**Background:** Down syndrome (DS), first described in 1866, is the most common chromosomal abnormality in humans, caused by an extra copy of chromosome 21 (trisomy 21). It manifests in three types: trisomy 21 (majority), translocation, and mosaicism. Incidence ranges from 1 in 319 to 1 in 1000 live births, with over 200,000 cases annually globally, and increases with advanced maternal age. Individuals with DS exhibit mild to moderate intellectual disability, characteristic facial features (e.g., brachycephaly, flat nasal bridge, epicanthal folds, Brushfield spots), and a high burden of comorbidities including hearing loss (75%), obstructive sleep apnea (50–79%), otitis media (50–70%), eye issues (60%) such as cataracts (15%) and refractive errors (50%), congenital heart defects (40–50%), neurological dysfunction (1–13%), gastrointestinal atresias (12%), hip dislocation (6%), and thyroid disorders (4–18%). Cognitive impairment ranges from mild (IQ 50–70) to moderate (IQ 35–50) to severe (IQ 20–35). This review aims to comprehensively analyze neurodevelopmental and cognitive features, comorbidities, current diagnostic and management approaches, and the potential role of artificial intelligence (AI) and machine learning (ML) in enhancing DS care.
**Methods:** This is a narrative review that synthesizes existing literature on DS, focusing on neurodevelopmental and cognitive profiles, comorbidities, diagnostics (including prenatal and AI-based methods), and management. The review does not describe a specific systematic search strategy or inclusion/exclusion criteria but draws on a broad range of cited studies. It discusses AI/ML applications in DS diagnosis, including facial recognition, genetic screening, medical data analysis, prenatal support, and decision support systems. The review also references specific studies: one using ML on clinical records of 106 DS subjects to identify features associated with intellectual disability (random forest and gradient boosting models); another addressing executive function decline in 188 adults with DS; and a study using a Logic Learning Machine to predict obstructive sleep apnea (OSA) in DS, with a cross-validated negative predictive value of 73% for mild OSA and 90% for moderate or severe OSA.
**Key Results:** The review reports that first-trimester screening achieves a detection rate for DS of 82–87%, second-trimester screening 80%, and integrated screening approximately 95%. Prenatal diagnostics include nuchal translucency ultrasonography, maternal serum markers (hCG, PAPP-A, AFP, inhibin), and cell-free DNA screening. AI/ML methods can analyze facial images to identify DS-associated features (e.g., upward-slanting eyes, flattened face, small nose), analyze genetic data to detect risk, and process medical records to find patterns. Comorbidities are detailed: congenital heart defects (especially atrioventricular septal defect 45%, ventricular septal defect 20–30%), epilepsy (prevalence 8.1–26% vs. 1.5–5% in general population), dementia (high prevalence in DS adults over 65, with increased risk of Alzheimer disease), autism spectrum disorder (42% prevalence in one cohort), and attention deficit hyperactivity disorder (34% prevalence). A large cohort study (n=1242) found a 28% incidence of pulmonary hypertension in DS patients with comorbidities like OSA. The review emphasizes that cognitive profiles vary, with strengths in visuospatial short-term memory and associative learning, but deficits in verbal short-term memory, explicit memory, morphosyntax, and executive functions (attention, inhibition, processing speed).
**Clinical Implications:** The review underscores the importance of early diagnosis and intervention, including first- and second-trimester screening, multidisciplinary early childhood intervention programs, and individualized education plans (IEPs). AI/ML tools can enhance diagnostic accuracy, reduce false positives, and enable personalized risk assessment and counseling. For example, ML-based predictive models for OSA can improve sleep-related healthcare. However, the review highlights challenges: data quality, interpretability, ethical considerations (privacy, bias), and the need for validation by medical professionals. The authors call for ongoing research to refine AI methodologies and ethical frameworks, and for collaboration among researchers, clinicians, policymakers, and the DS community to maximize benefits. Ultimately, the goal is to leverage AI to improve diagnostic accuracy, intervention strategies, and therapeutic advancements, thereby enhancing the quality of life and autonomy for individuals with DS.