Autism Spectrum Disorders: The Association with Inherited Metabolic Disorders and Some Trace Elements. A Retrospective Study

Background: Autism Spectrum Disorders (ASD) as a considerable health obstacle in kids is characterized by compromised social collaboration and stereotyped behavior. Autism is triggered by an interactive impact of environmental and genetic influences. Presumably, some inborn errors of metabolism are implicated in a sector of developmental disabilities. Also, several trace elements may have an important role in human behavior and neurological development. This study was designed to verify the frequency of inherited metabolic disorders and/or trace element abnormalities in children with ASD. Methods: In a retrospective analytical study, 320 children diagnosed with ASD according to the DSM-V criteria and Childhood Autism Rating Scale criteria were enrolled in this study. Serum ammonia, blood lactate, and arterial blood gases, plasma amino acid profile by tandem mass spectrophotometry, and a urinary organic acid assay were performed in all the patients. Likewise, the estimation of a number of trace elements in the form of serum lead, mercury, copper, and plasma zinc was done in all the patients. Results: A total of 320 children with ASD, inherited metabolic disorders were identified in eight (2.5%) patients as follows: seven (2.19%) patients with phenylketonuria, and one (0.31%) patient with glutaric aciduria type 1. Regarding the trace element deficiency, sixteen (5%) patients presented low plasma zinc level, five (1.56%) children presented a high serum copper level, two (0.62%) children presented a high serum lead level and only one (0.31%) autistic child presented high serum mercury level. Electroencephalogram (EEG) abnormalities were reported in 13.12% and Magnetic Resonant Imaging (MRI) abnormalities in 8.43% of cases. Conclusion: Screening for metabolic diseases and trace elements is required in all children diagnosed with ASD irrespective of any apparent clinical attributes of metabolic complaints and trace elements discrepancies.