Level of Trace Elements (Copper, Zinc, Magnesium and Selenium) and Toxic Elements (Lead and Mercury) in the Hair and Nail of Children with Autism
TL;DR: The study observed a valid indication of Cu body burden in the autistic children and showed a significant elevation in the concentration of Cu, Pb, and Hg and significant decrease in the concentrate of Mg and Se observed in the hair and nail samples of autistic subjects could be well correlated with their degrees of severity.
Abstract: Autism is a multi-factorial pathology observed in children with altered levels of essential and elevated levels of toxic elements. There are also studies reporting a decrease in nutritional trace elements in the hair and nail of autistic children with healthy controls; moreover, bioelements have been shown to play an important role in the central nervous system. Therefore, the purpose of the present study was to assess the levels of trace elements like copper (Cu), zinc (Zn), magnesium (Mg), and selenium (Se) and toxic elements like mercury (Hg), and lead (Pb) in the hair and nail samples of autistic children and to evaluate whether the level of these elements could be correlated with the severity of autism. The subjects of the study were 45 autistic children with different grades of severity (low (LFA), medium (MFA), and high (HFA) functioning autism) according to Childhood Autism Rating Scale, n = 15 children in each group and 50 healthy children (age and sex matched). The boys and girls ratio involved in this study was 4:1, and they were 4-12 years of age. The study observed a valid indication of Cu body burden in the autistic children. The children with different grades of autism showed high significance (p < 0.001) in the level of copper in their hair and nail samples when compared to healthy controls. The level of Cu in the autistic children could be correlated with their degree of severity (more the Cu burden severe is autism). The study showed a significant elevation (p < 0.001) in the levels of toxic metals Pb and Hg in both hair and nail samples of autistic children when compared to healthy control group. The elevation was much pronounced in LFA group subjects when compared among autistic groups MFA and HFA. The levels of trace elements Mg and Se were significantly decreased (p < 0.001) in autistic children when compared to control. The trace element Zn showed significant variation in both hair and nails of LFA group children when compared to control group and other study groups. The significant elevation in the concentration of Cu, Pb, and Hg and significant decrease in the concentration of Mg and Se observed in the hair and nail samples of autistic subjects could be well correlated with their degrees of severity.
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TL;DR: The findings of this review suggest that the etiology of ASD may involve, at least in a subset of children, complex interactions between genetic factors and certain environmental toxicants that may act synergistically or in parallel during critical periods of neurodevelopment, in a manner that increases the likelihood of developing ASD.
Abstract: Although the involvement of genetic abnormalities in autism spectrum disorders (ASD) is well-accepted, recent studies point to an equal contribution by environmental factors, particularly environmental toxicants. However, these toxicant-related studies in ASD have not been systematically reviewed to date. Therefore, we compiled publications investigating potential associations between environmental toxicants and ASD and arranged these publications into the following three categories: (a) studies examining estimated toxicant exposures in the environment during the preconceptional, gestational and early childhood periods; (b) studies investigating biomarkers of toxicants; and (c) studies examining potential genetic susceptibilities to toxicants. A literature search of nine electronic scientific databases through November 2013 was performed. In the first category examining ASD risk and estimated toxicant exposures in the environment, the majority of studies (34/37; 92%) reported an association. Most of these studies were retrospective case–control, ecological or prospective cohort studies, although a few had weaker study designs (for example, case reports or series). Toxicants implicated in ASD included pesticides, phthalates, polychlorinated biphenyls (PCBs), solvents, toxic waste sites, air pollutants and heavy metals, with the strongest evidence found for air pollutants and pesticides. Gestational exposure to methylmercury (through fish exposure, one study) and childhood exposure to pollutants in water supplies (two studies) were not found to be associated with ASD risk. In the second category of studies investigating biomarkers of toxicants and ASD, a large number was dedicated to examining heavy metals. Such studies demonstrated mixed findings, with only 19 of 40 (47%) case–control studies reporting higher concentrations of heavy metals in blood, urine, hair, brain or teeth of children with ASD compared with controls. Other biomarker studies reported that solvent, phthalate and pesticide levels were associated with ASD, whereas PCB studies were mixed. Seven studies reported a relationship between autism severity and heavy metal biomarkers, suggesting evidence of a dose–effect relationship. Overall, the evidence linking biomarkers of toxicants with ASD (the second category) was weaker compared with the evidence associating estimated exposures to toxicants