Posts Tagged ‘genes’

Do you need carrier screening?

Friday, March 10th, 2017

preconception healthRecently the American College of Obstetrics and Gynecology (ACOG) updated their recommendations for carrier screening.

A gene is a part of your body’s cells that stores instructions for the way your body grows and works. Genes come in pairs—you get one of each pair from each parent.

Sometimes the instructions in genes change. This is called a gene change or a mutation. Parents can pass gene changes to their children. Sometimes a gene change can cause a gene to not work correctly. Sometimes it can cause birth defects or other health conditions.

For certain conditions, if you inherit a gene change from just one parent, you have the gene change but not the disease. When this happens, you’re called a carrier. A carrier of a genetic mutation does not have any symptoms of the disease or condition. But, if their partner carries a change in the same gene, then they are at risk to have a baby with the condition.

If you and your partner both carry the gene change for a condition, your baby may get two gene changes (one from each of you) and have the disease. If both you and your partner are carriers (you both have the gene change), there is:

A 1-in-4 chance (25 percent) that your baby can have the disease

A 1-in-4 chance (25 percent) that your baby won’t have the disease and won’t be a carrier

A 1-in-2 chance (50 percent) that your baby won’t have the disease but will be a carrier

Who should get carrier screening?

Carrier screening is simply a blood test. The updated recommendations for carrier screening include:

  • All pregnant women should be offered information about carrier screening. They may then choose to have some screening or none at all.
  • Ideally, carrier screening should be done before pregnancy.
  • If a woman is a carrier for a specific condition, her partner should be offered carrier screening as well.
  • If both parents are found to be carriers of a specific disorder, they should meet with a genetic counselor. This will allow them to better understand the condition, the possible risks to their children, and how other family members may be affected.

What conditions should be tested for?

ACOG now recommends ALL WOMEN be offered carrier screening for the following conditions:

  • Spinal Muscular Atrophy (SMA): SMA is a disease that attacks nerve cells in the spinal cord. These cells communicate with your muscles. As the neurons die, the muscles weaken. This can affect walking, crawling, breathing, swallowing, and head and neck control.
  • Cystic fibrosis (CF): CF is a condition that affects breathing and digestion. It’s caused by very thick mucus that builds up in the body. This thick and sticky mucus builds up in the lungs and digestive system and can cause problems with how you breathe and digest food.
  • Hemoglobinopathies: These are blood conditions that are caused by problems with hemoglobin. Hemoglobin is a protein in the blood that carries oxygen. There are different kinds of hemoglobin in the blood, and there are many kinds of hemoglobin disorders. Some are caused when hemoglobin doesn’t form correctly or when your body doesn’t make enough hemoglobin.

Additional carrier screening should be offered for other conditions based on family history. If you are planning a pregnancy or are pregnant already, make sure you talk to your health care provider about the new guidelines and discuss any questions or concerns you may have.

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

What causes Down syndrome?

Thursday, September 26th, 2013

Down syndrome is caused by extra genetic material from chromosome 21. Chromosomes are the structures in cells that contain the genes.

Each person normally has 23 pairs of chromosomes, or 46 in all. An individual inherits one chromosome per pair 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, sometimes causing an egg or sperm cell to have an extra chromosome number 21. When this cell joins with a normal egg or sperm cell, the resulting embryo has 47 chromosomes instead of 46. Down syndrome is called trisomy 21 because affected individuals have three number 21 chromosomes, instead of two. This type of error in cell division causes about 95 percent of the cases of Down syndrome.

Occasionally, before fertilization, a part of chromosome 21 breaks off during cell division and becomes attached to another chromosome in the egg or sperm cell. The resulting embryo may have what is called translocation Down syndrome. Affected individuals have two normal copies of chromosome 21, plus extra chromosome 21 material attached to another chromosome. This type of error in cell division causes about 3 to 4 percent of the cases of Down syndrome. In some cases, the parent has a rearrangement of chromosome 21, called a balanced translocation, which does not affect his or her health.

About 1 to 2 percent of individuals with Down syndrome have a form called mosaicism. In this form, the error in cell division occurs after fertilization. Affected individuals have some cells with an extra chromosome 21 and others with the normal number.

The risk of Down syndrome increases with the mother’s age. Even though the risk is greater as the mother’s age increases, about 80 percent of babies with Down syndrome are born to women under age 35. This is because younger women have more babies than older women.

To learn more about Down syndrome and the types of health problems someone with Down syndrome might have, read this article.

