IONA® Care is a non-invasive prenatal screening test for pregnant women offering an extended test menu. In addition to screening for Down’s, Edwards’ and Patau’s syndrome (trisomy 21, 18 and 13), IONA® Care screens for sex chromosomal aneuploidies (SCAs) and autosomal aneuploidies (AAs).
As with the IONA® test, fetal sex determination is also provided as an option for singleton and monochorionic twin pregnancies.
IONA® Care is carried out on a simple maternal blood sample, and is available from 10 weeks gestation. Results are typically available within 2-5 working days from sample receipt at Yourgene Genomic Services in Manchester, UK.IONA® Care offers a menu-based approach where pregnant women and their healthcare providers can select whether they would like to screen for SCAs, AAs or both.
What sex chromosome aneuploidies can I screen for and how accurate is the test?
- Turner syndrome (45, X)
IONA® Care is >99.99% accurate when detecting Turner syndrome, with a false positive rate of 0.01%. This means thatfor every 1000 tests that return a high risk result, 999 will be truly affected by Turner syndrome, and only 1 would be a false positive.
People with Turner syndrome are born with only one X chromosome present and fully functional. This is sometimes referred to as a 45,XO or 45,X karyotype. This variation is a random occurrence and is not thought to be linked to maternal age, unlike some conditions such as Down’s syndrome. IONA® Care is a screening test and false positive results can occur.
Turner syndrome is rare, affecting about 1 in 2,000 people.
Information provided by the NHS on Turner syndrome states that females with Turner syndrome have a wide range of clinical features, including some distinctive characteristics such as being shorter than average. The vast majority of people with Turner syndrome are infertile. Turner syndrome cannot be cured, but certain symptoms can be treated or managed.1
- Trisomy X (47, XXX)
IONA® Care is >99.99% accurate when detecting Trisomy X, with a false positive rate of 0.01%. This means that for every 1000 tests that are reported as high risk for Trisomy X, 999 will be truly affected, and only 1 would be a false positive.
Trisomy X is a rare chromosomal disorder that only affects females, and is characterized by the presence of an additional X chromosome. A female usually has two X chromosomes but with trisomy X, the female has 3 copies of chromosome X (XXX). IONA® Care is a screening test and false positive results can occur. Trisomy X is rare, affecting about 1 in every 900- 1,000 live births.
The National Organization for Rare Disorders (NORD) states that the severity of symptoms associated with trisomy X vary greatly between individuals, and about 90% of XXX females with remain undiagnosed throughout their life. Common characteristics include language-based learning difficulties, tall stature and low muscle tone.2
- Klinefelter syndrome (47, XXY)
IONA® Care is >99.99% accurate when detecting Klinefelter syndrome with a false positive rate of 0.01%. This means that for every 1000 tests that are reported as high risk for Klinefelter syndrome, 999 will be truly affected and only 1 would be a false positive.
Klinefelter syndrome is a disorder that only affects males. Klinefelter syndrome occurs when a boy is born with an extra X chromosome (XXY). A male usually has one X and one
Y chromosome but with Klinefelter, the male has 2 copies of chromosome X (XXY). IONA® Care is a screening test and false positive results can occur. Klinefelter’s syndrome is rare, affecting about 1 in every 600 males.
Information provided by the NHS on Klinefelter syndrome states that males with Klinefelter often go undetected into adulthood, and sometimes throughout their life. Commonly seen symptoms include tall stature, incomplete puberty, infertility and behavioural problems such as impulsivity3
- Jacobs syndrome (47, XYY)
IONA® Care has a specificity of >99%. The specificity of a test is its ability to identify an individual who truly does not have a given disorder; in this case Jacobs syndrome. This means that for every 100 tests that are reported as low risk for Jacobs syndrome, 99 will be truly unaffected and only 1 would be a false negative.
Jacobs syndrome is extremely rare. As such the accuracy of IONA® Care when testing for Jacobs syndrome has not been calculated, because no samples with the condition were available in the study dataset. It is expected however that the detection rate will be similar to that for other SCAs; around 99%. There is ongoing post-market surveillance to monitor the accuracy of the test and the statistics will be updated as more information becomes available.
Jacobs syndrome is a rare chromosomal disorder that only affects males. Jacobs syndrome occurs where a boy is born with an extra Y chromosome. A male usually has one X and one Y chromosome but with Jacobs syndrome, the male has 2 copies of chromosome Y (XYY). IONA® Care is a screening test and false positive results can occur. Jacobs syndrome is rare, affecting about 1 in every 1,000 live births.
NORD states that affected individuals are usually very tall, and many experience severe acne during adolescence. There may be challenges with learning difficulties, but these are often mild.4
Click here to view the full clinical validation dataset for IONA® Care
NIPT is a screening test
NIPT is a screening test and cannot be considered diagnostic. This means that although the test is highly accurate, it is still a screening test and requires follow up discussions with the healthcare provider. Further diagnostic testing may be required to confirm any findings.
Results should be discussed with the healthcare provider and considered alongside all other clinical information regarding the pregnancy, including the results of the ultrasound scan. Healthcare providers will discuss the most appropriate next steps with the pregnant woman, taking into account their personal wishes.
Diagnosis of SCAs is performed by karyotyping or other cytogenic methods, which can be carried out during pregnancy by either amniocentesis or chorionic villus sampling (CVS), or alternatively after the birth by taking a blood sample from the baby.
Pregnant women and their families can also opt for no further testing.
How can I get an IONA® Care test?
I am a clinic / healthcare professional | I am a pregnant woman