Q90.9

Clinical Causes: Presence of an extra copy of chromosome 21 (trisomy 21) in most cases Mosaicism, where some cells have an extra chromosome 21 and others do not Translocation of chromosome 21 parts, involving chromosome 21 and another chromosome

Key Symptoms: Distinct facial features such as flat facial profile, upward-slanting eyes, small ears, and a short neck Poor muscle tone (hypotonia) at birth Growth delays and short stature during childhood Developmental delays in speech, motor skills, and cognitive abilities Potential health issues including heart defects, hearing and vision problems, and thyroid conditions Shorter stature and possible dental issues Increased risk for certain medical conditions, such as leukemia and Alzheimer’s disease

Diagnosis Path: Diagnosis of Down syndrome is often suspected based on physical features observed at birth or during early childhood. Confirmatory tests include: - Chromosomal analysis (karyotyping), which detects the extra chromosome 21 - Fluorescence in situ hybridization (FISH) tests for more rapid detection Genetic counseling and screening are also available during pregnancy to assess the risk of Down syndrome in a fetus.

Treatment Protocols: There is no cure for Down syndrome, but various interventions can help manage symptoms and support development: - Early childhood programs emphasizing speech, motor skills, and cognitive development - Regular medical check-ups to monitor and treat associated health issues - Speech, occupational, and physical therapies tailored to individual needs - Surgical interventions for congenital heart defects or other physical anomalies when necessary - Educational support and specialized learning programs Team-based approaches involving healthcare providers, educators, and family support are essential for optimizing quality of life.