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Pica, object-mouthing, Mercury, Zinc, MT Protein, Why boys more likely to get autism... US National Library of Medicine

Posted by on Oct. 15, 2012 at 4:46 PM
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I'M sharing this journal paper from US National Library of Medicine. It's an interesting article that covers many topics. I stumbled on it researching my son's problem with object-mouthing and zinc and other vitamin/mineral deficiencies...

Introduction

Autistic spectrum disorder (ASD) is a neurodevelopmental syndrome with onset prior to age 36 months. Diagnostic criteria consist of impairments in sociality and communication plus repetitive and stereotypic behaviors.1 Traits strongly associated with autism include movement disorders and sensory dysfunctions.2 Although autism may be apparent soon after birth, most autistic children experience at least several months, up to a year or more in some cases, of normal development, followed by regression, defined as loss of function or failure to progress.24

The neurotoxicity of mercury (Hg) has long been recognized.5 Primary data come from victims of contaminated fish or grain, from acrodynia induced by Hg in teething powders, and from individual instances of mercury poisoning (HgP), many occurring in occupational settings. More recently, the Food and Drug Administration (FDA) and the American Academy of Pediatrics (AAP) have determined that the typical amount of Hg injected into infants and toddlers via childhood immunizations has exceeded government safety guidelines on an individual6 and cumulative vaccine basis.7 The mercury in vaccines derives from thimerosal (TMS), a preservative which is 49.6% ethylmercury (eHg).7 There may be an association between mercury toxicity and the onset of autism.4,810 This association is still unclear, however, since there are several recent reports showing no relationship between mercury exposure and autism.1113

The metallothioneins (MT) are a family of small proteins containing 61–68 amino acids with an unusually high concentration of cysteine (30%). MT-1, the most functional and active MT in humans, has 21 cysteines. Cysteine contains a sulfhydryl group (SH) that has the ability to react with a number of metals including zinc, mercury, copper and cadmium.

Divalent metals such as copper, zinc, and manganese are toxic to cells in elemental or ionic form. These metals are “enveloped” or “bound” to the small linear MT, which supervises and regulates metal levels in blood, brain and the periphery and therefore plays a major role in heavy metal detoxification of these metals.1417

Besides detoxification of heavy metals, functions of MT in the body include development of brain neurons, maturation of the GI tract, antioxidation, boosting immune function and delivery of zinc to cells.14,1820 Evidence also suggests that autistic individuals are prone to developing autoimmune disorders and autism appears to be more common in families with a history of autoimmune disorders.2124

MT dysfunction may result, then, in many of the issues seen with autistic children, such as the leaky gut syndrome, incomplete breakdown of casein/gluten protein by zinc-dependent enzymes, disrupted ability to combat yeast, reduced production of stomach acid, and impaired stimulation of the pancreas by secretin. It may also lead to inability to clear the body of heavy metals, a dysfunctional immune system, and ultimately to the neurological changes seen in ASD. It would also explain the male sex predominance (4:1) seen in autism, because MT synthesis is enhanced by estrogen and progesterone. In a study of 503 autism-spectrum patients at The Pfeiffer Treatment Center, scientists found abnormal levels of copper and zinc in blood indicating defective functioning of MT proteins.25

MT levels fluctuate in direct response to heavy metal levels such as zinc.26 The fluctuation of MT levels and/or the production of abnormally structured MT in autistic individuals may stimulate an autoimmune response.

In this study, we tested the hypothesis that levels of MT and anti-MT IgG might be associated with gastrointestinal (GI) disease, particularly inflammation, found in many autistic children.

The rest of the journal paper can be seen at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3108685/

by on Oct. 15, 2012 at 4:46 PM
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