Understanding Down Syndrome
Down syndrome, also called trisomy 21, is one of the most common genetic differences seen in people. It happens when a person has an extra copy of chromosome 21. Let’s talk about what this means and why it’s important for families talking to genetic counselors.
Types of Chromosomal Differences:
Trisomy 21: This is the most common type of Down syndrome, making up about 95% of cases. Normally, people have two copies of chromosome 21. But with Down syndrome, there are three copies. This extra genetic material can affect how a person develops, leading to different traits linked to the condition.
Mosaic Down Syndrome: This type happens in about 1-2% of cases. People with mosaic Down syndrome have some cells with the extra chromosome 21 and some with just the usual two copies. Because not all the cells are affected, the traits may be less severe.
Translocation Down Syndrome: This is a less common type, accounting for about 3-4% of Down syndrome cases. In this situation, part of chromosome 21 attaches to another chromosome. This can cause similar effects as having an extra chromosome 21. Sometimes, this type can run in families, so knowing your family history is important.
Why Genetic Counseling Matters:
When families are learning about Down syndrome, genetic counseling helps them understand the different risks and types of chromosomal differences. This information is especially important for parents who could be at a higher risk, like older mothers.
Risk Factors for Trisomy 21: One big factor is the mother’s age. Women over 35 may have a higher chance of having a baby with Down syndrome. For example, the chance goes from about 1 in 270 at age 35 to about 1 in 100 by age 40.
Testing Options: For families who have concerns, genetic counseling can include talking about different tests that can be done before the baby is born, such as:
Wrapping Up:
Learning about Down syndrome is not just about the scientific facts; it also affects families in very personal ways. Genetic counseling provides families with the information and support they need as they navigate this journey. It helps them understand the risks and realities of Down syndrome and how it may influence their lives.
Understanding Down Syndrome
Down syndrome, also called trisomy 21, is one of the most common genetic differences seen in people. It happens when a person has an extra copy of chromosome 21. Let’s talk about what this means and why it’s important for families talking to genetic counselors.
Types of Chromosomal Differences:
Trisomy 21: This is the most common type of Down syndrome, making up about 95% of cases. Normally, people have two copies of chromosome 21. But with Down syndrome, there are three copies. This extra genetic material can affect how a person develops, leading to different traits linked to the condition.
Mosaic Down Syndrome: This type happens in about 1-2% of cases. People with mosaic Down syndrome have some cells with the extra chromosome 21 and some with just the usual two copies. Because not all the cells are affected, the traits may be less severe.
Translocation Down Syndrome: This is a less common type, accounting for about 3-4% of Down syndrome cases. In this situation, part of chromosome 21 attaches to another chromosome. This can cause similar effects as having an extra chromosome 21. Sometimes, this type can run in families, so knowing your family history is important.
Why Genetic Counseling Matters:
When families are learning about Down syndrome, genetic counseling helps them understand the different risks and types of chromosomal differences. This information is especially important for parents who could be at a higher risk, like older mothers.
Risk Factors for Trisomy 21: One big factor is the mother’s age. Women over 35 may have a higher chance of having a baby with Down syndrome. For example, the chance goes from about 1 in 270 at age 35 to about 1 in 100 by age 40.
Testing Options: For families who have concerns, genetic counseling can include talking about different tests that can be done before the baby is born, such as:
Wrapping Up:
Learning about Down syndrome is not just about the scientific facts; it also affects families in very personal ways. Genetic counseling provides families with the information and support they need as they navigate this journey. It helps them understand the risks and realities of Down syndrome and how it may influence their lives.