Genetic predisposition and the role of homocysteine in a female with late diagnosis of autism

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by deficits in social interaction and communication, as well as restricted and repetitive behaviors. Although ASD often manifests during early childhood, many individuals are diagnosed later in life due to difficulties in meeting increasing social demands. Early diagnosis and personalized treatment are crucial in lifetime ASD symptom trajectories. We report the case of a 27-year-old woman diagnosed with ASD in adulthood, in correlation with elevated homocysteine (Hcy) levels due to homozygosity for the MTHFR C677T polymorphism, whose symptoms deteriorated, possibly related to dietary changes. Following Hcy blood levels normalization, autistic symptoms of social interaction improved. This case highlights a potential relationship between environmental factors, such as dietary changes, and the late diagnosis of ASD, supporting the theory that interaction between environment and genetics, possibly, plays a role in ASD development.