Scientists: Autism diagnosed at different ages has different genetic profiles

According to scientists, the genetic profile of children with late-diagnosed autism correlates with that of ADHD and mental disorders such as depression and PTSD. In contrast, patients with early-diagnosed ASD are more likely to exhibit reduced social and communication skills, but the correlation with ADHD and mental disorders remains low.

The genetic factors determining the early and late forms were found to be only partially overlapping: their correlation is estimated at approximately 38%. This indicates that the general term "autism" conceals different biological mechanisms. The age of diagnosis is influenced not only by hereditary factors but also by sociodemographic factors, but their contribution was insignificant—less than 15%.

According to the researchers, the differences identified demonstrate that the mechanisms underlying autism may be heterogeneous and depend on the balance of rare and common genetic changes. This, in turn, influences diagnostic approaches: for early cases, extensive genetic screening may be key, while for later cases, comprehensive models that consider polygenic factors, learning characteristics, social environment, and psychoemotional development may be crucial.

Another finding of the study was confirmation that access to specialized care plays a decisive role in determining when a patient is diagnosed. The availability of infrastructure for early testing and family support is directly linked to the ability to adjust a child's developmental trajectory at the earliest stages. The researchers emphasize that understanding a patient's genetic profile will not only help refine the prognosis but also reduce the risk of comorbidities, such as anxiety disorders and depression, which often accompany ASD.

The study also raises the question of personalized treatment: for patients with significant genetic mutations, early corrective therapy and specialist monitoring may be key. For those whose risk factors are distributed polygenetically, a flexible strategy that takes into account the influence of the environment and social interactions is required.

The scientists emphasize that the study's results strengthen the case for developing genomic initiatives at the international level. Integrating genetic analysis into healthcare will not only improve the quality of diagnostics but also enable the development of long-term support programs for patients with ASD. This is especially relevant given the rising incidence of the disease: according to the World Health Organization, approximately 1 in 100 children worldwide is currently diagnosed with autism, and this figure is expected to increase.

Previously, researchers from Stanford University concluded that genes that provide humans with unique cognitive abilities and speech development are associated with an increased risk of autism spectrum disorders. The scientists found that in humans, the most abundant neurons in the outer layers of the cortex (L2/3 IT) evolved significantly faster than expected. It was in these neurons that a sharp decrease in the activity of genes associated with autism occurred. This mechanism could have allowed for longer brain development in childhood and contributed to the development of complex cognitive functions, but these same changes simultaneously increased the risk of neurodevelopmental disorders.