in the environment and ASD risk (the first category) because many of the biomarker studies contained small sample sizes and the relationships between biomarkers and ASD were inconsistent across studies. Regarding the third category of studies investigating potential genetic susceptibilities to toxicants, 10 unique studies examined polymorphisms in genes associated with increased susceptibilities to toxicants, with 8 studies reporting that such polymorphisms were more common in ASD individuals (or their mothers, 1 study) compared with controls (one study examined multiple polymorphisms). Genes implicated in these studies included paraoxonase (PON1, three of five studies), glutathione S-transferase (GSTM1 and GSTP1, three of four studies), δ-aminolevulinic acid dehydratase (one study), SLC11A3 (one study) and the metal regulatory transcription factor 1 (one of two studies). Notably, many of the reviewed studies had significant limitations, including lack of replication, limited sample sizes, retrospective design, recall and publication biases, inadequate matching of cases and controls, and the use of nonstandard tools to diagnose ASD. The findings of this review suggest that the etiology of ASD may involve, at least in a subset of children, complex interactions between genetic factors and certain environmental toxicants that may act synergistically or in parallel during critical periods of neurodevelopment, in a manner that increases the likelihood of developing ASD. Because of the limitations of many of the reviewed studies, additional high-quality epidemiological studies concerning environmental toxicants and ASD are warranted to confirm and clarify many of these findings.
379 citations
18 Nov 2015
TL;DR: In this article, the authors integrate life history, evolutionary psychology, and human biology approaches to address the question of how and why our minds generate different levels of attraction to others, and identify different domains of social value for which attractiveness assessment evolved, and review evidence for some of the hypothesized attractiveness-assessment adaptations in those domains.
Abstract: How and why do our minds generate different levels of attraction to others? This chapter integrates life history, evolutionary psychology, and human biology approaches to address this question. Biological adaptations regulate a vast number of life history trade-offs that affect how we look, smell, sound, and behave. Selection produced adaptations that evaluate these cues and regulate our degree of attraction to others based on their relative probable social value to us in different contexts. This chapter outlinesthe alternative evolutionary explanations for the emergence of an attraction,basic components necessary for attraction systems to evolve, and sources of variation in attractiveness assessment. It identifies different domains of social value for which attractiveness assessment evolved, reviews evidence for some of the hypothesized attractiveness-assessment adaptations in those domains, and highlights avenues calling for increased attention. Finally, it calls for greater integration of evolutionary psychology, human biological research, and data from small-scale foraging societies to generate predictions about these domains of social value, the cues or signals associated with them, adaptations selected to regulate attraction to them, and the life history trade-offs involved in these processes. New research on body shape attractiveness is presented to illustrate these points.
Keywords:
attractiveness;
life history;
beauty;
social value;
waist-to-hip ratio;
body shape
243 citations
TL;DR: There is genetic and biochemical evidence for a mitochondria (mt) role in the pathogenesis of ASD in a subset of children and a need for further research using the latest genetic technology such as next-generation sequencing, microarrays, bioinformatics, and biochemical assays.
213 citations
TL;DR: A model is proposed that interconnects the most important and scientifically recognized environmental factors and similarities in how these risk factors impact synapse function are discussed and a possible influence on an already well described genetic pathway leading to the development of autism via zinc homeostasis is proposed.
Abstract: Autism is a neurodevelopmental disorders characterized by impairments in communication and social behavior, and by repetitive behaviors. Although genetic factors might be largely responsible for the occurrence of autism they cannot fully account for all cases and it is likely that in addition to a certain combination of autism-related genes, specific environmental factors might act as risk factors triggering the development of autism. Thus, the role of environmental factors in autism is an important area of research and recent data will be discussed in this review. Interestingly, the results show that many environmental risk factors are interrelated and their identification and comparison might unveil a common scheme of alterations on a contextual as well as molecular level. For example, both, disruption in the immune system and in zinc homeostasis may affect synaptic transmission in autism. Thus, here, a model is proposed that interconnects the most important and scientifically recognized environmental factors. Moreover, similarities in how these risk factors impact synapse function are discussed and a possible influence on an already well described genetic pathway leading to the development of autism via zinc homeostasis is proposed.
