Transmethylation and Oxidative Biomarkers in Children with Autism Spectrum Disorder: A Cross Sectional Study.

Researchers studied blood and urine markers in 119 autistic children compared to 52 typically developing children. They found that autistic children had higher levels of homocysteine (a substance in blood) and dityrosine (a marker of cell damage). About 13% of autistic children had high homocysteine levels compared to only 4% of typical children. These differences weren't related to how severe the autism was or other behavioral issues.

This cross-sectional study compared biomarkers related to transmethylation, oxidative stress, and mitochondrial function between 119 children with ASD and 52 typically developing controls. Key findings included significantly elevated serum homocysteine levels in the ASD group (9 μmol/L vs 7 μmol/L) and higher prevalence of hyperhomocysteinemia (13.4% vs 3.8%). Dityrosine levels, a marker of oxidative stress, were also significantly higher in ASD children (9.8 vs 2.2 counts per second). Other biomarkers including cysteine, methionine, uric acid, lactate, vitamins E and B12, folate, and protein modifications showed no significant differences.

No correlations were found between biomarker levels and autism severity, developmental quotients, or behavioral issues.

Findings suggest possible metabolic differences in autism involving transmethylation and oxidative stress pathways. However, clinical utility remains unclear as biomarkers didn't correlate with symptom severity. Further research needed before considering routine screening or targeted interventions based on these biomarkers.

Cross-sectional design prevents causal inferences. Sample size relatively small for subgroup analyses. Exclusion criteria may limit generalizability. No information provided about dietary factors that could influence biomarker levels. Limited assessment of potential confounding variables.

We aimed to investigate the potential role of biomarkers of transmethylation, oxidative stress, and mitochondrial dysfunction in children with Autism Spectrum Disorder (ASD) by comparing them with that of typically developing children (TDC) controls. We also tried to correlate them with severity of autism, sensory issues, behavioural comorbidities and developmental quotients 119 with ASD and 52 age and sex matched typically developing children (TDC) controls were enrolled excluding those with chronic-illness or on any antioxidant therapy/multivitamins/anti-epileptic drugs. Median levels of biomarkers - serum homocysteine, cysteine, methionine, urine uric acid-to-creatinine ratio, arterial lactate, serum vitamin E, vitamin B12, folate, Nε-carboxymethyllysine, Nω- carboxymethylarginine (CMA), dityrosine and MTHFR C677T polymorphism were calculated. Children with ASD were further characterised using Childhood Autism Rating Scale-2, Childhood behavioural checklist, child sensory profile 2 caregiver questionnaire, Developmental Profile 3 for any correlation with the various biomarker levels.

The median level of serum homocysteine in ASD group was 9 μmol/L(Range, 7- 16μmol/L), which was significantly higher than controls 7 μmol/L(Range, 4- 11μmol/L)(p=0.01). The prevalence of hyper-homocystinemia(>15μmol/L) was 13.4% in ASD as compared to 3.8% in controls with a significant difference(p=0.04). Dityrosine level was higher among ASD children when compared to TDC (9.8 vs 2.2 counts per second(cps), p<0.001). No significant correlation was found between prevalence of hyperhomocysteinemia and severity of autism/DQ/behavioural issues.

No significant difference was found between the median levels of other biomarkers. Results support possible role of transmethylation defects and oxidative stress in ASD pathogenesis. Further studies are warranted for a better understanding of ASD pathogenesis.