Neurodegenerative Biomarkers in Populations with Intellectual Disabilities: Diagnostic and Therapeutic Capacities

Populations with intellectual disabilities, especially individuals with genetic syndromes such as Down syndrome, are at very high risk of developing neurodegenerative diseases. This article aims to systematically review the capacities and limitations of biomarkers in the diagnosis and treatment of these diseases in these vulnerable populations. A narrative review was conducted using a systematic search of PubMed, Scopus, and Web of Science for studies published between 2000 and 2025 on biomarkers in intellectual disability and neurodegenerative diseases. Peer-reviewed articles in English or Persian were included, and the extracted data were synthesized thematically. Findings show that various biomarkers, including protein biomarkers (such as Aβ and tau), imaging (such as PET and MRI), genetic biomarkers, and fluid-based (blood and CSF) biomarkers, have significant potential in early diagnosis, monitoring disease progression, and evaluating treatment response. However, the use of these biomarkers in the population with intellectual disabilities faces unique challenges, including inherent biological heterogeneity, the presence of comorbidities, methodological barriers in assessment, and complex ethical considerations. The final conclusion indicates that achieving the maximum potential of these biomarkers requires the development of standardized and validated protocols for this specific population, conducting further longitudinal studies, and seriously considering ethical issues. This review emphasizes the importance of international collaborations and multidisciplinary approaches for transforming clinical care for these individuals.