Ariana Eunjung Cha at WP:
Natalie Sauerwald is one of the lead authors of the subtypes study and a computational biologist at the Flatiron Institute, part of the Simons Foundation, which funds scientific research. She compared earlier autism research to assembling a jigsaw puzzle, only to find that the pieces didn’t quite fit — not because the image was unclear but because “the box had always contained several puzzles, shuffled together.”
There isn’t just one autism, Sauerwald said: “There are many autisms.”
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The work published in July in Nature Genetics detailed the four categories.
- Broadly affected: The smallest group — about 10 percent of participants — faced the steepest challenges, marked by developmental delays, difficulties with communication and social interaction, and repetitive behaviors that touched nearly every part of life.
- Mixed autism with developmental delay: Roughly 19 percent showed early developmental delays but few signs of anxiety, depression or disruptive behavior. Researchers call this group “mixed” because its members vary widely in how strongly they display social or repetitive behaviors.
- Moderate challenges: About a third of participants fell into this group, showing the hallmark traits of autism — social and communication differences and repetitive habits — but in subtler ways and without developmental delays.
- Social and/or behavioral: The largest group, around 37 percent, met early developmental milestones on time yet often grappled with other conditions later on, including ADHD, anxiety, depression or obsessive-compulsive disorder.
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That breakthrough idea was given another boost in October when a second study — published in Nature by an entirely different team using separate data — arrived at essentially the same conclusion: Genetically distinct forms of autism may unfold on different life timelines. The new analysis, based on data from the United States, Europe and Australia, suggested that children diagnosed after age 6 carried distinct genetic profiles and that their form of autism looked strikingly different from the early-childhood type — less like a developmental delay and more akin to conditions such as depression, ADHD or post-traumatic stress disorder.