181 citations
Cites background from "Level of Trace Elements (Copper, Zi..."
...Former studies describe a significant elevation of Cu2+ in the hair and nail samples of subjects with autism (Lakshmi Priya and Geetha, 2011)....
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TL;DR: This manuscript reviews the reports of a multidisciplinary national meeting on endocrine disrupting chemicals and suggests effects of EDCs on prenatal growth, thyroid function, glucose metabolism and obesity, puberty, fertility, and on carcinogenesis mainly through epigenetic mechanisms.
Abstract: Wildlife has often presented and suggested the effects of endocrine disrupting chemicals (EDCs). Animal studies have given us an important opportunity to understand the mechanisms of action of many chemicals on the endocrine system and on neurodevelopment and behaviour, and to evaluate the effects of doses, time and duration of exposure. Although results are sometimes conflicting because of confounding factors, epidemiological studies in humans suggest effects of EDCs on prenatal growth, thyroid function, glucose metabolism and obesity, puberty, fertility, and on carcinogenesis mainly through epigenetic mechanisms. This manuscript reviews the reports of a multidisciplinary national meeting on this topic.
177 citations
References
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TL;DR: This review focuses on the inherited disorders in humans that directly affect copper or iron homeostasis in the brain and the molecular genetic basis of these rare disorders has provided insight into the mechanisms of copper and iron acquisition, trafficking, storage, and excretion in thebrain.
Abstract: Copper and iron are transition elements essential for life. These metals are required to maintain the brain's biochemistry such that deficiency or excess of either copper or iron results in central nervous system disease. This review focuses on the inherited disorders in humans that directly affect copper or iron homeostasis in the brain. Elucidation of the molecular genetic basis of these rare disorders has provided insight into the mechanisms of copper and iron acquisition, trafficking, storage, and excretion in the brain. This knowledge permits a greater understanding of copper and iron roles in neurobiology and neurologic disease and may allow for the development of therapeutic approaches where aberrant metal homeostasis is implicated in disease pathogenesis.
498 citations
"Level of Trace Elements (Copper, Zi..." refers background in this paper
...It is well known that copper is one of many metal ions that are required for essential body functions but are toxic in excess quantity [23]....
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TL;DR: Six candidate broader phenotype autism traits are proposed and it is argued that knowledge of the cognitive neuroscience of social and language behavior will provide a useful framework for defining such measures.
Abstract: Achieving progress in understanding the cause, nature, and treatment of autism requires an integration of concepts, approaches, and empirical findings from genetic, cognitive neuroscience, animal, and clinical studies. The need for such integration has been a fundamental tenet of the discipline of developmental psychopathology from its inception. It is likely that the discovery of autism susceptibility genes will depend on the development of dimensional measures of broader phenotype autism traits. It is argued that knowledge of the cognitive neuroscience of social and language behavior will provide a useful framework for defining such measures. In this article, the current state of knowledge of the cognitive neuroscience of social and language impairments in autism is reviewed. Following from this, six candidate broader phenotype autism traits are proposed: (a) face processing, including structural encoding of facial features and face movements, such as eye gaze; (b) social affiliation or sensitivity to social reward, pertaining to the social motivational impairments found in autism; (c) motor imitation ability, particularly imitation of body actions; (d) memory, specifically those aspects of memory mediated by the medial temporal lobe–prefrontal circuits; (e) executive function, especially planning and flexibility; and (f) Language ability, particularly those aspects of language that overlap with specific language impairment, namely, phonological processing.
405 citations
"Level of Trace Elements (Copper, Zi..." refers background in this paper
...Progress in understanding the causes, nature, and treatment for autism requires ever-increasing integration between concepts, genetic findings, advances in cognitive neuroscience and clinical observations [3]....
