Autism spectrum disorder (ASD) is a complex neurodevelopmental condition prevalent among children aged 3-8 years. Its etiology involves a combination of genetic and environmental factors. Research indicates that oxidative stress and low levels of the antioxidant glutathione may disrupt methylation-dependent epigenetic regulation, impacting neurodevelopment.

Recent studies suggest that Vitamin D deficiency during pregnancy and early childhood could be an environmental risk factor for ASD. Vitamin D plays crucial roles in brain development, immunological modulation, antioxidation, anti-apoptosis, neural differentiation, and gene regulation. Children with ASD often have lower serum levels of 25-hydroxy Vitamin D compared to healthy children.

Despite its genetic basis, ASD is primarily diagnosed based on behavioral characteristics. Instruments like the Autism Diagnostic Observation Schedule-Generic (ADOS) assess impairments in language, social interaction, and repetitive behaviors across different developmental levels.

Interestingly, the prevalence of Vitamin D deficiency aligns with the rise in ASD diagnoses over the past two decades, potentially linked to reduced sun exposure following medical advice.

Vitamin D deficiency is not limited to regions with limited sunshine; it is also prevalent in sun-rich areas like the Asia-Pacific, Africa, and the Middle East. This deficiency is commonly observed among populations with mental health issues, pregnant women, asthmatic children, and diabetic children.

In conclusion, while ASD has a strong genetic component, understanding its epidemiology requires considering environmental factors such as Vitamin D deficiency, which could influence its prevalence and severity.

Reference:
Bener, Abdulbari, Azhar O. Khattab, and Mohamad M. Al-Dabbagh. “Is high prevalence of Vitamin D deficiency evidence for autism disorder? In a highly endogamous population.”