Background: Autism Spectrum Disorder (or Autism) is a neurodevelopmental and neurological condition, with prevalence of 1 in 100 children globally. This review examines the most common factors associated with Autism.

Methods: We conducted a scoping review of factors associated with an increased risk of developing Autism. These included genetic predisposition, parental age, gender, birth complications and morbidities due to other medical conditions.

Results: Evidence from twin studies shows a 90% genetic predisposition towards Autism - with 102 genes strongly associated with Autism, including SCN1A and SLC6A1. There are also genetic syndromes and chromosomal disorders associated with Autism, including Fragile X syndrome and Tuberous Sclerosis complex (TSC). Several studies have demonstrated an increased risk with advanced parental age (>35 years) (e.g., fathers >50 years are 2.2 times more likely to have a child with Autism than those <30 years). Other factors include infections during pregnancy (e.g. immune dysfunction) and gestational diabetes. Prematurity, such as low birth weight (<1500g) and low gestational age (<32 weeks) are also associated with an increased risk of Autism. With regard to gender, boys are more likely to be diagnosed with Autism - gender ratio of 3:1 and 4:1 has been reported in different populations. Abnormalities in brain development during early prenatal or postnatal periods may increase the risk of Autism. These abnormalities can lead to social, communication, and behavioural challenges characteristic of Autism.

Conclusions: Autism is a complex and heterogeneous condition that likely arises from a combination of factors such as genetic susceptibility and pre- and postnatal factors. An understanding of these factors is important for early detection, intervention, and support for children to improve their quality of life and reduce morbidity.