Final answer:
The causes of autism spectrum disorder (ASD) are largely unknown, but it is thought to be a disease of incorrect brain wiring. Variants of several genes correlate with the presence of ASD, but the specific mutations required for the disease vary among individuals. Claims linking ASD to prenatal lithium, prenatal depression, encephalitis caused by herpes virus, multiple sclerosis, and being born in the winter months have not been supported by scientific research. Additionally, the claim linking autism to vaccines has been debunked.
Step-by-step explanation:
Except for some well-characterized, clearly genetic forms of autism, the causes of autism spectrum disorder (ASD) are largely unknown. While variants of several genes have been correlated with the presence of ASD, the specific mutations required for the development of the disease vary among individuals. At a general level, ASD is thought to be a disease of "incorrect" brain wiring, with some ASD patients lacking the same level of synaptic pruning that occurs in non-affected individuals.
There have been claims suggesting a link between autism and prenatal lithium, prenatal depression, encephalitis caused by herpes virus, multiple sclerosis, and being born in the winter months, but scientific research has not found sufficient evidence to support these claims. It's important to note that a research paper linking autism to a common vaccine given to children in the 1990s was retracted due to fraudulent data, and subsequent studies have found no connection between vaccines and autism.
Overall, the causes of autism are complex, involving a combination of genetic and environmental factors that are still not fully understood.