Selected Autism Research Published in 2009
Evaluation, Diagnosis and Treatment of Gastrointestinal Disorders in Indviduals with ASD: A Consensus Report--Pediatrics, Buie et al (January 2010)
An expert panel says there's no rigorous evidence that digestive problems are more common in children with autism compared to other children, or that special diets work, contrary to claims by celebrities and vaccine naysayers
Incidence of Gastrointestinal Symptoms in Children With Autism: A Population-Based Study-- Pediatrics, Ibrahim, Voigt, Katusic, Weaver, and Barbaresi (August, 2009)
The Mayo Clinic study finds that autistic kids in the study were more likely than their nonautistic counterparts to be picky eaters or constipated. But the researchers did not find a significant difference between the two groups when it came to diarrhea, abdominal discomfort, bloating, reflux or vomiting.
According to Pediatrics, "as constipation and feeding issues/food selectivity often have a behavioral etiology, data suggest that a neurobehavioral rather than a primary organic gastrointestinal etiology may account for the higher incidence of these gastrointestinal symptoms in children with autism."
For years, parents, physicians and researchers have wondered whether people with autism suffered from more digestive problems than the rest of the population. Many autistic children are following aggressive medical regimens aimed at treating suspected gut trouble, including multiple nutritional supplements, and anti-fungal, anti viral and antibiotics medications. Some also are on a restrictive diet.
Study finds common risk factor for autism (April 2009)
Genome-Wide Analyses of Exonic Copy Number Variants in a Family-Based Study Point to Novel Autism Susceptibility Genes-- PLOS Genetics, Bucan M, Abrahams BS, Wang K, Glessner JT, Herman EI, et al.(June 2009)
The study identified 27 different genetic regions where rare copy number variations - missing or extra copies of DNA segments - were found in the genes of children with autism spectrum disorders, but not in the healthy controls.The researchers, including geneticists from the University of Pennsylvania School of Medicine and The Children's Hospital of Philadelphia (CHOP) compared genetic samples of 3,832 individuals from 912 families with multiple autistic children against genetic samples of 1,070 disease-free children. Besides the identification of 27 regions harboring rare variants in children with ASDs, the study also uncovered two novel genes where variations were found, BZRAP1 and MDGA2 - thought to be important in synaptic function and neurological development, respectively. Interestingly, key variants on these genes were passed down in some, but not all, of the affected individuals in families.
Lack of Efficacy of Citalopram in Children With Autism Spectrum Disorders and High Levels of Repetitive Behavior--Archives of General Psychiatry, King, Hollander, Sikich, McCracken, Scahill, Bregman, Donnelly, Anagnostou, Dukes, Sullivan, Hirtz, Wagner, Louise Ritz; for the STAART Psychopharmacology Network (June, 2009)
Citalopram (Celexa), a medication commonly prescribed to children with autism spectrum disorders (ASD), was no more effective than a placebo at reducing repetitive behaviors, according to a multi-site clinical trial guided by lead author Bryan King, MD, director of child and adolescent psychiatry at Seattle Children's Hospital and professor and vice chair of psychiatry at the University of Washington School of Medicine.
Because citalopram is also prescribed for patients with obsessive compulsive disorders (OCD), these study results may challenge the widely held premise that repetitive behaviors in children with ASD are similar to repetitive behaviors often found in cases of OCD. Read more.
