title: Altered urinary porphyrins and mercury exposure as biomarkers for autism severity in Egyptian children with autism spectrum disorder.
abstract: Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder that affects social, communication, and behavioral development. Recent evidence supported but also questioned the hypothetical role of compounds containing mercury (Hg) as contributors to the development of ASD. Specific alterations in the urinary excretion of porphyrin-containing ring catabolites have been associated with exposure to Hg in ASD patients. In the present study, the level of urinary porphyrins, as biomarkers of Hg toxicity in children with ASD, was evaluated, and its correlation with severity of the autistic behavior further explored. A total of 100 children was enrolled in the present study. They were classified into three groups: children with ASD (40), healthy controls (40), and healthy siblings of the ASD children (20). Children with ASD were diagnosed using DSM-IV-TR, ADI-R, and CARS tests. Urinary porphyrins were evaluated within the three groups using high-performance liquid chromatography (HPLC), after plasma evaluation of mercury (Hg) and lead (Pb) in the same groups. Results showed that children with ASD had significantly higher levels of Hg, Pb, and the porphyrins pentacarboxyporphyrin, coproporphyrin, precoproporphyrin, uroporphyrins, and hexacarboxyporphyrin compared to healthy controls and healthy siblings of the ASD children. However, there was no significant statistical difference in the level of heptacarboxyporphyrin among the three groups, while a significant positive correlation between the levels of coproporphyrin and precoproporphyrin and autism severity was observed. Mothers of ASD children showed a higher percentage of dental amalgam restorations compared to the mothers of healthy controls suggesting that high Hg levels in children with ASD may relate to the increased exposure to Hg from maternal dental amalgam during pregnancy and lactation. The results showed that the ASD children in the present study had increased blood Hg and Pb levels compared with healthy control children indicating that disordered porphyrin metabolism might interfere with the pathology associated with the autistic neurologic phenotype. The present study indicates that coproporphyrin and precoproporhyrin may be utilized as possible biomarkers for heavy metal exposure and autism severity in children with ASD.
authors.affiliation: Department of Pediatric, Al-Azhar University, Cairo, Egypt.
authors.forename: Eman M
authors.initials: EM
authors.lastname: Khaled
authors.affiliation: Department of Research on Children with Special Needs, National Research Centre, Giza, Egypt.
authors.forename: Nagwa A
authors.initials: NA
authors.lastname: Meguid
authors.affiliation: Council for Nutritional and Environmental Medicine, Toften 24, 8610, Mo i Rana, Norway. bjorklund@conem.org.
authors.forename: Geir
authors.identifier: 0000-0003-2632-3935
authors.initials: G
authors.lastname: Bjørklund
authors.affiliation: Department of Genetic Biochemistry, National Research Centre, Giza, Egypt.
authors.forename: Amr
authors.initials: A
authors.lastname: Gouda
authors.affiliation: Department of Psychiatry, Al-Azhar University, Cairo, Egypt.
authors.forename: Mohamed H
authors.initials: MH
authors.lastname: Bahary
authors.affiliation: Department of Research on Children with Special Needs, National Research Centre, Giza, Egypt.
authors.forename: Adel
authors.initials: A
authors.lastname: Hashish
authors.affiliation: Department of Research on Children with Special Needs, National Research Centre, Giza, Egypt.
authors.forename: Nermin M
authors.initials: NM
authors.lastname: Sallam
authors.affiliation: University Laboratory of Medical Research, Department of Medicine, University of Verona, Verona, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Chirumbolo
authors.affiliation: Department of Medical Biochemistry, National Research Centre, Giza, Egypt.
authors.forename: Mona A
authors.initials: MA
authors.lastname: El-Bana
mesh_terms: D000293:Adolescent; D000067877:Autism Spectrum Disorder / Q000097:blood* / Q000453:epidemiology / Q000652:urine*; D015415:Biomarkers / Q000652:urine; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D004534:Egypt / Q000453:epidemiology; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008628:Mercury / Q000097:blood* / Q000633:toxicity; D011166:Porphyrins / Q000652:urine*; D012720:Severity of Illness Index
chemical_list: D015415:Biomarkers; D011166:Porphyrins; D008628:Mercury
keywords: Autism; Mercury exposure; Toxicity biomarkers; Urinary porphyrins