The biggest indicator of Down syndrome is the presence of an extra copy of chromosome 21. This genetic condition is also known as trisomy 21.
How is Down Syndrome Diagnosed?
While the presence of an extra chromosome is the definitive indicator, Down syndrome is often diagnosed through various prenatal screenings and postnatal tests, such as:
- Prenatal Screening:
- Ultrasound: This imaging technique can detect physical features associated with Down syndrome, like a thickened nuchal fold (a fold of skin at the back of the neck).
- Blood Tests: These tests measure levels of certain proteins in the mother's blood that can indicate an increased risk of Down syndrome.
- Postnatal Tests:
- Karyotype: This test analyzes the chromosomes in a person's cells to confirm the presence of an extra chromosome 21.
Other Signs and Symptoms
While an extra chromosome is the primary indicator, some physical characteristics are commonly associated with Down syndrome, including:
- Upward slanting eyes
- Single deep crease across the palm of the hand
- Small stature
- Delayed development
It's crucial to remember that these features are not always present in individuals with Down syndrome, and their severity can vary.
Note: This information is for general knowledge and does not constitute medical advice. If you have concerns about Down syndrome, consult a healthcare professional.
