UNITY Screen™ NIPT for Turner Syndrome (Monosomy X)

Turner syndrome, also known as Monosomy X, is a genetic condition that typically affects females. It occurs when a female is missing all or some of an X chromosome. Turner syndrome prenatal screening through UNITY Screen™ can help expecting parents understand if their baby is at high-risk for this condition at 10+ weeks into pregnancy.

Incidence at Birth

Monosomy X occurs in 1 in 5,000 female births.

Common Names

Monosomy X is another name for Turner syndrome.

Causes

This condition is caused by a female missing one copy of their X chromosome (45,X).

What Is UNITY Screen™ for Turner Syndrome?

UNITY Screen™ is a type of non-invasive prenatal testing (NIPT) that can detect the risk of a developing baby having Turner syndrome as early as 10 weeks into pregnancy. The test analyzes the DNA of the placenta, which is found in the mother's blood draw during pregnancy. UNITY Screen™ can be performed in the first trimester, provides accurate results, and is a noninvasive prenatal screening option, which are important factors many expectant parents consider when comparing Turner syndrome testing options.

How UNITY for Turner Syndrome Works?

What Is Turner Syndrome?

Turner syndrome, or Monosomy X, is a genetic condition that typically occurs in females.  Usually we each have two sex chromosomes. Females usually have two X chromosomes, whereas males usually have one X chromosome and one Y chromosome. Turner syndrome is caused by the complete or partial absence of one X chromosome. This absence can lead to physical and developmental differences in females, including short stature, heart defects, infertility, and differences in the development of reproductive organs.

What Causes Turner Syndrome?

Turner syndrome is caused by the complete or partial absence of one of the sex chromosomes, specifically one X chromosome. This absence often results from a random error during cell division that eventually forms the  sperm or eggs. However, sometimes this absence is the result of a random error in cell division after the baby has been conceived. In this instance, some of the baby’s cells will have the normal number of sex chromosomes, but other cells will be missing all or part of one X chromosome. This is called mosaic Turner syndrome.

A Normal Karyotype

Is Turner Syndrome Inherited?

Turner syndrome is not typically inherited from a parent since it is due to random error resulting in a spontaneous genetic change that is new in the person who is affected. The chance of having a baby with Turner syndrome does not increase with the mother's age, but it can occur in any pregnancy as there are no known factors that would make someone “high-risk.”

Signs and Symptoms of Turner Syndrome

The signs and symptoms of Turner syndrome can vary widely between individuals, but common physical features include short stature, webbed neck (extra skin at the back of the neck), differences with their heart, problems surrounding their pubertal development and menstrual periods, as well as infertility. Some individuals may also experience learning and cognitive differences, and are more likely to have learning problems in certain areas especially related to spatial relationships and memory. It's important to note that not all individuals with Turner syndrome will experience the same symptoms and each individual will need a personalized and multidisciplinary approach to their medical care.

Who Should Get Prenatal Screening for Turner Syndrome?

The American College of Obstetricians and Gynecologists (ACOG) recommends that all pregnant people be offered screening for chromosomal abnormalities, which includes Turner syndrome. Discuss monosomy X genetic testing options, including the UNITY Screen™ blood test for Turner syndrome, with your doctor.

UNITY Screen™ Turner Syndrome NIPT Workflow

Consult
The UNITY Screen™ NIPT is ordered through your healthcare provider. You can schedule a complimentary genetic counseling session to answer any questions about the test before or after your blood is drawn.

Test: As early as week 10
Your blood sample can be collected in the doctor’s office, at a local lab, or through our mobile services. Your blood sample is shipped to our CAP/CLIA certified laboratory in northern California.

aneuploidy NIPT + fetal antigen results: As early as week 11
Within about one week from lab receipt, your doctor will receive the baby’s risk score for aneuploidies (chromosome conditions) and fetal antigens (if added). You will receive a text or email indicating your results are available on our portal, or your healthcare provider may call you with the results.

carrier status + single-gene NIPT results: As early as week 12
Within about two weeks from lab receipt, your doctor will receive the results of your maternal carrier status testing and single-gene NIPT. If you were found to be a carrier for any of the recessive conditions, single-gene NIPT is automatically run to determine your baby’s risk of being affected. You will receive a text or email indicating your results are available on our portal, or your healthcare provider may call you with the results.

How Accurate Is NIPT for Turner Syndrome?