High-density SNP association study of the 17q21 chromosomal region linked to autism identifies CACNA1G as a novel candidate gene--Molecular Psychiatry, Strom, Stone, Bosch, Merriman, Cantor, Geschwind, and Nelson, (May 2009)
(From a UCLA press release) UCLA scientists have discovered a variant of a gene called CACNA1G that may increase a child's risk of developing autism, particularly in boys. "We found that a common form of the gene occurs more frequently in the DNA of families that have two or more sons affected by autism, but no affected daughters," explained Dr. Stanley Nelson, professor of human genetics at the David Geffen School of Medicine at UCLA. The researchers traced the genetic markers to CACNA1G, which helps move calcium between the cells. They discovered that the gene has a common variant that appears in the DNA of nearly 40 percent of the population. "This alternate form of CACNA1G consistently increased the correlation to autism spectrum disorder, suggesting that inheriting the gene may heighten a child's risk of developing autism," observed Nelson. How the gene contributes to higher autism risk remains unclear, but Nelson emphasized that it cannot be considered a risk factor on its own. "This variant is a single piece of the puzzle," he said. "We need a larger sample size to identify all of the genes involved in autism and to solve the whole puzzle of this disease." The UCLA team's next step will be to sequence the gene in people who possess the altered variant in order to identify the exact change that increases autism risk. These subtle variations offer potential markers for the real mutation causing greater susceptibility to the disease.
Abstracts from the International Meeting for Autism Research --International Meeting for Autism Research (May 2009)
Vaccine Refusal, Mandatory Immunization and the Risks of Vaccine-Preventable Diseases.-- New England Journal of Medicine. Omer, Salmon, Orenstein, deHart, Halsey. (May 2009)
Vaccines are among the most effective prevention tools available to clinicians. However, the success of an immunization program depends on high rates of acceptance and coverage. There is evidence of an increase in vaccine refusal in the United States and of geographic clustering of refusals that results in outbreaks. Children with exemptions from school immunization requirements (a measure of vaccine refusal) are at increased risk for measles and pertussis and can infect others who are too young to be vaccinated, cannot be vaccinated for medical reasons, or were vaccinated but did not have a sufficient immunologic response.
Newly Found Genetic Variation Linked to Autism -- Nature (April 2009)
A newly identified genetic variant could account for up to 15 percent of autism cases, say researchers who studied genes that are important in connecting brain cells. Researchers say the variant is carried by about 65 per cent of people with autism.
Researchers identify how PCBs may alter in utero, neonatal brain development
--PLoS-Biology, Pessah, et al (April, 2009)
In three new studies — including one appearing in the Public Library of Science - Biology (PLoS - Biology) — UC Davis researchers provide compelling evidence of how low levels of polychlorinated biphenyls (PCBs) alter the way brain cells develop.
The findings could explain at last — some 30 years after the toxic chemicals were banned in the United States — the associations between exposure of the developing nervous system to PCBs and behavioral deficits in children.
"Two-year-olds with autism orient to non-social contingencies rather than biological motion"
--Nature, Klin, Lin, Gorrindo, Ramsay, Jones. (March 2009)
Typically developing human infants preferentially attend to biological motion within the first days of life. This ability is highly conserved across species and is believed to be critical for filial attachment and for detection of predators. The neural underpinnings of biological motion perception are overlapping with brain regions involved in perception of basic social signals such as facial expression and gaze direction, and preferential attention to biological motion is seen as a precursor to the capacity for attributing intentions to others. However, in a serendipitous observation, we recently found that an infant with autism failed to recognize point-light displays of biological motion, but was instead highly sensitive to the presence of a non-social, physical contingency that occurred within the stimuli by chance. This observation raised the possibility that perception of biological motion may be altered in children with autism from a very early age, with cascading consequences for both social development and the lifelong impairments in social interaction that are a hallmark of autism spectrum disorders. Here we show that two-year-olds with autism fail to orient towards point-light displays of biological motion, and their viewing behaviour when watching these point-light displays can be explained instead as a response to non-social, physical contingencies—physical continimplications for understanding the altered neurodevelopmental trajectory of brain specialization in autism.
