Autism spectrum disorder genetics; a comprehensive review

Autism spectrum disorder (ASD) is a condition that is defined by difficulties in social interactions, communication challenges, and repetitive behaviors. ASD is a common condition, with a significant rise in the number of diagnosed children observed in recent decades. As of 2021, it is estimated that 1 in 44 children in the USA is affected by ASD. The disorder shows a notably higher prevalence in boys compared to girls, with a ratio exceeding four to one. Several genetic changes have been linked to ASD. Various common gene variations are believed to influence the likelihood of developing the condition. Genetic factors are estimated to contribute to 40-80 % of the overall risk associated with ASD. The combined risk from genetic variations along with environmental influences - such as older parental age, birth complications, and various unknown factors - determines an individual's likelihood of developing this intricate condition. Many of the genes associated with ASD play a role in processes related to brain development. The proteins encoded by these genes impact various elements of brain development, including the proliferation, growth, and organization of neurons and synaptogenesis. Some genes control the number of neurons produced, while others are essential for the development and functioning of synapses. Numerous studies have been conducted to investigate the relationship between genetic variants and the risk of ASD. In this article, we discuss the functions of key genes associated with synapse formation and environmental factors including valproic acid and immunological perturbation with the development of ASD.