Autism spectrum disorder (ASD) is a clinically and etiologically heterogeneous neurodevelopmental disorder characterized by an early lack of social communication and interaction and an unusually limited and repetitive repertoire of behaviors and interests. PSA is associated with a significant lifetime burden of health loss. Despite widespread attention to the marked increase in the reported prevalence of PSA over the past 3 decades, identification and quantification of cases remains complex. Research objective: The research objectives in this final paper were to investigate the probability of chromosomal changes in children with PSA, and to analyze the gender distribution in children with autism and to investigate the influence of the date of birth on the development of autism Respondents and methods: The research was conducted retrospectively in the period from 2019 to 2022. The data used in the research were obtained from the hospital information system of KBC Rijeka, Clinic for Pediatrics. 114 subjects were included in the research. Results: The research used data from a total of 114 children with autism spectrum disorders aged 2.5 to 15 years, with an average age of 5.5 years. At diagnosis, karyotype changes were recorded in 2.44% (2 out of 82 subjects) of children with autism spectrum disorder. By comparative hybridization of the genome on the microarray (aCGH), changes in one of the 7 subjects (14.29%) of the children were proven. 5.56% of children (5 out of 90 subjects) had a positive diagnosis of fragile X syndrome. The average age of diagnosis was 3 years. In the research, male respondents predominated (76.32%). In the study of the influence of the date of birth on autism, data from a total of 110 children were used, whereby the majority of children (92.73%) were born on time. Conclusion: The total average percentage of chromosomal changes, taking into account the different number of processed findings for each parameter, was 4.47%. which is in line with the range between 2% and 15%, as indicated by other studies. The obtained gender distribution does not differ from other research on the same topic. In our sample, a large proportion of children born at term predominate.