Blood Lead Level, Urinary Porphobilinogen and Serum Acetylcholine in Nigerian Children with Autism Spectrum Disorder

Abstract

Purpose: Autism spectrum disorder (ASD), a common neurodevelopmental disorder characterized by communication and behavioral deficits, remains a subject of unknown etiology. However, the interplay of heavy metal toxicity and altered neurotransmission have been implicated in the development of ASD. Therefore, this study examined blood lead level (BLL), serum acetylcholine (ACh), and urine porphobilinogen (PBG) levels in Nigerian children with ASD. Methods: Forty participants aged 3 to 12 years were recruited, including 14 children diagnosed with ASD (cases), 13 children with neurodevelopmental disorders (NDDs) excluding ASD (positive controls), and 13 neurotypical children (negative controls). BLL was measured using atomic absorption spectroscopy (AAS), while serum ACh and urinary PBG levels were assessed using ELISA and modified Mauzerall-Granick methods, respectively. Results: The study revealed no significant difference in BLL between the cases and controls. However, urinary PBG levels were significantly higher cases (4.03 ± 0.57 µmol/mmol creatinine) compared to negative controls (3.29 ± 0.46 µmol/mmol creatinine). Additionally, the study found significantly lower serum ACh levels in the cases (588.55 ± 239.09 pg/mL) and positive controls (439.10 ± 260.69 pg/mL) compared to the negative controls (843.19 ± 339.63 pg/mL). Importantly, no significant correlation was found between BLL, PBG, and ACh. Conclusion: The study findings suggest potential chronic metal toxicity and altered cholinergic neurotransmission may play a role in the etiology of ASD. Further research is needed to explore the specific mechanism.