What contributes significantly to the onset of autism?

The choice that identifies known causes of autism, including copy number variants and chromosomal problems, is correct because it highlights the role of genetic factors in the development of the disorder.

Research has shown that genetics play a crucial role in autism spectrum disorders, with certain genetic abnormalities, including microdeletions and duplications (collectively referred to as copy number variants), being consistently associated with an increased risk of autism. Additionally, chromosomal abnormalities, such as those seen in syndromes like Fragile X, are linked to a higher prevalence of autism traits. This genomic perspective emphasizes the importance of inherited factors and hereditary patterns observed in families with a history of autism.

In contrast, while environmental toxins, psychological factors, and genetic factors alone do contribute to the complexity of autism, they do not comprehensively account for the known scientific evidence regarding its onset. Understanding autism as a multifactorial condition includes recognizing the significant contributions of both genetic factors and specific genetic mutations, which makes the recognition of copy number variants and chromosomal problems particularly essential in discussing its etiology.