The Environmental and Genetic Causes of Autism [2016] by James Lyons-Weiler

The Environmental and Genetic Causes of Autism [2016] by James Lyons-Weiler

Author:James Lyons-Weiler
Language: eng
Format: azw3
Tags: Autism, Vax - Risk Awareness
ISBN: 9781510710863
Publisher: Skyhorse
Published: 2016-11-29T05:00:00+00:00


Gadow et al. (2014) found the variation at the rs6311 locus was associated with the severity of depression in children with ASD. Abdelrahman et al. (2014) found that the G allele and the GG genotype at rs6311 (also known as 1438A/G polymorphism) of the 5-HT2A receptor gene were observed more frequently in children with autism than control. They also found a significant increase of homozygote A allele of the –1438A/G and CC genotype of the 102T/C polymorphism in ASD children with gastrointestinal disorders (GIDs) in autism.

Other variants in HTR2A are found to be associated with IQ, intellectual disability (ID), and language onset delay within ASD (Hervás et al., 2014).

A class of drugs called 5-HT2a antagonist have shown efficacy in treating bipolar disorder in Asperger syndrome patients (Vannucchi et al., 2014). The benefits included improved psychotic and behavioral symptoms and reduced social withdrawal. Mestre et al. (2013) reviewed the literature on the efficacy of 5-HT2a antagonists and reported little clinical impact on schizophrenia, depression, anxiety, obsessive compulsive disorder, and psychosis in Parkinson’s disease or Alzheimer’s disease. Biomarker-directed treatment may improve efficacy. Indiscriminate use of drugs on an entire population with high genetic and etiologic heterogeneity is not likely to be fruitful.

SEROTONIN TRANSPORTERS

The role of serotonin receptors in autism has been well studied. Studies have found association of variation with autism (e.g., Kim et al., 2002). Serotonin transporters modulate serotonin levels and localization. Event-related potentials (the reaction of the brain to stimuli) have been shown to be different in adults with ASD than neurotypicals when shown emotional facial expressions, and, interestingly, a specific variant in the serotonin transporter was also found to have a distinct neurological response (Faja et al., 2016). The serotonin transporter genotype of autistics determines (in part) the degree and rate of amygdala habituation to sad faces (Wiggins et al., 2014). Variants in serotonin transporter gene promoters have been found to be associated with self-injury in ASD (Kolevzon et al., 2014). Variation in serotonin in the blood of autistics can be caused by genes that regulate serotonin, transporters, and receptors (Hranilović et al., 2009).

ALUMINUM AND SEROTONIN

Cumulative exposure to aluminum in vaccines is a serious concern. Laabbar et al. (2014) found that aluminum caused increased serotonin levels in the dorsal raphe nucleus; however, they did not check the isoform produced. Given that mutations leading to the long isoform are associated with autism, future studies should measure isoform levels, not overall serotonin.

Lithium may be a neuroprotectant against oral aluminum neurotoxicity (Laabbar et al. 2014), although it can have some serious side effects.

SELECTIVE SEROTONIN UPTAKE INHIBITORS

In a study of prenatal exposure to selective serotonin uptake inhibitors, El Marroun et al. (2012) found that the use of selective serotonin uptake inhibitors is associated with autism, a number of autistic traits, and affective (social) phenotypes measured by the Social Responsiveness Scale. They also found that exposure to prenatal maternal depression was associated with PDD symptoms, but to a lesser degree. Numerous other studies have confirmed this observation (e.g., Gidaya et al., 2014). Gentile (2015)



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