Yektaş C, et al. - In this single-center, cross-sectional, case-control study, researchers examined the serum concentrations of vitamin B12, vitamin B9 (folate) and homocysteine in children diagnosed with attention deficit hyperactivity disorder (ADHD) or autism spectrum disorder (ASD) and healthy controls. In 118 children, the levels of serum vitamin B12, folate and homocysteine were measured. No connections were found between psychometric evaluations and laboratory measurements in ASD children. The authors discovered that vitamin B12 and homocysteine differed significantly in patients with ADHD and ASD and healthy control children. They observed that ASD patients had the lowest level of vitamin B12 and the highest level of homocysteine. No significant difference was found in serum folate levels both in ASD and ADHD group vs control group. Children's gender and age did not have any significant impact on vitamin levels.