Risk factors and clinical profile of autism spectrum disorder in southern Brazil.

In Brazil, as in other countries, it is expected a significant variation of epidemiological and clinical characteristics among individuals with autism spectrum disorder (ASD). This study was performed to explore maternal risk factors and clinical characteristics of children with ASD in a population located in southern Brazil. Data were collected from medical records and analyzed to explore biomarkers associated with ASD. Out of 321 children with ASD, 86.5% were males with a male-to-female ratio of 5.7:1, 50.7% were mild/moderate while 49.3% presented severe ASD. Between the risk factors investigated, gestational infection was significantly associated with severe ASD patients. There was also an association between epilepsy and severe autism. Several gastrointestinal (GI) symptoms were significantly associated with severe ASD. Obesity, followed by lower levels of cholesterol, were also significant factors associated with an ASD diagnosis when compared to age-matched controls. Finally, severe ASD was associated with significantly higher serum serotonin levels when compared to age-matched controls and mild/moderate ASD cases. Our findings demonstrate that our population shares many features associated with ASD around the world, such as GI symptoms, epilepsy, and high serotonin levels. It is worth highlighting the low cholesterol levels associated with obesity as an unusual feature that deserves more attention.