g.   Vision

In autism, one of the earliest signs detected by mothers is a lack of eye contact (Gillberg & Coleman, 1992), and an early diagnostic behavior is failure to engage in joint attention based on the ability to “look where you are pointing” (CHAT, Baron-Cohenet al, 1992).  Of 11 autistic children studied, ten had inaccurate or slow visual saccades (Rosenhall et al, 1988).  Although some adults with ASD report exceptional visual acuity, visual problems are common, with two separate studies reporting 50% of ASDsubjects having some type of unusual visual impairment (Steffenburg, in Gillberg & Coleman, 1992).  Ritvo et al (1986) and Creel et al (1989) found decreased function of the rods in a study of autistic people, including a retinal sheen, and noted that many such individuals tend to use peripheral vision because of this.  A number of case reports describe over-sensitivity to light and blurred vision (Sperry, 1998; Gillberg & Coleman, 1992, p.29; O’Neill & Jones, 1997).
Mercury can lead to a variety of vision problems, especially in children (Pierce et al, 1972; Snyder, 1972).  Children who ate high doses of mercury from contaminated pork developed blindness (Snyder, 1972).  In Iraqi babies exposed prenatally there was blindness or impaired vision (Amin-Zaki,1974 and 1979).  Iraqi children exposed postnatally developed visual disturbances, which ranged from blurred or hazy vision to constriction of the visual fields to complete blindness (Amin-Zaki et al, 1978).  Two girls with mercury vapor poisoning were found to have visual field defects (Snyder, 1972), and, as previously noted, one child with Hg poisoning developed gaze avoidance (Fagala & Wigg, 1992).  Acrodynia sufferers report vision problems, including near-sightedness and light sensitivity or photophobia (Diner and Brenner, 1998; Neville Recollection, Pink Disease site; Farnesworth, 1997; Matheson et al, 1980; Aronow and Fleischmann, 1976).  A 25 year old man with elemental mercury poisoning exhibited decreased visual acuity, difficulty with visual fixation, and constricted visual fields (Kark et al, 1971).  In Japanese victims, there was blurred vision as well as constriction of visual fields (Snyder, 1972; Tokuomi et al, 1982).  Iraqi mothers exposed to Hg had visual disturbance (Amin-Zaki, 1979).
In dogs exposed to daily doses of methylmercury, distortion of the visual evoked response from the visual cortex was the first sign.  Damage occurred in the preclinical silent stage, demonstrating that CNS damage is occurring before overt symptoms appear (Mattsson et al, 1981).  Monkeys treated at birth with low level methylmercury exhibited impaired spatial vision and visual acuity at age 3 and 4 years (Rice and Gilbert, 1982).  Disturbances caused by methylmercury in rat optic nerves were observed (Kinoshita et al, 1999).

h.   Physical Presentations

There is a much higher rate of autism among children with cerebral palsy than would be expected by chance (Nordin and Gillberg, 1996).  Many autistic children have abnormal muscle tone including hyper- and hypotonia, and many are incontinent or have difficulty being toilet trained (Filipek et al, 1999; Church and Coplan, 1995).  Several of the infants which Teitelbaum and colleagues (1998) observed showed decreased arm strength, and Schuler (1995) describes greater muscle weakness in the upper than the lower body.  Impairments in oral-motor function, including problems chewing and swallowing, are common, as noted previously.
These impairments are seen in mercurialism as well. In the Iraqi and Japanese epidemics, many children developed clinical cerebral palsy (Amin-Zaki, 1979; Myers & Davidson, 1998; Gilbert & Grant-Webster 1995; Dale, 1972).  Amin-Zaki et al (1978) reported muscle wasting and lack of motor power and control in most cases, complete paralysis in several cases, and athetotic movements in 2 cases, of postnatally exposed children.  In the Iraqi babies and children, some had increased muscle tone, while others had decreased muscle tone.  Abnormal reflexes, spasticity, and weakness were common.  One child said “my hands are weak and do not obey me” (Amin-Zaki et al, 1974 and 1978). The 12 year old who inhaled mercury vapor exhibited weakness and decreased muscle strength (Fagala and Wigg, 1992). As in autism, muscle weakness from mercury poisoning is most prominent in the upper body (Adams et al, 1983). Acrodynia, for example, is marked by poor muscle tone in general and loss of arm strength in particular (Farnesworth, 1997). Finally, difficulty in chewing and swallowing, salivation, and drooling are common in children as well as adults; incontinence was observed in children in the Iraqi Hg-crisis (Amin-Zaki, 1974 and 1978; Pierce et al, 1972; Snyder, 1972; Joselow et al, 1972; Smith, 1977).
The presence of rashes and dermatitis is sometimes reported in descriptions of ASD subjects.  Whiteley et al (1998) found that 63% of the ASD children had a history of eczema or other skin complaints.“Some children with autism are frequent scratchers. Gentle rubbing and scratching can become a calming self-stimulation; but when it becomes clawing, and there are rashes and open scrapes on the skin, a tactile intolerance can be responsible” (O’Neill, 1999).
Rashes and itching are common disturbances in mercury toxicity as well (Kark et al, 1971).  A 4 year old with Hg poisoning developed an itchy, peeling rash on the extremities (Florentine and Sanfilippo, 1991).  Mercury vapor inhalation caused a rash and peeling on the palms and soles of a pre-adolescent (Fagala and Wigg, 1992).  An acrodynia victim described himself as a child as having severe itching and a constant burning sensation at the extremities, resulting in him rubbing his hands and feet raw (Neville Recollection, Pink Disease Support Group).  Acrodynia symptoms in anadult poisoned by ethylmercury injection included pink scaling palms and soles, flushed cheeks, and itching (Matheson et al, 1980).  In acrodynia the skin may be rough and dry, and the soles and palms are usually but not necessarily red (Aronow and Fleischmann, 1976).  Thimerosal ingested by 44 year old man led to dermatitis (Pfab et al, 1996).
In autism, “signs of autonomic disturbance may be noticed at times, including sweating, irregular breathing, and rapid pulse” (Wing and Attwood, 1987). There may be elevated blood flow and heart rate (Ornitz, 1987).  An increased incidence of acrocyanosis has been observed in Asperger’s syndrome.  Acrocyanosis is an uncommon disorder of poor circulation in which skin on the hands and feet turn red and blue; there is profuse sweating; and the fingers and toes are persistently cold (Carpenter and Morris, 1991).
Sweating and circulatory abnormalities are also common in some forms of mercury poisoning.  Acrodynia in adults and children results in excessive sweating, poor circulation, and rapid heart rate (Farnesworth, 1997; Matheson et al, 1980; Cloarec et al, 1995; Warkany and Hubbard, 1953).  The 12 year old with mercury vapor poisoning sweated profusely, especially at night (Fagala and Wigg, 1992), and elevated blood pressure has been reported in exposed workers (Vroom and Greer, 1972).  Autonomic system abnormalities can be caused by disturbances in acetylcholine levels, known to be deficient in both autism and Hg poisoning (see neurotransmitter section below).

