Genetic Tests for Newborn Babies

Newborn screening is recommended and sometimes mandated as a means of discovering potential genetic risks in newborns. At DNAGeek, we strive to keep you fully informed of all genomic matters, so you can make educated decisions about your health and your future.

Quick Overview

Within a few days after a baby is born, they undergo several screenings that test for any abnormalities. Hearing and heart screenings make sure that your little one can hear properly and has no congenital defects.

Blood tests are a little more involved, when it comes to the disorders that they screen for. The doctor will prick your baby’s heel and collect a few drops of blood to send off to a lab to evaluate.

The lab typically uses tandem mass spectrometry to evaluate the baby’s blood, a process that separates compounds and fragments into subunits. The screening results are typically available within 5 to 7 days and sent to your pediatrician.

Since each state varies in what they mandate testing for, the results you get may vary depending on where you live. However, according to the March of Dimes, they recommend that newborns get tested for at least 34 disorders, broken down into different categories including:

  • Metabolic
  • Hemoglobin
  • Endocrine
  • Adrenal gland
  • Others – includes several unrelated disorders

Early detection can help reduce the chances of disability or in some cases, death. Early diagnosis can also help treat some disorders and diseases before they become life-threatening.

What Are Genetic Tests for Newborn Babies?

Genetic tests for newborns are designed to scan for specific disorders that can pose a potential hazard to the long-term health of the baby. Most of the disorders they test for within the first two days of an infant’s life can be effectively treated when caught early, which is why it’s so important to have them done.

Some of the disorders are inherited, meaning they’re passed down from parent to child. However, if your child appears to be a carrier for a heritable disorder, it doesn’t necessarily mean they will develop it.

If your little one appears to have specific markers, your pediatrician will want to do further testing and sometimes bring in the help of a genetic counselor. The counselor can explain to you the potential health implications that may occur during your child’s life.

They can also direct you towards more specialized testing and medical professionals who can provide the proper treatment.

Most Common Types of Genetic Tests Done On Newborns

There are a list of 34 genetic conditions that your newborn may be screened for. While not all states have the same number of mandatory genetic tests, they often recommend the following:

  • Phenylketonuria
  • Cystic fibrosis
  • Sickle cell disease
  • Congenital toxoplasmosis
  • Congenital hypothyroidism
  • Galactosemia
  • Homocystinuria
  • MSUD
  • Congenital adrenal hyperplasia
  • MCAD

These are the most common tests, though there are other conditions that might be worth testing for, even if your state doesn’t mandate it. This is especially true if you have a family history of specific genetic conditions such as metabolic or chromosomal abnormalities.

Babies who may appear to have chromosomal abnormalities will need further testing if they were not diagnosed in utero. This includes Down’s, Edward’s, Wolf-Hirschhorn or Patau syndromes. It’s worth noting that not all of these are heritable; many times they’re one-off occurrences.

Genetic Diseases to Screen For

There is a myriad of diseases that newborn screenings test for. Each one has unique characteristics that affect different aspects of an infant’s life.


Babies born with phenylketonuria, also commonly referred to as PKU, lack the ability to process phenylalanine, an essential amino acid. The amino acid accumulates and can cause damage to the brain, including mental retardation.

If your baby is diagnosed with PKU, they will be on a special low-phenylalanine diet during their developing years. Females will need to adhere to this diet during pregnancy as well.

Cystic Fibrosis

One of the more common inherited disorders, cystic fibrosis affects the lungs and digestive system. It can lead to chronic infections and a shorter lifespan of 30 to 35 years.

High-calorie diets and vitamins are often the recommended course of treatment as are specific medications to help patients fight off infection.

Sickle Cell Disease

Sickle cell disease can affect almost anyone, but those of African-American descent are at a much higher risk. If left untreated, the disease can cause strokes, damage internal organs or even potentially kill children, so it’s important to test for it and detect it as soon as possible.

Treatment is diligent and involves antibiotics as well as potentially regular blood transfusions and occasional pain medications as the child grows.

Congenital Toxoplasmosis

Congenital toxoplasmosis comes from a protozoan parasite that’s transmitted from the mother to a child. While it can lead to miscarriages and stillbirth, a baby born with the disease may not present symptoms until years later.

Some exhibit symptoms within 6 months and they can include jaundice, vision problems, hearing loss and developmental delays. Without treatment, progressive problems in cognitive and motor function are likely to occur.

Congenital Hypothyroidism

An infant who is found to have congenital hypothyroidism has a hormone deficiency that can severely affect brain development and growth. This is a treatable condition, though, especially when caught early. The baby will simply get oral doses of the thyroid hormone and it will not have lasting effects.


Infants born with galactosemia lack a specific liver enzyme that’s needed to convert galactose to glucose. An overaccumulation of galactose can cause several health repercussions including mental retardation, blindness, damage to vital organs, severe infections and even death.

Even with the proper treatment, which involves eliminating milk products from the affected person’s diet entirely for life, there may still be developmental delays.


Homocystinuria is a disorder where the body cannot convert homocysteine, an amino acid, into cystathionine which promotes normal brain development. Without detection or proper treatment, it can lead to skeletal abnormalities, strokes, eye problems and potentially mental retardation.

Doctors will prescribe a special diet that incorporates vitamins and supplements such as B6, B12 and betaine.

Maple Syrup Urine Disease (MSUD)

MSUD is named after the fact that the urine smells like maple syrup. Despite its sweet indication, this metabolic disease is actually quite serious and can result in death within a month after birth if it’s not treated.

