02/16/2026
https://www.facebook.com/share/1DeLSuUa5X/?mibextid=wwXIfr
It’s very common for both siblings to be Autistic, but for only one to get a diagnosis early (or ever!) because they present so differently.
While this example includes two very different autism presentations, differences don’t have to be this extreme. However, it is true that usually one sibling is more stereotypically autistic and has higher support needs while the later or underdiagnosed sibling is non stereotypical with lower support needs (and often diagnosed AHDH in my experience, although Autism and ADHD would be more appropriate).