5. Females with Autism Present Features Differently

Females with autism show opposite neurobiological features of autism, while alsopossessing some of the same core features of ASD. In females, these differences may be foundinthe way symptoms present or in associated features of ASD.Lack of differentiationclouds important scientific discoveries, which is why treatments and services should besex specific.

Over the past five years, ASD research has increasingly focused more attention on identifying and understanding how autism manifests in females; this includes, but is not limited, to: genetic makeup, symptom presentation, long term trajectory and mental health issues. Females are diagnosed 4x less often but also have an increased load of genetic mutations, including recessive mutations⁴⁷. This year, results of studies have been mixed in terms of the magnitude and nature of sex and gender related symptom presentation in males vs. females, noting a problem plaguing ASD research mentioned earlier: heterogeneity⁴⁸. Differences across sex and gender are not seen in terms of presence or absence of symptoms, but rather in the way they present across different ages^49,50. On the whole, differences are few in infants and toddlers but are magnified during adolescence, even in the way people perceive ASD symptoms in males and females⁵¹. Some scientists suggest that associated symptoms are most likely to present differently than core symptoms of ASD⁵², with females showing a higher prevalence of ADHD⁵³and OCD, leading to differences in the way males and females appear. 

In addition to findings of increased numbers of recessive mutations in the genome of females⁴⁷, analysis of brain structure has revealed sex differences further suggestive of the female protective effect. Focused study of the cerebellum has revealed that female activation patterns oppose those of males with ASD ⁵⁴and fail to evince similar patterns of connectivity across different brain regions^55,56, i.e.  females with ASD show reduced connectivity compared to females without ASD, an effect not seen in males with ASD⁵⁵. In addition, when comparing twins, females had more profound differences in the sizes of  brain regions compared to males⁵⁷. These findings have led researchers to refine how they examine the role gender plays in basic science research.  

Animal model research suggests that environmental exposures may not produce the same impairments in male vs. female offspring⁵⁸. Taken together, these biological findings demonstrate that females, despite demonstrating a lower prevalence of ASD, also show complicated behavioral features and more biological markers for ASD. Future research must focus on why females are diagnosed less often than males and why, when they are diagnosed, they present more behavioral markers than their male counterparts.