Posts Tagged ‘Trisomy 13’

March is Trisomy Awareness Month

Monday, March 13th, 2017

chromosomesWhat is trisomy?

Babies with trisomy are born with an extra copy of a specific chromosome in most or all of their cells. This means that they have three copies of this chromosome in each cell rather than the typical number, which is two. Health conditions that may be associated with trisomy include heart defects, vision or hearing problems, and intellectual and developmental disabilities.

Chromosomes are the structures in cells that contain genes. Each person normally has 23 pairs of chromosomes, or 46 in all. An individual inherits one chromosome from the mother’s egg and one from the father’s sperm. When an egg and sperm join together, they normally form a fertilized egg with 46 chromosomes.

Sometimes a mistake in cell division occurs before a woman gets pregnant. A developing egg or sperm ends up with an extra chromosome. When this cell joins with a normal egg or sperm cell, the resulting embryo has 47 chromosomes instead of 46.

Common trisomy conditions

Although trisomy can occur with any chromosome, here are the conditions that are most often associated with an extra chromosome:

  • Trisomy 21 or Down syndrome: Down syndrome is one of the most common birth defects. In the US, about 6,000 babies (or 1 in 700) are born with Down syndrome each year. Most affected individuals have intellectual disabilities within the mild to moderate range. Although health conditions such as heart defects and vision and hearing problems are associated, most of these can be treated, and life expectancy is now about 60 years.
  • Trisomy 18 is also called Edward syndrome: Trisomy 18 occurs in about 1 in 5,000 live births each year. Affected individuals may have heart defects, significant intellectual and developmental delays, and other life-threatening medical problems.
  • Trisomy 13, also known as Patau syndrome: Trisomy 13 occurs in about 1 in 10,000 to 16,000 live births each year worldwide. Individuals with trisomy 13 often have heart defects, brain or spinal cord abnormalities, severe intellectual and developmental disabilities, and multiple physical problems in many parts of the body.

It is important to understand that every individual with a trisomy is unique and not all of them will have the same symptoms. The severity of the condition and the associated problems depend on:

  • Which chromosome is duplicated: An extra copy of certain chromosomes, like chromosome 1, is not compatible with life and the embryo will not develop.
  • How much of the extra chromosome is present: If only part of the chromosome is present, symptoms may be milder. If the complete chromosome is present, the symptoms may be more severe.
  • How many cells have the extra chromosome: If the copy of the extra chromosome is in only a few cells (mosaicism), the symptoms are usually less severe than if all of the cells in the body are affected.

In the past 10 years, the March of Dimes has invested over 15  million dollars into research for chromosomal conditions, including trisomy. And many March of Dimes grantees are studying basic biological processes of development. This important research should improve our understanding of how genes and other factors affect the development of a baby.

Have questions? Text or email us at AskUs@marchofdimes.org.

Trisomy Awareness Month

Friday, March 4th, 2016

chromosomes1Have you ever heard of “trisomy”? Trisomy is a chromosomal condition that is the result of a mistake in cell division. Chromosomes are the structures in cells that contain genes. Each person normally has 23 pairs of chromosomes, or 46 in all. An individual inherits one chromosome from the mother’s egg and one from the father’s sperm. When an egg and sperm join together, they normally form a fertilized egg with 46 chromosomes.

Sometimes something goes wrong before fertilization. A developing egg or sperm cell may divide incorrectly, causing that egg or sperm to have an extra chromosome. When this cell joins with a normal egg or sperm cell, the resulting embryo has 47 chromosomes instead of 46.

Babies with trisomy are born with an extra copy of a specific chromosome in most or all of their cells. This means that they have three copies of this chromosome in each cell rather than the typical number, which is two.

Although trisomy can occur with any chromosome, there are a few conditions that are most often associated with an extra chromosome. They are:

  • Trisomy 21 or Down syndrome: Down syndrome is one of the most common birth defects. In the US, about 6,000 babies (or 1 in 700) are born with Down syndrome each year. Most affected individuals have intellectual disabilities within the mild to moderate range. Although health conditions such as heart defects and vision and hearing problems are associated, most of these can be treated, and life expectancy is now about 60 years
  • Trisomy 18 is also called Edward syndrome. Trisomy 18 occurs in about 1 in 5,000 live births each year. Affected individuals may have heart defects, significant intellectual and developmental delay, and other life-threatening medical problems.
  • Trisomy 13, also known as Patau syndrome, occurs in about 1 in 10,000 to 16,000 live births each year worldwide. Individuals with trisomy 13 often have heart defects, brain or spinal cord abnormalities, severe intellectual and developmental disabilities, and multiple physical problems in many parts of the body.