UNITY Screen™ is highly accurate Turner syndrome genetic testing option that can identify pregnancies as high-risk for Turner syndrome. However, it is important to note that a positive result does not definitively mean that the baby has Turner syndrome. UNITY Screen™ is a type of Turner syndrome screening test. The results may indicate a need for further testing, such as amniocentesis or chorionic villus sampling (CVS), which can provide a diagnosis. It's important to discuss the test results with a healthcare provider to understand what they mean and decide how you would like to move forward.

The image shows a detailed UNITY™ Carrier Screen with Reflex sgNIPT report for genetic conditions from BillionToOne, Inc. The report is dated 01/29/2023, with sample type “Blood” collected on 01/18/2023. The patient information at the top of the report reads:  First Name: Jane Last Name: Doe Date of Birth: 01/01/2000 Ethnicity: Northern European/White Gender: Female Gestational Age: 10 weeks and 4 days Medical Record Number: N/A The provider listed is John Smith at 1035 O'Brien Drive, Menlo Park, CA 94025, with contact numbers.  Section 1: Carrier Screen Results The carrier screen is marked positive for the mother as a carrier of cystic fibrosis (CFTR), with low risk indicated for the fetus. Below is the table of screened conditions:  Alpha-Thalassemia (HBA1, HBA2)  Maternal Carrier Status: Negative Fetal Risk by sgNIPT: No data shown Sickle Cell Disease/Beta-Thalassemia/Hemoglobinopathies (HBB)  Maternal Carrier Status: Negative Fetal Risk by sgNIPT: No data shown Cystic Fibrosis (CFTR)  Maternal Carrier Status: Positive for mutation c.1521_1523delCTT (p.Phe508del) Fetal Risk by sgNIPT: Low Risk, with “See Results Below” note Spinal Muscular Atrophy (SMN1)  Maternal Carrier Status: Negative (2 SMN1 copies, SNP not present) Fetal Risk by sgNIPT: No data shown Section 2: sgNIPT Results – Details for Cystic Fibrosis In the sgNIPT result details section, cystic fibrosis is marked as low fetal risk. Further breakdown includes:  Fetal Risk Before sgNIPT: 1 in 96 – 1 in 376, depending on paternal status and ethnic-based risk frequencies. Fetal Risk After sgNIPT: 1 in 2800, assuming unknown paternal carrier status. Fetal Fraction: 9.9% Footer Notes The footer contains recommendations by the ACOG Committee on Genetics for carrier screening of cystic fibrosis, hemoglobinopathies, and spinal muscular atrophy for individuals planning a pregnancy or receiving prenatal care. This test evaluates for mutations in CFTR, HBB, HBA1, HBA2, and SMN1 genes. Reflex sgNIPT assesses fetal risk if the mother is identified as a carrier.  Additional follow-up information is indicated to be on the next pages of the report, including details on gene frequencies by ethnicity.

What Can I Expect If My Baby May Have Turner Syndrome?

If UNITY Screen™ results show a higher chance for a developing baby to have Turner syndrome, it's recommended that you discuss the results and the implications with your healthcare provider. Since genetic testing for Turner syndrome can be complex, your provider may refer you to a genetic counselor. At a genetic counseling appointment, you will be able to discuss your  results in great detail, as well as discuss all the diagnostic testing options available during your pregnancy or after delivery to confirm or rule out a Turner syndrome diagnosis. Early intervention and support can help individuals with Turner syndrome lead fulfilling lives.

Resources

Frequently Asked Questions

Explore our additional resources and find answers to common questions.

How is Turner syndrome treated?

Treatment for Turner syndrome is typically a combination of monitoring and surveillance for symptoms like ear infections, high blood pressure, and thyroid problems. Children with Turner syndrome and their parents may talk to their doctors about estrogen replacement therapy and the use of human growth hormone to address short stature. There are well-established guidelines for caring for girls and women with Turner syndrome that your provider will be aware of.

Can Turner syndrome be prevented?

Anyone can have a pregnancy that is affected by random genetic events, like Turner syndrome. There is nothing a person does to cause these conditions and nothing you can do to prevent them. If you and your partner want to learn more about a current pregnancy's chance of having Turner syndrome, consider talking to your doctor about UNITY Screen™.

Will being pregnant at a later age increase the risk of having a baby with Turner syndrome?

The chance for having a child with Turner syndrome does not increase with age. It can happen in pregnancies of people at any age.

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