When can a child be tested for possible genetic conditions?
Wondering when (or if) your child should be tested for genetic conditions? From newborn screening to signs that emerge later in development, we walk you through the timelines and testing options.
If you have a family history of a condition that could be genetic, it’s normal to worry that this might be passed on to your baby. But when testing is done early enough, you can have answers and early medical intervention, if needed.
When is it necessary to test a baby for genetic conditions?
“Genetic testing in babies may be recommended when there are certain warning signs that suggest a possible inherited condition,” says Johannesburg-based paediatrician Dr Rowan Goldstein, adding that these could include:
• A family history of a known genetic disorder
• Physical features or developmental concerns noticed at birth
• Health problems in the newborn that aren’t easily explained
• A previous child in the family with a genetic condition
“In some cases, testing may also be offered before birth (during pregnancy) if there are risk factors or abnormal findings on scans. While not all babies need genetic testing, it can be a valuable tool to help diagnose conditions early, giving children the best chance at appropriate care and support,” says Dr Goldstein.
What types of genetic testing are available to new parents?
There are different types of genetic testing available, depending on the reason for testing, says Dr Goldstein. These can include:
• Newborn screening: “In South Africa, many private healthcare providers offer newborn screening in the first few days after birth. This typically involves a heel prick blood sample to screen for certain metabolic or genetic conditions like congenital hypothyroidism or phenylketonuria (PKU). It’s usually done between 24 and 72 hours after birth.”
• Diagnostic genetic testing: “If a baby shows signs of a specific condition (such as unusual facial features, feeding difficulties or delayed development), more targeted genetic tests may be done. These can include blood tests, chromosomal studies or even more advanced DNA sequencing.”
• Carrier testing: “Sometimes parents may choose to be tested themselves to see if they carry genes for certain inherited conditions (like cystic fibrosis or Tay-Sachs disease), particularly if there's a known family history or concern during pregnancy.”
What can parents expect during these tests?
If you’re worried that these tests may be painful for your baby, you’d be relieved to know that most genetic tests in babies are quick to perform and minimally invasive.
Dr Goldstein talks about what they may involve:
• Newborn screening is done with a simple heel prick – just a few drops of blood are collected on a special card.
• Blood tests for more detailed genetic studies are taken from a vein in the baby’s arm or sometimes from the heel or finger. These are similar to routine blood tests and are generally well-tolerated by babies.
• In some cases, saliva swabs or cheek cells may also be used for genetic analysis, particularly for older babies or children.
Once the sample is collected, it is sent to a specialised laboratory for analysis, says Dr Goldstein. “Results may take anywhere from a few days to several weeks, depending on the complexity of the test. Your paediatrician or genetic specialist will guide you through the process and help interpret the results, discussing any next steps or treatment options if needed,” he adds.
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