For autism causes, experts look to genes, not vaccines

Earlier this year, Health and Human Services Secretary Robert F. Kennedy Jr. pledged that the search for autism's cause — a question that has kept researchers busy for the better part of six decades — would be over in just five months.

- BY CORINNE PURTILL

ANTHONY CAMERANO Associated Press RESEARCHERS have found hundreds of genes that could be linked to autism. There may be many more.

"By September, we will know what has caused the autism epidemic, and we'll be able to eliminate those exposures," Kennedy told President Trump during a Cabinet meeting in April.

That ambitious deadline has come and gone. But researchers and advocates say that Kennedy's continued fixation on autism's origins - and his frequent, inaccurate claims that childhood vaccines are somehow involved - is built on fundamental misunderstandings of the complex neurodevelopmental condition.

Even after more than half a century of research, no one yet knows exactly why some people have autistic traits and others do not, or why autism spectrum disorder looks so different across the people who have it. But a few key themes have emerged.

Researchers believe that autism is most likely the result of a complex set of interactions between genes and the environment that unfold while a child is in the womb. It can be passed down through families, or originate with a spontaneous gene mutation.

Environmental influences may indeed play a role in some autism cases, but their effect is heavily influenced by a person's genes. There is no evidence for a single trigger that causes autism, and certainly not one a child encounters after birth: not a vaccine, a parenting style or a postcircumcision Tylenol.

"The real reason why it's complicated, the more fundamental one, is that there's not a single cause," said Irva Hertz-Picciotto, a professor of public health science and director of the Environmental Health Sciences Center at UC Davis. "It's not a single cause from one person to the next, and not a single cause within any one person."