Name of the Condition

• Trisomy 21, nonmosaicism (meiotic nondisjunction)
• Commonly known as Down syndrome

Summary

• Trisomy 21, or Down syndrome, is a genetic disorder caused by the presence of an extra full chromosome 21. It results in a range of developmental and intellectual delays and physical traits.

Causes

• The primary cause of Trisomy 21 nonmosaicism is meiotic nondisjunction, where an error in cell division leads to an egg or sperm cell with an extra copy of chromosome 21. This condition is not inherited but occurs as a random event during the formation of reproductive cells.

Risk Factors

• Advanced maternal age is a significant risk factor. Women over the age of 35 have a higher likelihood of giving birth to a child with Down syndrome. Other potential risk factors include having a prior child with Down syndrome and being a carrier of genetic translocations related to the condition.

Symptoms

• Symptoms include characteristic facial features (such as a flat facial profile, almond-shaped eyes, and a protruding tongue), developmental delays, intellectual disability, and possible heart defects. Physical growth delays and hypotonia (reduced muscle tone) are also common.

Diagnosis

• Prenatal screenings and diagnostic tests can detect Down syndrome. These include ultrasounds, blood tests, and more invasive procedures like amniocentesis or chorionic villus sampling (CVS) to confirm the extra chromosome.

Treatment Options

• While there is no cure for Down syndrome, various interventions can enhance development and quality of life. These include early intervention programs, physical therapy, speech therapy, and special education. Medical treatments are also available for associated health issues, like heart defects or hearing problems.

Prognosis and Follow-Up

• Individuals with Down syndrome can lead fulfilling lives with proper support and care. Life expectancy is lower than the general population but has increased significantly with modern medical advances. Regular health check-ups are essential to manage associated medical conditions.

Complications

• Potential complications include congenital heart defects, respiratory and hearing problems, Alzheimer's disease, obesity, and thyroid conditions. Proper management of these health issues is crucial.

Lifestyle & Prevention

• While Down syndrome cannot be prevented, genetic counseling is recommended for those with a family history or other risk factors. A healthy lifestyle and regular medical care can help manage symptoms and enhance quality of life.

When to Seek Professional Help

• Seek medical advice if there are concerns about developmental delays, health problems, or if screening tests suggest the possibility of Down syndrome in a fetus.

Additional Resources

• National Down Syndrome Society (NDSS)
• Down Syndrome International
• Global Down Syndrome Foundation

Tips for Medical Coders

• Verify the diagnosis through proper clinical documentation before coding.
• Ensure the distinction between mosaic and nonmosaic Down syndrome, as the ICD codes differ (Q90.0 for nonmosaicism).
• Be aware of and include any associated conditions or complications in the coding to provide a complete clinical picture.