1. Identify the sex chromosomes: Look for the X and Y chromosomes, which are typically smaller and distinct in shape. In this karyotype, the last pair (23rd pair) should be the sex chromosomes.
2. Count the total number of chromosomes: A normal human has 46 chromosomes (23 pairs). Check if there are exactly 46 chromosomes present.
3. Examine chromosome 21: Look at the 21st pair of chromosomes. In a normal karyotype, there should be two copies. If there are three copies of chromosome 21, it indicates Down Syndrome.
4. Analyze the karyotype: In this case, there are three copies of chromosome 21, which is a clear indication of Down Syndrome.
5. Confirm the diagnosis: Since Down Syndrome is caused by trisomy 21 (three copies of chromosome 21), and this karyotype shows exactly that, the diagnosis is Down Syndrome.
Parent Tip: Review the logic above to help your child master the concept of karyotype lab worksheet answers.
