Jordanna Joaquina, MS, CGC  

Interests: Prenatal Genetics, Pediatric Genetics
Los Angeles, CA
All Journal Entries Journals
Previous | Next

What Every Expecting Parent Should Know About Genetic Testing

Oct 26, 2009 - 6 comments

genetic testing








genetic disorders


genetic disease


genetic diseases

So you’re pregnant…time to celebrate!  But how to celebrate when you’re told your pregnancy could be affected by countless disorders, with names you can't even pronounce?

Thankfully, most babies are born healthy.  There are, however, a number of reasons you may want to speak with a genetic counselor (a medical professional trained in assessing the risk for birth defects and genetic disorders) before or during your pregnancy.  Some more common reasons include:

* Maternal age
* A family history of a condition
* Ethnic-based carrier testing

Maternal Age
As women age their eggs age and, consequently, so does their risk of having a child with a chromosomal abnormality.  Down syndrome (also known as Trisomy 21) is the most common chromosomal abnormality and people with Down syndrome have varying degrees of mental retardation and physical birth defects.  A woman’s estimated risk of having a child with Down syndrome is:

* At age 25, 1 in 1,250
* At age 30, 1 in 952
* At age 35, 1 in 385
* At age 40, 1 in 106
* At 45, 1 in 30
* At 49, a 1 in 11

Nevertheless, in 2007 the American College of Obstetrics and Gynecology (ACOG) recommended that all pregnant women, regardless of age, be offered screening for Down syndrome, as well as the option of diagnostic testing.  Diagnostic testing can tell with greater than 99% accuracy whether or not a pregnancy is affected with Down syndrome, Trisomy 18 and other chromosomal abnormalities, as well as certain genetic diseases (if indicated).

For more information on screening and diagnostic testing options during pregnancy, visit:

History of Genetic Disorder (or Conditions Associated with a Genetic Disorder)
Family history is one of the most important tools in assessing the risk for a birth defect and/or genetic disorder.  The risks of having an affected child is condition specific, but may depend on multiple factors such as the inheritance pattern of the disorder, the degree of the relationship of affected family members (i.e., first degree, second degree, etc.) and the gender and number of affected relatives.  

A family history of any of the following conditions (and many more not listed) may warrant seeing a genetic counselor:

* Chromosomal abnormalities (such as Down syndrome, Trisomy 13, etc.
* Muscular dystrophy
* Neurofibromatosis
* Seizures
* Recurrent miscarriages (two or more)
* Fertility problems
* Ashkenazi Jewish disorders (such as Tay-Sachs disease, Canavan disease, etc.)
* Hemophilia and other bleeding disorders
* Cystic fibrosis
* Huntington’s disease
* Mental retardation
* Autism
* Birth defects (such as spina bifida, congenital heart defects, etc.)

To find detailed information on a specific genetic condition, visit: http://www.AccessDNA.com/Genetic_Education_and_Information

Ethnic-Based Carrier Testing
Some genetic disorders, such as sickle cell disease, Tay-Sachs disease, thalassemia and cystic fibrosis, occur more frequently in people of certain ethnic backgrounds. Many of these conditions are inherited in an autosomal recessive pattern, which means two copies of a mutated gene, one from each parent, are necessary to cause the disorder. People with only one copy of a mutated gene are known as carriers. In most autosomal recessive conditions, carriers do not have any symptoms of the condition and, therefore, are often unaware that they are a carrier.

In the absence of a known family history of such disorders, the risk of being a carrier is based on a person’s ethnic background.  The risk of having a child with such disorders is based on the inheritance pattern, as well as both of the parent’s ethnic backgrounds.  As such, couples who are of the same ethnic background may have a higher risk of having a child with autosomal recessive disorders than couples who are of different ethnic backgrounds.  Couples who are related to each other by blood, such as cousins, may have an even higher risk.

Carrier testing is currently available for many autosomal recessive conditions if indicated by ethnic background.  Testing is typically performed on a blood sample, but in some cases, can be performed on cheek cells obtained from a cheek swab or saliva sample.

