Genetic disorders of the fetus
Anytime there is a pregnancy, there is a 3% risk of having a child with some defect, mental impairment, or genetic mutation, according to Beaumont Health System.
A fetal genetic test for chromosomal abnormalities in a fetus can provide critically important information. Understanding chromosomal abnormalities and fetus genetic disorders empowers doctors and prospective parents with crucial information.
The key to understanding fetal chromosomal abnormalities and their ramifications begins with high-risk pregnancy specialists who understand genetics. Pregnant women in the Los Angeles area seek the expert counsel of Dr. Steve Rad, a double-board certified Obstetrician-Gynecologist with sub-specialty training in Maternal-Fetal Medicine (MFM).
Dr. Rad, a high-risk OB/GYN, advises expectant mothers to be constantly vigilant about their condition. Low-risk pregnancies can quickly escalate into high-risk births.
Dr. Rad and his team at the Los Angeles Fetal and Maternal Care Center have decades of perinatology experience. They are among the very best high-risk pregnancy specialists in Los Angeles. The team is also available to provide a second opinion on chromosome defects in the fetus.
What is genetic predisposition?
A genetic predisposition (also called genetic susceptibility) is not a disease. Instead, it is a marker that shows a condition the baby could develop based on its genetic makeup. Genetic anomalies (also called gene variants) are passed on from parent to child.
Usually, there must be at least one additional contributing factor beyond predisposition to trigger an abnormality. However, about 7.9 million infants worldwide are born with serious birth defects each year.
Fetal testing for genetic disorders can reveal a predisposition for the disease and potentially lead parents to take preventative measures. Dr. Rad and his high-risk OB team give prospective parents advice on interpreting fetal genetic testing. We can also advise on actual risks and possible actions parents may take.
What are genetic disorders caused by?
Genetic disorders are caused by a baby’s chromosomes or genes malfunctioning. The malfunction causes physical abnormalities or illness.
Each baby has millions of cells with 46 chromosomes (23 from each parent). These chromosomes are an instruction kit for the baby’s physical and mental make-up, from eye color to disease risk.
When there is a change in these instructions, it affects how the baby develops.
Several factors that can indicate a possible problem in the baby’s development include:
- A genetic disorder in the family
- An existing sibling with a genetic disorder
- A parent with a chromosomal mutation
- Mother is 35 or older
- Father is 40 or older
- Mother has a history of miscarriage or stillbirth
- Parents smoke, drink alcohol, or use drugs
- Parents are exposed to a toxic external environment
What are some types of genetic disorders?
There are four principal types of genetic disorders in pregnancy (h3)
Single gene disorders
Chromosomal abnormalities (trisomy)
This happens when there are missing or extra chromosomes or pieces of chromosomes. The most common condition caused by this abnormality is Down syndrome.
These conditions occur when the baby is exposed to toxic substances (teratogens) during pregnancy. In utero exposure to teratogens causes abnormalities. Examples of teratogens include alcohol, drugs, lead, high levels of radiation, certain medicines, and infections.
Testing for genetic diseases
Doctors use two types of tests to identify prenatal genetic disorders:
- Screening tests alert physicians of the presence of an abnormal number of chromosomes in a cell (aneuploidy).
- Diagnostic tests inform whether the fetus has a disorder. This test is performed on cells from the fetus or placenta acquired through amniocentesis or chorionic villus sampling (CVS).
Types of genetic screening tests
The two types of genetic screening tests are carrier and prenatal genetic screening:
1. Carrier screening
Carrier screening can be done before or during pregnancy. This test uses a blood sample or tissue sample swabbed from inside the cheek. The test identifies whether either parent carries the gene for certain inherited disorders.
2. Prenatal genetic screening
Prenatal screening looks at the pregnant woman’s blood test along with results from ultrasound exams. The screening is done during the first trimester between 10 and 13 weeks, and then again during the second trimester.
One such prenatal is the test nuchal translucency test (also called the NT scan). An NT scan is performed between 11-13 weeks when the back of the developing fetus’ neck can be measured. The test can indicate Down syndrome. It also examines physical defects in the heart, abdominal wall, and skeleton. During the second trimester (15 to 22 weeks), doctors again test for Down syndrome, Edwards syndrome, and brain and spine defects.
When to pursue genetic counseling
- Before becoming pregnant. At this time, you may discuss increased risks and apprehensions you may have about:
- Genetic circumstances with you or your partner’s family
- History of miscarriages or stillbirth
- Prenatal diagnosis
- Prenatal screening for your unborn baby
- An earlier pregnancy or child with a birth defect or genetic condition
- Assisted reproduction technology choices
- While pregnant. A genetic counselor can explain tests that may be performed and possible conditions that may affect the baby. These include:
- Abnormal test results
- Maternal infections and exposure to drugs, toxic chemicals, or X-rays
- Genetic screening
- Parents with growing children. A genetic counselor can discuss signs and symptoms that may be genetic, including:
- Abnormal newborn screening results
- Birth defects
- Intellectual or developmental disabilities
- Autism spectrum disorders
- Vision or hearing problems
Treatments for genetic disorders
Though specific to each pregnancy, treatment may include:
- Expert care from a maternal-fetal medicine doctor
- Personal care is based on a genetic disorder
- Fetal intervention or surgery directly after birth
- A collaborative team to treat the fetus and coordinate referrals
More about Dr. Rad
Perinatologist Dr. Rad and his world-class Maternal-Fetal Medicine (MFM) obstetrics and gynecology team at Los Angeles Fetal and Maternal Care understand your High-Risk OB and infertility needs before, during, and after birth. We provide compassionate care and help you understand your pregnancy, answer questions, and provide emotional support to navigate your pregnancy safely.
Dr. Rad has undergone rigorous training with high honors at prestigious, renowned institutions such as the David Geffen School of Medicine at UCLA, USC, Cedars-Sinai Medical Center, and UCSF Medical Center, as well as centers internationally in London, Austria, Israel, and Africa.
Call us at (844) 473-6100 or schedule your consultation online. We are currently accepting new patients.
We are conveniently located for patients throughout Southern California and the Los Angeles area at locations in or near Beverly Hills, Santa Monica, West Los Angeles, West Hollywood, Culver City, Hollywood, Venice, Marina del Rey, Malibu, Manhattan Beach, Newport Beach, Irvine, and Downtown Los Angeles. We also offer in-home prenatal care and a fly-in program for out-of-town and international patients. Dr. Rad even travels to patients who need him throughout the U.S. and around the world.
If you can’t make it to Dr. Rad, he also offers virtual consultations worldwide.