New noninvasive prenatal test can screen for CF, other genetic diseases
Natera launches Fetal Focus after observational trial shows over 90% accuracy
A new noninvasive prenatal test for cystic fibrosis (CF) and three other inherited conditions, launched by Natera, uses a sample of the mother’s blood to screen fetal DNA.
The test, called Fetal Focus, may be particularly useful when the baby’s biological father isn’t available for genetic testing to confirm potential fetal risk, Natera suggested in a company press release announcing its launch.
“Fetal Focus adds another important offering within our comprehensive reproductive health portfolio – furthering our commitment to launching products that address clinical gaps in care and are supported by rigorous clinical validation,” said Sheetal Parmar, senior vice president of medical affairs for women’s health at Natera.
The product’s launch was based on positive preliminary findings from an observational clinical trial, called EXPAND (NCT06808880), that was sponsored by Natera. It showed that the test correctly identified more than 90% of cases of CF and other genetic conditions before birth.
Fetal Focus screens a baby’s DNA before birth for mutations known to cause recessive single-gene diseases — those caused by mutations in a single gene and where two mutated copies of the gene, one from each biological parent, are needed for the disease to develop.
In CF, mutations in both copies of the CFTR gene cause problems with cellular regulation of salt and water. As a result, the body produces thick, sticky mucus that typically builds up in organs, leading to lung and digestive problems, as well as other symptoms.
Test can help when baby’s father can’t be screened
Individuals with only one mutated copy are carriers of the disease but won’t have CF themselves. Oftentimes, carriers won’t know their status before becoming parents absent genetic testing. Potential or expecting parents may find out they are carriers of CF or another recessive single-gene condition only during genetic counseling.
Having access to a noninvasive option like Fetal Focus can provide critical information to support decision-making during pregnancy, especially in situations where partner testing isn’t possible.
If one parent is a known disease carrier, testing the other parent to see if that individual also has a mutated copy of the gene in question can help predict the child’s risk of developing the condition. However, both parents aren’t always available for genetic testing.
In cases where the mother is the only available parent, clinicians may be able to test the fetus directly. But such testing usually involves invasive measures.
Fetal Focus aims to provide a noninvasive way to test the baby before birth, according to its developer. In addition to CF, the other conditions tested with Fetal Focus are spinal muscular atrophy (SMA), alpha-thalassemia, and beta-hemoglobinopathies such as sickle cell disease.
“Having access to a noninvasive option like Fetal Focus can provide critical information to support decision-making during pregnancy, especially in situations where partner testing isn’t possible,” said John Williams, MD, chief principal investigator for EXPAND and director of reproductive genetics at the Cedars-Sinai Prenatal Diagnosis Center in Los Angeles.
Study enrolled over 1,300 pregnant US women
The test’s launch is supported by initial results from the EXPAND study, being conducted across 20 sites in the U.S. The observational study has so far enrolled about 1,300 pregnant women whose fetuses have a higher risk of single-gene diseases.
Participants include pregnant adults who are carriers of a single-gene condition. Also eligible are women ages 18 and older who are affected by one of these conditions themselves, and those in whom prenatal ultrasound findings suggest that the developing fetus may have a single-gene disorder.
While CF, SMA, alpha-thalassemia, and beta-hemoglobinopathies are the primary focus of the study, pregnant women whose babies are at risk of other single-gene conditions may also participate.
Each participant provides a blood sample, and allows the collection of a cheek swab of their baby within six months of delivery to perform genetic testing and confirm whether the Fetal Focus results were correct.
The study’s first milestone readout, covering data from 101 participants, showed that the new test could correctly identify, before birth, 91% of the babies who were subsequently found to have a single-gene condition, according to Natera.
Fetal Focus also successfully identified 5 of 5 homozygous cases — where a child inherits the same disease-causing mutation from both parents. Homozygous cases are particularly challenging to detect, as their genetic results may resemble those from a fetus who inherited only one mutated copy; only those with two affected genes will develop the condition.
The new test uses Natera’s proprietary LinkedSNP technology to improve detection of homozygous cases across diverse populations, per the developer.
“The EXPAND study has been underway for several years, and we’re pleased to release this first milestone readout,” Parmar said.
EXPAND may still be recruiting, and is expected to end early next year.
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