This study characterized clinical, sociodemographic, psychiatric, and gastrointestinal variables in 55 families, comparing children with Autism Spectrum Disorder (ASD) to neurotypical siblings. Primary objectives were to delineate sociodemographic profiles and systemic barriers, establish a clinical-nutritional baseline for Uruguayan children, and generate metadata for future microbiome research. We conducted a cross-sectional, case-control study including children aged 4–10 years and sibling controls. Professionals collected data via clinical interviews. Findings indicate a higher male prevalence in the ASD group. Mothers predominantly participated in caregiving and interviews. In the ASD group, 60% of pregnancies had complications, including 12 twin pregnancies. No significant differences were found regarding parental age, delivery method, prematurity, or birth anthropometry. Head circumference at birth did not associate with regression or severity. All children with ASD showed sensory particularities; 94.3% reported gastrointestinal symptoms. We observed a 20-month diagnostic gap and 65% regression rates between 12–36 months. These data highlight the need for improved early detection and provide essential local evidence for the Uruguayan ASD population. This interdisciplinary approach bridges clinical practice and research, advancing contextualized care in Uruguay.