The diagnosis ranges on a mild to severe spectrum and the disorder can lead to neurological problems. Dietary treatment is necessary with most being prescribed a consistently monitored low-protein diet and possibly the addition of thiamin.

Congenital Adrenal Hyperplasia

This condition, commonly referred to as CAH, is a name for a group of inherited disorders that result in deficiencies of the hormones produced by the adrenal gland. It can potentially be life-threatening if it leads to salt loss in the body.

To treat it, doctors will administer hormone and salt replacement therapies.


MCAD is short for medium-chain acyl-CoA dehydrogenase deficiency. An infant born with this condition lacks the ability to break down fats.

This is an inherited disorder that can lead to difficulty breathing, seizures, coma and other health problems if it’s not diagnosed or treated. The symptoms may not present until adulthood, and often only come on after long periods without eating.

Diet and lifestyle changes are the only prescribed treatments to keep the disease in line.

Why Do Newborn Babies Undergo Screening Tests?

Undergoing screening tests is beneficial for several reasons. First, it helps identify potential disorders and diseases that aren’t visible to the naked eye.

Secondly, testing within the first few days lets doctors discover if there are any diseases present that aren’t showing symptoms yet. The early detection and diagnosis make it easy to start treatment as soon as possible before any real damage is done to a baby’s hearing, vision, nervous system or kidneys.

Additionally, if the mother is suspected to have HIV or Hepatitis B, or tested positive for it while pregnant, the baby will automatically be tested so treatment can begin right away, if necessary.

Are Genetic Tests for Newborns Mandatory?

The answer to this depends on the state that you live in. Some states have mandatory testing requirements, but parents can always choose to opt out. You can have the testing done at a later date or you can choose not to do it at all.

Some parents choose not to undergo newborn screening programs because of religious reasons, while others opt out for personal reasons.

Genetic Tests for Newborns Pros and Cons

As with all types of genetic testing, there are a few pros and cons of having your newborn screened. The good thing about having the testing done is that you’ll be able to identify if there are genetic conditions or diseases that need treatment quickly.

Doctors can begin treatment immediately upon confirmation to reduce the overall risk of complications.

The cons come in when you receive a result that’s a false positive. This can cause excess worry and nervousness, and sometimes when under duress, it’s possible to make split-second decisions without awaiting further testing.

Sometimes an unnecessary treatment is prescribed because of a false-positive result and that can lead to complications.

Additionally, it can be devastating to find out that your child is a potential carrier for specific genetic disorders, but as a parent, it’s important to know that being a carrier or being at a higher risk for these disorders is not a confirmation that they have the disorder or disease. It’s simply a precautionary tale that warrants a further look.

Who Performs Newborn Genetic Tests?

Newborn genetic tests are performed in the hospital by medical professionals, including the doctors and nurses on staff, in the maternity ward. If your newborn needs further testing, and some states do recommend re-testing two weeks after the initial screening, your pediatrician will take the blood sample in the doctor’s office at one of your normal checkups.

How Soon Can a Newborn Be Tested?

It is recommended that you wait at least 24 hours before testing a newborn. The reason for this is that certain disorders, namely congenital hypothyroidism (CH) and phenylketonuria (PKU), may not show up within these few hours after birth.

More accurate representations of whether the disorder is present occur within the 24 to 48 hour post-natal time period.

Covering the Costs of Genetic Tests

Since the genetic tests are done in the hospital as part of the newborn screening program, your medical insurance is likely to cover the testing costs. However, if you do not have insurance you will be required to pay out of pocket.

The good news is that there are medical assistance programs that help to cover not only the costs of pregnancy and delivery but also the costs of medical care for the first year of an infant’s life.

How to Know if Genetic Testing is Right For Your Newborn Baby

Every family has their own personal belief system, including whether or not they decide to have their newborn undergo genetic testing. Only you can make this decision for your little one, but if there are increased risk factors, such as you or your partner being carriers of specific genes and markers, you might want to err on the side of caution and have the tests completed.

If there is no family history of any type of genetic conditions, you can choose to skip the genetic testing altogether.

Are There At-Home Genetic Tests For Newborns?

If you’re wanting to do at-home DNA testing on your newborn, you can certainly do so. There are a few companies who offer the at-home kits, such as Sema4 and 23andMe.

While 23andMe offers the standard DNA ancestry or ancestry + health tests, Sema4 has a kit called Natalis, which is designed specifically for babies.

Natalis purports to analyze your infant’s DNA for over 190 conditions as well as their response to over 40 medications to help create a personalized treatment plan should your baby get sick. The test only requires a buccal swab from the inside of the cheek so there’s no need to prick your infant’s heel.

While the test is designed to be helpful, it is on the more expensive side, costing $379 as of March 2019. Your insurance will not cover this unless it is carried out by a pediatrician in a checkup, and even then there may be issues with coverage.

Most of the time insurance companies won’t pay for any other testing outside of the standard newborn screening if it’s not medically necessary. This means you’ll bear the cost of the test out of pocket.

Additionally, should the test come back with a positive result for a specific marker and you decide you want more in-depth testing, your insurance company is not likely to cover the costs because the testing wasn’t brought on by symptoms but mere curiosity.

Furthermore, direct-to-consumer testing results can be held against your infant decades into the future when they attempt to get life insurance should any markers test positive, so it’s definitely a buyer-beware situation.

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