Autism recent studies

Economic costs for adverse reproductive and developmental outcomes are noteworthy and expected to grow. Annual costs for infertility treatment in the United States exceed one billion dollars (U.S. Congress 1988). According to the Centers for Disease Control and Prevention (CDC), the cost to society for developmental defects is massive (i.e., the lifetime costs for children bom annually with 17 of the most common birth defects and cerebral palsy is over 8 billion (CDC 1995)). However, these abnormalities affect only 22% of children with birth defects, and the cost estimate does not consider costs associated with many other developmental disorders. A recent study estimated the total lifetime costs for persons bom in 1996 with mental retardation, autism, or cerebral palsy to be 47 billion, 4.9 billion, and 12 billion, respectively (Honeycutt et al. 1999). 

Controversially, some have claimed a connection between the use of thimerosal in vaccines and the apparent rise in the incidence of autism. However, recent studies have shown no association between thimerosal exposure and autism. ... 

It is suggested here that the dramatic increase in autism in California is due to environmental factors. The highly populated areas of California have poor air and water quality, contain numerous neurotoxic chemicals, 60 641 and are in close proximity to numerous Superfund sitesJ751 This is particularly the case in the Los Angeles area. The recent study connecting increased autism prevalence to maternal organochlorine pesticide exposure in rural California areas 59 supports the relationship between exposures to environmental pollutants and autism. Residents of urban areas are... 

Recent studies have reported that galantamine also improves the cognitive performance of patients with autism (Nicolson et al., 2006) and, unlike other cholinesterase inhibitors, decreases the negative symptoms in patients with schizophrenia (Schubert et al., 2006). Eor more severe Alzheimer s disease, memantine, an antagonist of N-methyl-D-aspartate (NMDA) receptors, has also been approved. A number of newer drugs undergoing clinical trials for Alzheimer s disease work by a variety of other mechanisms, although a common theme appears to be neuroprotection (Robertson and Mucke, 2006). 

Neurons operate under unique redox conditions, increasing their vulnerability to oxidative stress, and recent studies provide evidence of oxidative stress and neuroinflammation in autism. Impaired methylation is a consequence of oxidative stress, mediated in major part by inhibition of the folate- and cobalamin-dependent enzyme methionine synthase. Since methionine synthase activity is essential for dopamine-stimulated phospholipid methylation, some symptoms of autism may reflect impairment of this process. For example, dopamine D4 receptor activation... 

A 2004 report by the Institute of Medicine s Immunization Safety Review Committee concluded that available evidence favored rejection of a causal relation between thimerosal-containing vaccines and autism. In like manner, a recent retrospective cohort study conducted by the CDC did not support a causal association between early prenatal or postnatal exposure to mercury from thimerosal-containing vaccines and neuropsychological functioning later in childhood. 

In recent years several research papers have attributed an increase in autism to the introduction of the triple vaccine. This has led to a decreased public confidence in the vaccine. Detailed examination of the literature, and also the results of several clinical studies, have now indicated that there is no association between use of the triple vaccine and autism. This is backed up by over 20 years of successful deployment of the vaccine outside of the UK. Currently much effort is being made to restore confidence in the vaccine in order to avoid the lack of compliance leading to the occurrence of measles epidemics. 

In a recent review article on the anatomy of autism Amaral et al. (2008) point out that in these studies by Casanova and his colleagues, only 14 cases of autism, 9 of which had seizures and at least 10 with mental retardation, have been examined for minicolumn pathology. Consequently, more studies using a greater number of autistic brains with fewer other complications need to be carried out before any definite conclusions can be reached about changes that can only be attributed to autism. It would also be appropriate to examine brains in which the apical dendritic clusters and myelinated axon bundles have been stained to confirm the sizes of the minicolumns as detected in digitized images from autistic brains. 

In autism, a decrease in GAD67 protein levels as measured in whole cerebellar homogenates was initially reported (Fatemi et al., 2002), suggesting a decrease in GABAergic neurotransmission in the cerebellum. More recently, anatomical studies with in situ hybridization histochemistry have shown that GAD67 mRNA levels are also markedly decreased in Purkinje cells of autistic brains (Yip et al., 2007) (Fig. 2 /t<0.0001, two tailed f-test). 

In a recent in situ hybridization study, a 51% reduction in GAD65 mRNA levels was observed in a subpopulation of large neurons in dentate nucleus in five adult autism cases compared to six age- and PMI-matched controls (Yip et al., 2009). In contrast, in the same study, non-significant GAD65 mRNA levels were measured in a subpopulation of smaller dentate neurons in the same postmortem cases. 

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