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TL;DR: A review of the identification and assessment process for children with autism and autistic spectrum disorder is presented in this article, where the authors discuss the identification, assessment, and early intervention of children with ASD.
Abstract: *
Parents want autism to be diagnosed as early as possible, and early intervention may improve long term outcomes. The authors of this review discuss the identification and assessment process for children with autism and autistic spectrum disorder
Autistic spectrum disorders have been the subject of increasing attention over the past few years–from the media, from clinicians, and from the general public. Stories of savants who excel in such skills as calendar calculations and detailed drawings have long been a fascination to public and clinician alike, exemplified in Dustin Hoffman's portrayal of a young man with autism in the film Rainman . Most recently, public anxiety about autism has been raised as a result of reports linking the measles, mumps, and rubella (MMR) vaccine with autism and inflammatory bowel disorder and a rise in the prevalence of autism.1 2 This has resulted in a serious fall in immunisation rates,3 despite the epidemiological evidence of a lack of association,4 and strong reassurance from the Department of Health and the Royal College of Paediatrics and Child Health about the safety of the MMR vaccine. Parents of children with autism continue to express the view that the medical profession does not take their concerns about possible causes of autism seriously. “Miracle cures” for autism–for example, with secretin–have received wide publicity through television and raised enormous hopes before being placed in their proper context by double blind trials that have not confirmed a curative effect. We consulted recent reviews, specialist journals, and recent Medline papers on the diagnosis of autism.
Autism is a behaviourally defined disorder, characterised by qualitative impairments in social communication, social interaction, and social imagination, with a restricted range of interests and often stereotyped repetitive behaviours and mannerisms. Sensory hyposensitivities or hypersensitivities to the environment are common features. …
310 citations
"Level of Trace Elements (Copper, Zi..." refers background in this paper
...Autism is a behaviorally defined disorder, characterized by qualitative impairments in social communication, social interaction, and social imagination, with a restricted range of interests and often stereotyped repetitive behaviors and mannerisms [1]....
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TL;DR: It is shown that ABC does not distinguish individuals with autistic disorders from other cases of developmental disorders as well as CARS: the number of false negatives is high (46%) with ABC as opposed to 0% with CARS.
Abstract: Childhood Autism Rating Scale (CARS) and Autism Behavior Checklist (ABC) are tests widely used for screening and diagnosis of autism This study verified their correspondence and conflict with a diagnosis made with DSM-IV criteria The sample consisted of 65 children, aged 18 months to 11 years We found complete agreement between DSM-IV and CARS We show that ABC does not distinguish individuals with autistic disorders from other cases of developmental disorders as well as CARS: the number of false negatives is high (46%) with ABC as opposed to 0% with CARS
227 citations
"Level of Trace Elements (Copper, Zi..." refers background in this paper
...The scale evaluates behavior in 14 domains that are generally affected in autism, plus a single category for general impression of autism [16]....
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TL;DR: Baby teeth are a good measure of cumulative exposure to toxic metals during fetal development and early infancy, so this study suggests that children with autism had a higher body burden of mercury during fetal/infant development.
Abstract: This study determined the level of mercury, lead, and zinc in baby teeth of children with autism spectrum disorder (n = 15, age 6.1 ± 2.2 yr) and typically developing children (n = 11, age = 7 ± 1.7 yr). Children with autism had significantly (2.1-fold) higher levels of mercury but similar levels of lead and similar levels of zinc. Children with autism also had significantly higher usage of oral antibiotics during their first 12 mo of life, and possibly higher usage of oral antibiotics during their first 36 mo of life. Baby teeth are a good measure of cumulative exposure to toxic metals during fetal development and early infancy, so this study suggests that children with autism had a higher body burden of mercury during fetal/infant development. Antibiotic use is known to almost completely inhibit excretion of mercury in rats due to alteration of gut flora. Thus, higher use of oral antiobiotics in the children with autism may have reduced their ability to excrete mercury, and hence may partially explain t...
187 citations
"Level of Trace Elements (Copper, Zi..." refers background in this paper
...One environmental factor that has received significant attention is the burden of mercury, lead, and other toxic metals [4]....
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