Title : Biomarkers of neurotoxicity in the management of autism spectrum disorders in an underdeveloped economy

Autism Spectrum Disorders (ASD) are neurodevelopmental disorders (NDDs) characterized by impairments in communication and social interaction along with restrictive and repetitive behaviours beginning in infancy and toddler years. The diagnosis of this disorder remains a medical challenge due to equivocal results of genetic mappings even in advanced economies. However, exploration of epigenetic factors as possible prognostic markers of ASD management especially in less developed economies where genetic mapping may be difficult becomes imperative; this is the focus of this work.Twenty-three children (23) (aged 3-12years) clinically diagnosed by Consultant Paediatric Neurologist and Child Psychiatrist using DMS-IV method as cases and Thirty (30) normotypical children as controls were recruited for this study. Levels of essential (Ca, Mg, Mn, Zn, Cu, Fe, V and Se) and toxic (Cd, Al, Pb) metals were determined using ICP-MS while levels of oxidative markers (malondialdehyde (MDA), total plasma peroxidase (TPP), and total antioxidant capacity (TAC)) and levels of neurotransmitters in recruited children were also determined using standard biochemical methods.

Mean plasma calcium and magnesium levels was significantly reduced in children with ASD (7.90 ± 0.17 mg/dl, 2.44 ± 0.07 mg/dl) in comparison to the controls (8.97 ± 0.20 mg/dl (P < 0.001; P < 0.000 and P < 0.002; P < 0.000) respectively. However, mean lead levels in children with CP (10.38 ± 1.45 μg/dl) were significantly greater than in ASD (7.92 ± 1.30 μg/dl) and normal children The mean plasma lead and vanadium levels were (7.92 ± 1.30 µg/dl; 1.07 ± 0.22 µg/dl) and (6.83 ± 0.72 µg/dl; 2.59 ± 0.48 µg/dl) in children with ASD and in controls respectively. The result showed that blood lead level in ASD was slightly increased but not significant when compared with control (p < 0.433). On the other hand, plasma vanadium concentration in ASD was significantly reduced (1.07 ± 0.22 µg/dl) when compared with control (2.59 ± 0.48 µg/dl) (P<0.038). Mean plasma copper was similar in all participants (1.98 ± 0.13, 2.23± 0.12) but selenium concentrations were significantly reduced (0.37 ± 0.05 mg/L; 0.57 ± 0.02 mg/L) in ASD relative to controls respectively.

The levels of TPP and TAC were significantly reduced while MDA was higher in ASD compared to NT. Although OSI was higher in ASD, the difference was not significant. Pb (lead) concentration was significantly increased while Mg, Zn, and Cu levels were reduced significantly in ASD compared to NT. A significant negative correlation between Mg and OSI (r = − 0.438; p = 0.029) was observed in NT.

Application of above biochemical data may suffice as an interim measure in the management of Neurodevelopmental disorder (ASD) especially in underdeveloped economy where facilities for advance scientific processes may not be available.

To be updated shortly..