Q90.2

Clinical Causes: Translocation of chromosome 21: A piece of chromosome 21 becomes attached to another chromosome, often chromosome 14 or 15. Parental translocation: This can be inherited if a parent carries a balanced translocation during reproductive cell formation. Random translocation event: Occasionally, the translocation occurs anew in the egg or sperm cell without being inherited.

Key Symptoms: Distinct facial features: Flat facial profile, upward slanting eyes, small ears, and a flattened nasal bridge. Developmental delays: Mild to moderate intellectual disability and delayed speech and motor skills. Medical issues: Congenital heart defects, hearing and vision problems, and a higher susceptibility to infections. Physical characteristics: Short stature, a single crease across the palm, and muscle hypotonia (poor muscle tone). Other features: Short neck, enlarged tongue, and certain behavioral traits such as increased susceptibility to anxiety.

Diagnosis Path: Diagnosis often involves a chromosomal analysis called karyotyping, which examines the structure and number of chromosomes in a sample of blood or tissue. This testing can reveal the presence of an extra chromosome 21, or in translocation cases, identify the rearranged chromosomes. Prenatal screening methods, such as ultrasound and maternal blood tests, can suggest the possibility of Down syndrome, leading to confirmatory invasive testing if needed.

Treatment Protocols: While there is no cure for trisomy 21, early intervention programs are essential to support development. Management may include speech, occupational, and physical therapies to improve communication, motor skills, and daily functioning. Regular medical checkups are vital to monitor and treat associated health issues, such as heart defects or vision problems. Educational and behavioral support can help individuals with Down syndrome lead healthy, fulfilling lives, with tailored support to their needs.