Supreme Court decision related to gene patenting

Monday, June 17th, 2013

double-helix“The March of Dimes is delighted with [the] unanimous Supreme Court decision in the case Association of Molecular Pathology v. Myriad Genetics, finding that the mere identification of a gene or mutation is insufficient to qualify for a patent,” stated Dr. Jennifer Howse, President of the March of Dimes.

“This decision will allow research to proceed unimpeded on some of the most crucial and vexing questions in medicine, such as the cause of preterm birth, which affects one in every 9 babies born in our nation. Genetic predisposition almost certainly plays a key role in some cases of preterm birth; as we learn more and identify genes potentially implicated in this process, we can be confident that research will advance without being hampered by patent infringement claims.

“This decision is a victory for patients and for research. Having signed onto one of the key amicus curiae briefs in this case, the March of Dimes commends the Justices for producing a sensible, thoughtful decision. This decision sets the groundwork for a system of granting patents for genuine innovation and invention in genetics while protecting the ability of research on genes to advance.”

Happy Thanksgiving

Thursday, November 22nd, 2012

Dr. Fisk GreenToday’s guest post is written by Ridgely Fisk Green, PhD, MMSc. Dr. Fisk Green is Carter Consulting contractor at CDC’s National Center on Birth Defects and Developmental Disabilities. Dr. Fisk Green works on improving children’s health through better use of family health history information.

Today, when you end up sitting next to Aunt Irma who likes to talk about everyone’s health problems, don’t tune her out! Take the opportunity to learn more about your family’s health history.

Thanksgiving is a wonderful time to enjoy delicious food and get together with family. You share more than just special occasions with your family—you share genes, behaviors, culture, and environment. Family health history accounts for all of these. Your mother’s genes may have contributed to her type 2 diabetes and you may share some of those genes, but the fact that she never exercises and eats fast food every day also influences her health, and you might share some of those habits, as well.

Family health history information can also be important for keeping your child healthy. Family health history can help your child’s doctor make a diagnosis if your child shows signs of a disorder. It can show whether your child has an increased risk for a disease. If so, the doctor might suggest screening tests. Many genetic disorders first become obvious in childhood, and knowing about a history of a genetic condition can help find and treat the condition early.

Family health history is also very important if you’re pregnant or thinking of having a baby. Remember to collect family health history information from the baby’s father, too. Family health history can tell if you have a higher risk of having a child with a birth defect or genetic disorder, like sickle cell disease. Talk to your doctor if you have any concerns about your family health history or the father’s family health history.

Tips for Collecting Family Health History for Your Child

•Record the names of your child’s close relatives from both sides of the family: parents, siblings, grandparents, aunts, uncles, nieces, and nephews. For genetic conditions such as cystic fibrosis and sickle cell disease, include more distant relatives. Include conditions each relative has or had and at what age the conditions were first diagnosed.
•Use the US Surgeon General’s online tool for collecting family health histories, called “My Family Health Portrait.”
•Discuss family health history concerns with your child’s doctor. If you’re pregnant or planning to get pregnant, share family health history information with your doctor.
•Update your child’s family health history regularly and share new information with your child’s doctor.
•The best way to learn about your family health history is to ask questions. Talk at family gatherings and record your family’s health information—it could make a difference in your child’s life.

Click on this link to learn about family health history from the CDC.

Congenital heart defects

Friday, December 18th, 2009

There have been some painful posts and resulting discussion this week on congenital heart defects (CHD) on Twitter. So I thought it would be a good idea to provide some background information about these conditions and what the March of Dimes is doing to help.

About 35,000 infants (1 out of every 125) are born with heart defects each year in the United States. The term congenital heart defect is a general term used to describe many types of rare heart disorders. The term congenital heart defect is not a diagnosis in itself. Some of the most common heart defects include: patent ductus arteriosus (PDA), septal defects, coarctation of the aorta, heart valve abnormalities, tetralogy of fallot, transposition of the great arteries, and hypoplastic left heart syndrome. Click here to learn more.

Over the past ten years, the March of Dimes has invested over $36 million in heart related research, including CHDs.  A number of scientists funded by the March of Dimes are studying genes that may underlie specific heart defects. The goal of this research is to better understand the causes of congenital heart defects, in order to develop ways to prevent them. Grantees also are looking at how environmental factors (such as a form of vitamin A called retinoic acid) may contribute to congenital heart defects. One grantee is seeking to understand why some babies with serious heart defects develop brain injuries, in order to learn how to prevent and treat them.

If you have questions or concerns about a specific birth defect, please drop us a note at AskUs@marchofdimes.org and we’ll gladly provide you with information.