range of recent epidemiological estimates. During the same period, the prevalence of mental retardation and learning disabilities declined by 2.8 and 8.3 per 1000, respectively. Higher autism prevalence was significantly associated with corresponding declines in the prevalence of mental retardation and learning disabilities. The declining prevalence of mental retardation and learning disabilities from 1994 to 2003 represented a significant downward deflection in their preexisting trajectories of prevalence from 1984 to 1993. California was one of a handful of states that did not clearly follow this pattern.

Contagious Yawning

Via Gene Expression: Biology Letters reports "the disturbance of contagious yawning in individuals with autism spectrum disorder (ASD)."

Yawning video clips elicited more yawns in TD [typically developing] children than in children with ASD, but the frequency of yawns did not differ between groups when they observed control video clips. Moreover, TD children yawned more during or after the yawn video clips than the control video clips, but the type of video clips did not affect the amount of yawning in children with ASD. Current results suggest that contagious yawning is impaired in ASD, which may relate to their impairment in empathy. It supports the claim that contagious yawning is based on the capacity for empathy.

The news has already made it into the Wikipedia section on contagious yawning.

Autism and Vaccines Again

Via Gene Expression: the UK Times reports on the latest autism and MMR controversy.

One of the two team members reported as resurrecting the discredited theory that MMR causes autism is Dr Carol Stott, a developmental psychologist who once worked at ARC. Baron-Cohen says she left ARC some time ago. She is now listed as a member of staff at Thoughtful House, a research centre in developmental disorders in Texas. Thoughtful House is run by Dr Andrew Wakefield, the gastroenterologist who first raised the possibility of a MMR-autism link in 1998. The other figure named as having revived the MMR-autism link was Dr Fiona Scott, who still works at ARC as an honorary research associate and runs training courses on how to diagnose autism. Scott has issued a statement denying that she privately believes in any link between MMR and autism.
Baron-Cohen says the news story is alarmist and wrong. He does not believe that MMR has anything to do with autism. “We are gobsmacked, really, at how this draft report has got out,” Baron-Cohen says. “It was only in the hands of the authors – about half a dozen people. There are three professors listed, including me, and none of us was contacted. It was also seen by two PhD students for whom I have the utmost respect because they are very careful scientists.
“I don’t believe that the MMR vaccine causes autism and I don’t believe that there are hidden environmental reasons for any rise in cases. For the moment, we should assume [any rise] is more to do with diagnostic practice.”

Autism, Bipolar Disorder, and Schizophrenia

Via Gene Expression, a PNAS article that correlates susceptibility to 161 diseases, pairwise, with special attention to autism, bipolar disorder, and schizophrenia. They interpret the correlations as overlap in the genetic mechanisms of (susceptibility to) the various diseases.

Our analysis suggests that, instead of following the familiar model of ‘‘unique malady–unique (disjoint with others) set of broken genes’’ applicable to most Mendelian disorders (Fig. 2D), most complex phenotypes are probably rooted in genetic variation that is significantly shared (in either a competitive or cooperative manner) by multiple disease phenotypes (Fig. 2E).
Phenotypes of non-Mendelian disorders are often defined with a considerable degree of fuzziness, especially those that are neurological: it is not uncommon to define a neuropsychiatric disease phenotype as comprising, for example, at least five of a list of 10 symptoms (4). This fuzziness arises because, in many cases, the observed disease is a heterogeneous collection of multiple maladies that have partially similar symptoms and potentially different genetic causes. However, these genetically heterogeneous maladies are combined because of the history of disease identification and the incompleteness of our knowledge about the disease causes.
Our interpretation of genetic overlap among pairs of disorders does not exclude the possibility that one disorder can cause the other. For example, it is possible that comorbidity of autism (or schizophrenia, or bipolar disorder)with infectious and autoimmune maladies indicates that the neurodevelopmental disorder can be triggered by different developmental insults, including viral or bacterial infection, or an autoimmune disease launched by a benign allergen. Another possibility is that the same molecular features that make a child more susceptible to infection or to autoimmune attack have a pleiotropic effect on brain development and function.

For the full list of overlaps, see the appendices. Appendix 1 has more pretty pictures, while 4 and 5 have some easier-to-read tables. Here's the pretty picture for plague (click to enlarge):

Thimerosal

Via GNXP: The Journal of American Physicians and Surgeons (Spring 2006) documents Early Downward Trends in Neurodevelopmental Disorders Following Removal of Thimerosal-Containing Vaccines:

Contemporaneously with the epidemic rise in neuro-developmental disorders (NDs), first observed in the United States during the 1990s, the childhood immunization schedule was expanded by the U.S. Centers for Disease Control and Prevention (CDC) to include several additional thimerosal-containing vaccines (TCVs). On July 7, 1999, a joint recommendation was made by the American Academy of Pediatrics (AAP) and the U.S. Public Health Service (PHS) to remove thimerosal from vaccines. A two-phase study was undertaken to evaluate trends in diagnosis of new NDs entered into the Vaccine Adverse Event Reporting System (VAERS) and the California Department of Developmental Services (CDDS) databases on a reporting quarter basis, from 1994 through 2005. Significant increasing trends in newly diagnosed NDs were observed in both databases 1994 through mid-2002. Significant decreasing trends in newly diagnosed NDs were observed in both databases from mid-2002 through 2005. The results indicate that the trends in newly diagnosed NDs correspond directly to the expansion and subsequent contraction of the cumulative mercury dose to which children were exposed from TCVs through the U.S. immunization schedule.

Autism Again

MedicineNet reports that yet another study has failed to link autism to vaccines. I'd like to see some studies on the assortative mating theory.

Sad Child Disease

Here's an article by two doctors about autism and vaccines. The alleged culprit is thimerosal (sodium ethylmercurithiosalicylate - note the mecur[y]), a preservative used in some vaccines. The CDC claims that no one is using thimerosal anymore, and it doesn't cause autism, and the dates for the surge in autism and the introduction of thimerosal don't match, anyway.

The doctors claim that autism and similar developmental difficulties were unheard-of before thimerosal. The theory is mercury poisoning: the affected children are unable to excrete the mercury that comes to them from vaccines and maternal dental amalgams. The CDC is eliminating thimerosal (as a precaution, not an admission of its guilt), but the article claims that "vaccines containing 25 mcg of mercury per dose and carrying an expiration date of 2005 continue to be produced and administered."

The occasion of this article is pending legislation in California to ban thimerosal in vaccines (beyond trace levels) for both children and mothers by July 2006. Whether or not it passes, it seems that thimerosal and mercury dental amalgams are on their way out. If the autism rate then drops suddenly, I'll become a believer.