Curr Pediatr Res 2013 Volume 17 Issue 2 79 Curr Pediatr Res 2013; 17 (2): 79-83 ISSN 0971-9032 http://www.pediatricresearch.info Levels of heavy metal and trace element among children with Autism spectrum disorders. Adel Almogren 1 , Zahid Shakoor 2 , Abdulkareem Almomen 3 , Rana M.W. Hasanato 4 1 Department of Pathology, College of Medicine and University Hospitals, King Saud University, PO Box: 2925 Riyadh 11461, Kingdom of Saudi Arabia 2 Department of Pathology, College of Medicine and University Hospitals, King Saud University, Riyadh, Kingdom of Saudi Arabia 3 Department of Medicine, Division of Hematology / Oncology, College of Medicine and University Hospitals, King Saud University, Riyadh, Kingdom of Saudi Arabia 4 Department of Biochemistry, College of Medicine and University Hospitals, King Saud University, Riyadh, Kingdom of Saudi Arabia Abstract Persistent exposure to high levels of heavy metals and trace elements has been implicated in autism spectrum disorders (ASDs). This study was performed to investigate the levels of heavy metals and trace elements in hair samples of patients with ASDs. Retrospective analy- sis of data from 58 children with ASDs with the mean age of 6.31+ 4.12 years between Jan. 2004 and Oct. 2008 was performed at King Khalid University Hospital, Riyadh. Hair sam- ples were sent to Micro Trace Mineral Gmbh, Laboratory for Clinical and Environmental Analysis, Hersbruck, Germany for heavy metals and trace elements analysis. Acceptable laboratory reference ranges were used for interpretation of results. Majority of the children (93.1%) were males. Among the 13 heavy metals and trace elements detected in higher con- centrations uranium was present in 23 (39.6%), tellurium in 21 (36.2%), mercury in 15 (25.8%), strontium in 15 (25.8%), aluminum in 14 (24.1%) and nickel in 12 (20.6%) pa- tients. High levels of heavy metals and trace elements detected in Saudi children with ASDs indicate environmental exposure. Further investigations are recommended for assessment of the environmental hazard in the region. Keywords: Autism, Heavy metals, Mercury, Trace elements, Uranium. Accepted March 06 2013 Introduction Autism spectrum disorders (ASDs) are neuro- developmental childhood disorders of unknown etiology characterized by impaired verbal and nonverbal commu- nication and social interactions associated with stereo- typed patterns of behavior and interests [1]. Genetic and environmental factors have been implicated in the disor- der [2]. Exposure to heavy metals because of their poten- tial to cause developmental neurotoxicity is believed to be among the major risk factors [3,4]. Differential expression of a large number of genes has be shown to correlate with blood levels of lead and mercury in children with ASD [5,6]. High blood levels of mercury during various devel- opmental stages consequent to genetically reduced ability to excrete mercury has been shown to cause immunologi- cal, neurological and behavioral abnormalities very simi- lar to those seen in ASDs [7-9]. The likelihood of a com- bination of genetic and environmental factors especially exposure to metals in the etiology of ASDs therefore ap- pears to be strong and cannot be ignored. Because of the widespread environmental contamination of heavy metals it is rather difficult to avoid persistent exposure to metals. Although lead, cadmium, arsenic and aluminum have been implicated in ASDs but the evidence supporting mercury as an etiological agent is more con- vincing [10,11]. A study investigating relationship be- tween autism symptoms and body burden of toxic metals has revealed a significant positive association between the severity of autism and the relative body burden of toxic metals [12]. These observations gain further support from the fact that following chelation therapy for removal of heavy metals from the body almost all the patients with autism have been shown to exhibit clinical improvement [13]. It is therefore quite conceivable that apart from their