For more information on patterns of genetic inheritance, visit: http://www.AccessDNA.com/condition/Patterns_of_Inheritance/253

What Happens in a Genetic Counseling Session
A genetic counselor will need to know medical information about you and your family and may begin by constructing a family medical tree, called a pedigree.  This pedigree maps out the relationships between three generations of your relatives and will include information such as pregnancy information, major health conditions, known genetic disorders, age of disease diagnosis, lifestyle factors and ethnicity.

For more information on what happens in a genetic counselor session, visit:

Post a Comment
746512 tn?1388807580
by Tammy2009, Oct 26, 2009

*realized afterwards that this is only based on aminocentosis and not the genetic testing of the parents to see if they are carriers etc*

I am currently taking a medical anthropology course in university and this is part of our current topic.  The major issue that has came up in our class is: how you will use the information after the testing is done.  

What will the family do IF the testing shows there is a genetic abnormallity?  Get into the issues of abortion, adoption etc.  If someone doesn't care about whether a fetus has a disability what is there to gain from going through the testing?  We have read a case about a patient that regrets undertaking the test because she wasn't ever going to terminate the pregnancy and she loves her baby as much as if it didn't have Down syndrome.  She felt like there was pressure from the medical community and family that she was wrong in not terminating the pregancy because the baby was "defective".  

I think that so much effort goes into thinking of the risks and whether one should go through the testing that no thought is placed in what actions will be taken regards the results.  What does the syndrome mean?  How disabled could they be? Are we (the family) able to care for a child like that? What is in the best interest of the baby?

If someone is not going to consent to abortion if there is something wrong, then why put them through all the risks involved?

377493 tn?1356502149
by adgal, Oct 26, 2009
I just underwent amnio 10 weeks ago and I have a slightly different perspective.  I would not have terminated my pregnancy regardless of the outcome.  In fact that had absolutely nothing to do with why I opted to have the testing.  I needed to know for certain.  I needed to be able to prepare mentally and emotionally.  Had I not found out ahead of time and had that time to deal with it and accept it, it would have been incredibly difficult for me to handle.  I did not feel any pressure at all from my Dr.'s and have no regrets about having chosen amnio.  I also felt the relatively minor risk associate with amnio was one I was comfortable with.  

Avatar universal
by Worried0110, Nov 17, 2010
hi ive realized u havent been active for awhile and i cant post anything on the genetics forum so tot i try here...

If you are still around pls replay so i may go through the proper channels pay to get ur professional opinion


Avatar universal
by April162010, Jan 03, 2011
I didnt know" Autistm" is a genetic problem....????

1712052 tn?1312342728
by handsfull611, Jun 19, 2011
I agree with april162010 about Autistm... I have a son who is autistic and I had all the genetic testing and it all came back normal.. I believe it is more environmental.. in the place I lived when I had Ty.. there are many autistic children born there yearly all at different levels on the spectum... and I dont beleive either that the immunization did it... Ty had signs of autism from day one... I am going through genetic testing and no matter what they tell me about this baby i'm carrying .. I have no plans of terminating.. I want to be prepared for when baby is born...and for no other reason and I too have had lots of support on my desision from the medical world... if the world was only as accepting... but our faith in God making no mistake and everyting is for a reason.. who am I to say this precious gift isnt' perfect in every way...even if that baby isnt' "Typical"...

5132983 tn?1364082191
by Magstar32, Mar 24, 2013
My son has just had genetic tests tht have came bk saying he has a duplicate of chromosome 5 q reading at 33.3 to 34 im aware of his promblems ie falling constantly bumping tripping up memory loss anxious about certain things on tv we are awaitin a referel for the occupational theripist n hes not picked much up after 2 years at school its all very distressing for me i cant find anythin on that chromosome duplication and now my self n dad need testing i have A 10 year old daughter who is very bright n dosent show these promblems will she need tested also what are the chances of her kids later in life having a genetic fault i wish i had anwsers to all my thoughts going mad !!!

Post a Comment