"Partial reversal of Rett Syndrome-like symptoms in MeCP2 mutant mice"
--PNAS, Sur, Tropea, Giacometti, et al. (February, 2009)
Rett Syndrome (RTT) is a severe form of X-linked mental retardation caused by mutations in the gene coding for methyl CpG-binding protein 2 (MECP2). Mice deficient in MeCP2 have a range of physiological and neurological abnormalities that mimic the human syndrome. Here we show that systemic treatment of MeCP2 mutant mice with an active peptide fragment of Insulin-like Growth Factor 1 (IGF-1) extends the life span of the mice, improves locomotor function, ameliorates breathing patterns, and reduces irregularity in heart rate. In addition, treatment with IGF-1 peptide increases brain weight of the mutant mice. Multiple measurements support the hypothesis that RTT results from a deficit in synaptic maturation in the brain: MeCP2 mutant mice have sparse dendritic spines and reduced PSD-95 in motor cortex pyramidal neurons, reduced synaptic amplitude in the same neurons, and protracted cortical plasticity in vivo. Treatment with IGF-1 peptide partially restores spine density and synaptic amplitude, increases PSD-95, and stabilizes cortical plasticity to wild-type levels. Our results thus strongly suggest IGF-1 as a candidate for pharmacological treatment of RTT and potentially of other CNS disorders caused by delayed synapse maturation.
"Vaccines and Autism: A Tale of Shifting Hypotheses"
--Clinical Infectious Diseases, Offit, Paul and Gerber, Jeffrey S. (Feb. 2009)
Although child vaccination rates remain high, some parental concern persists that vaccines might cause autism. Three specific hypotheses have been proposed: (1) the combination measles‐mumps‐rubella vaccine causes autism by damaging the intestinal lining, which allows the entrance of encephalopathic proteins; (2) thimerosal, an ethylmercury‐containing preservative in some vaccines, is toxic to the central nervous system; and (3) the simultaneous administration of multiple vaccines overwhelms or weakens the immune system. We will discuss the genesis of each of these theories and review the relevant epidemiological evidence.
A worldwide increase in the rate of autism diagnoses—likely driven by broadened diagnostic criteria and increased awareness—has fueled concerns that an environmental exposure like vaccines might cause autism. Theories for this putative association have centered on the measles‐mumps‐rubella (MMR) vaccine, thimerosal, and the large number of vaccines currently administered. However, both epidemiological and biological studies fail to support these claims.
"Neuropsychological performance 10 years after immunization in infancy with thimerosal-containing vaccines".
--Pediatrics, Tozzi AE, Bisiacchi P, Tarantino V, De Mei B, D'Elia L, Chariotti F, Salmaso S. (January 2009)
Thimerosal, a mercury compound used as a preservative in vaccines administered during infancy, has been suspected to affect neuropsychological development. We compared the neuropsychological performance, 10 years after vaccination, of 2 groups of children exposed randomly to different amounts of thimerosa through immunization. Children who were enrolled in an efficacy trial of pertussis vaccines in 1992–1993 were contacted in 2003. Two groups of children were identified, according to thimerosal content in vaccines assigned randomly in the first year of life (cumulative ethylmercury intake of 62.5 or 137.5 µg), and were compared with respect to neuropsychological outcomes. Eleven standardized neuropsychological tests, for a total of 24 outcomes, were administered to children during school hours. Mean scores of neuropsychological tests in the domains of memory and learning, attention, executive functions, visuospatial functions, language, and motor skills were compared according to thimerosal exposure and gender. Nearly 70% of the invited subjects participated in the neuropsychological assessment (N = 1403). Among the 24 neuropsychological outcomes that were evaluated, only 2 were significantly associated with thimerosal exposure. Girls with higher thimerosal intake had lower mean scores in the finger-tapping test with the dominant hand and in the Boston Naming Test. Given the large number of statistical comparisons performed, the few associations found between thimerosal exposure and neuropsychological development might be attributable to chance. The associations found, although statistically significant, were based on small differences in mean test scores, and their clinical relevance remains to be determined.
Newly Found Genetic Variation Linked to Autism --Nature, (April 28, 2009)
A newly identified genetic variant could account for up to 15 percent of autism cases, say researchers who studied genes that are important in connecting brain cells. Researchers say the variant is carried by about 65 per cent of people with autism.
