Abstract
Rett syndrome (RTT) is a rare genetic neurodevelopmental disorder characterized by intellectual disability and severe functional impairments, placing a significant burden on affected families. This exploratory cross-sectional study evaluated family quality of life (FQoL) in Brazilian families of girls with RTT and examined its relationship with sociodemographic and clinical variables. Seventy Brazilian families participated in the study. Data were collected using sociodemographic and clinical questionnaires, the Pediatric Quality of Life Inventory, and the Beach Center Family Quality of Life Scale, which assesses five domains: family interaction, parenting, emotional well-being, physical and material well-being, and disability-related support. The average FQoL score was 3.68 ± 0.67, below the satisfaction threshold (4.0). Emotional well-being had the lowest score (3.16 ± 0.96), significantly lower than other domains (p < 0.001). Overall FQoL was associated with factors such as family income, access to welfare benefits and private health insurance, parental education and employment status, as well as individual characteristics of the person with RTT, including age, aggressiveness, and school type. Taken together, aggressiveness, attendance at a regular school, and a monthly income exceeding four official Brazilian minimum wages explained 29.8% of the variance in FQoL scores. The findings underscore the multifactorial nature of FQoL in the context of developmental disabilities. Improving FQoL for families of individuals with RTT requires integrated strategies that combine emotional support for caregivers, socioeconomic assistance, inclusive education, and medical and psychological care for individuals with RTT. These approaches have direct implications for public policies and service provision in low- and middle-income countries. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12687-026-00888-6.