j.      Gastrointestinal Function

Many if not most autistic individuals have gastrointestinal problems, the most common complaints being chronic diarrhea, constipation, gaseousness, and abdominal discomfort and distention (D’Eufemia et al, 1996; Horvath et al, 1999; Whitely et al, 1998).  Colitis is not uncommon (Wakefield et al, 1998).  As noted previously, anorexia is sometimes associated with ASD (Gillberg & Coleman, 1992).  Kanner noted that over half his initial cases had feeding difficulties and excessive vomiting as infants (1943).  O'Reilly and Waring (1993) have described sulfur deficiencies in autism, an effect of which can be clumping of proteins on the gut wall, which is lined with sulfated proteins. The clumping can lead to increased intestinal permeability, or leaky gut syndrome (Shattock, 1997), found in many autistic individuals (D'Eufemia, 1996). Some ASD individuals have unusual opioid peptide fragments in urine; these peptides are believed to enter the bloodstream due to a leaky gut and to resultfrom an incomplete breakdown of gluten and casein in the diet possibly arising from "inadequacy of the [endopeptidase] enzyme systems which are responsible for their breakdown" (Shattock, 1997).
Mercury, which binds to sulfur groups (Clarkson, 1992), is known to cause gastroenteritis (Kark et al, 1971).  For example, a four year old with diarrhea was initially diagnosed with gastroenteritis (Florentine and Sanfilippo, 1991).  A pre-adolescent with mercury vapor poisoning developed nausea, abdominal pain, poor appetite, rectal itching, and diarrhea; she frequently strained to have a bowel movement, and was at one point diagnosed with colitis (Fagala and Wigg, 1992).  Acrodynia is marked by both constipation and diarrhea (Diner and Brenner, 1998).  Incontinence of urine and stool are observed in infants and children exposed pre- and postnatally in Iraq (Amin-Zaki, 1974 and 1978).  In another case, a 28 year old woman with occupational exposure to mercury vapor developed watery stools (Ross et al, 1977).  Diarrhea and digestive disturbance were seen in a dentist with measurable mercury levels; there was obesity in another dentist (Smith, 1977).  A 44 year old man poisoned with thimerosal given intramuscularly developed gastrointestinal bleeding, which looked like hemorrhaging colitis (Lowell et al, 1996).  Intense exposure to mercury vapor can cause abdominal pain, nausea, and vomiting (Feldman, 1982).  Severe constipation, anorexia, weight loss, and other “disturbances of gastrointestinal function” have been noted in other cases (Adams et al, 1983; Joselow et al, 1972).  Rats tested with mercuric chloride were observed with “lesions of the ileum and colon with abnormal deposits of IgA in the basement membranes of the intestinal glands and of IgG in the basement membranes of the lamina propria” (Andres, 1984, reviewed in EPA, 1997, p.3-36).  In another rat experiment, Hg was found to increase the permeability of intestinal epithelial tissues (Watzl et al, 1999). Mercury also inhibits the peptidase - dipeptidyl peptidase IV -  which cleaves, among other substances, casomorphin during the digestive process (Puschel et al, 1982).
There is no reported increase in incidence in kidney problems in autism.  Although renal function is commonly impaired from Hg exposure, such impairment would not be expected if the mercury exposure occurred from thimerosal injections, since kidney function may be unaffected when mercury is injected or inhaled (Davis et al, 1994; Fagala and Wigg, 1992).  For example, although thimerosal ingested orally by a 44 year old man resulted in renal tubular failure and gingivitis (Pfab et al, 1996), renal function was normal in another 44 year old man injected intramuscularly with thimerosal (Lowell et al, 1996).

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