It is important to understand that every individual with a trisomy is unique and not all of them will have the same symptoms. The problems depend on which chromosome is duplicated and how much of the extra chromosome is present. Health conditions that may be associated with trisomy include heart defects, vision or hearing problems, and intellectual and developmental disabilities.

If your baby or someone in your family has a trisomy, you may want to talk to a genetic counselor. A genetic counselor is a person who is trained to know about genetics, birth defects and other medical problems that run in families. She can help you understand the causes of chromosomal conditions, what kind of testing is available, and your chances of having a baby with these conditions. If you already have a baby with a trisomy, the chances of having another baby with the same condition are usually low.

Have questions? Email us at AskUs@marchofdimes.org.

What is trisomy?

Friday, March 6th, 2015

chromosomes1Trisomy is a condition in which individuals are born with an extra copy of a specific chromosome in most or all of their cells. This means that they have three copies of a given chromosome in each cell rather than the typical number, which is two.

Chromosomes are the structures in cells that contain genes. Each person normally has 23 pairs of chromosomes, or 46 in all. An individual inherits one chromosome from the mother’s egg and one from the father’s sperm. When an egg and sperm join together, they normally form a fertilized egg with 46 chromosomes.

Sometimes something goes wrong before fertilization. A developing egg or sperm cell may divide incorrectly, causing that egg or sperm to have an extra chromosome. When this cell joins with a normal egg or sperm cell, the resulting embryo has 47 chromosomes instead of 46.

There are a variety of health conditions that may be associated with trisomy. Common physical problems for individuals with a trisomy include heart defects, vision or hearing problems, and intellectual and developmental disabilities.

Although trisomy can occur with any chromosome, there are three conditions that are most often associated with an extra chromosome. They are:

  • Trisomy 21 or Down syndrome: Down syndrome is one of the most common birth defects. In the US, about 6,000 babies (or 1 in 700) are born with Down syndrome each year. Most affected individuals have intellectual disabilities within the mild to moderate range. Although health conditions such as heart defects and vision and hearing problems are associated, most of these can be treated, and life expectancy is now about 60 years
  • Trisomy 18 is also called Edward syndrome. Trisomy 18 occurs in about 1 in 5,000 live births each year. Affected individuals may have heart defects, significant intellectual and developmental delay, and other life-threatening medical problems.
  • Trisomy 13, also known as Patau syndrome, occurs in about 1 in 10,000 to 16,000 live births each year worldwide. Individuals with trisomy 13 often have heart defects, brain or spinal cord abnormalities, severe intellectual and developmental disabilities, and multiple physical problems in many parts of the body.

It is important to understand that every individual with a trisomy is unique and not all of them will have the same symptoms. The problems depend on which chromosome is duplicated and how much of the extra chromosome is present.

March of Dimes grantees are studying basic biological processes of development to better understand the process of early cell division and how a trisomy may occur. In the past five years, the March of Dimes has invested $5,274,554 in trisomy research.

Screening for birth defects

Tuesday, September 9th, 2008

At my last prenatal appointment I had a combination of tests done to screen for birth defects such as Down syndrome and Trisomy 13 and 18. I was nervous going, but my husband was with me for support. My visit started with an ultrasound. The doctor rubbed a hand-held device (called a transducer) across my belly. The baby was face up and the doctor needed him/her to turn to the side in order to measure the thickness at the back of the neck (called nuchal translucency).  We waited and waited, but he/she wouldn’t budge. I certainly didn’t mind because I was able to admire the beautiful image on the screen longer.

After several minutes, the doctor finally called for a nurse. She brought me a very sweet orange drink and the doctor said he would be back in less than 10 minutes. I was thinking, “yeah right, this isn’t going to work.” Well, wouldn’t you know it. When he came back and put the transducer on my belly, there it was — the most perfect profile. I guess the baby just needed a little energy. Using the mouse on the ultrasound machine, he was able to measure the back of the neck.

Then I was passed off to the nurse who took a blood sample. I don’t know if this is always the case with maternal blood screening, but she pricked my finger and placed about 5 or 6 drops of blood on a card. The office sent the blood sample to a lab and I would get the results back in about four days. The lab calculated my risk of chromosomal birth defects, using the combined results of my blood test and ultrasound exam.

I received a call a few days later. I was told that based on my age, blood work and ultrasound my risk for Down syndrome was 1 in 1, 610 and my risk for Trisomy 18/13 was 1 in > 10,000. I know that no test can gaurantee the birth of a healthy baby, but I was so relieved. It’s always nice to here reassuring news. Waiting for test results can be so stressful.