Autistic individuals may have symptoms that do not contribute to the official diagnosis, but that can affect the individual or the family.

Some individuals with ASD show unusual or notable abilities, ranging from splinter skills (such as the memorization of trivia) to rare talents in mathematics, music or artistic reproduction, which in exceptional cases are considered a part of the savant syndrome. One study describes how some individuals with ASD show superior skills in perception and attention, relative to the general population. Sensory abnormalities are found in over 90% of autistic people, and are considered core features by some.
More generally, autistic people tend to show a 'spiky skills profile', with strong abilities in some areas contrasting with much weaker abilities in others.
Differences between the previously recognized disorders under the autism spectrum are greater for under-responsivity (for example, walking into things) than for over-responsivity (for example, distress from loud noises) or for sensation seeking (for example, rhythmic movements). An estimated 60–80% of autistic people have motor signs that include poor muscle tone, poor motor planning, and toe walking; deficits in motor coordination are pervasive across ASD and are greater in autism proper.
Pathological demand avoidance can occur. People with this set of autistic symptoms are more likely to refuse to do what is asked or expected of them, even to activities they enjoy.
Unusual or atypical eating behavior occurs in about three-quarters of children with ASD, to the extent that it was formerly a diagnostic indicator. Selectivity is the most common problem, although eating rituals and food refusal also occur.
There is tentative evidence that gender dysphoria occurs more frequently in autistic people (see Autism and LGBT identities). As well as that, a 2021 anonymized online survey of 16–90 year-olds revealed that autistic males are more likely to identify as bisexual, while autistic females are more likely to identify as homosexual.