UNITY Screen™ NIPT for Jacobs Syndrome (XYY)

What Is UNITY Screen™ for Jacobs Syndrome?

UNITY Screen™ is a non-invasive prenatal test (NIPT) that looks to see if your developing baby is at high-risk for XYY syndrome as early as 10 weeks into pregnancy. The test looks at DNA from the pregnancy, which can be found in the mother's blood. UNITY Screen™ is a first-trimester screening option that can provide accurate results from a blood draw.

How UNITY for Jacobs Syndrome Works?

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What Is Jacobs Syndrome?

Jacobs syndrome, or XYY syndrome, is a genetic condition that affects males. It is caused by the presence of an extra Y chromosome, resulting in a total of 47 chromosomes instead of the typical 46. Commonly, conditions with a missing or extra sex chromosome are categorized into a group called sex chromosome aneuploidies. A diagnosis of Jacobs syndrome is confirmed in an individual with an XYY karyotype. Sex chromosomes typically contain the instructions that determine if a person is biologically male or female. Having an additional Y chromosome can lead to physical and developmental differences in males, including taller stature, delayed language skills, and differences in the development of reproductive organs.

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What Causes Jacobs Syndrome?

Jacobs syndrome is caused by the presence of an extra Y chromosome, which can occur randomly during the formation of sperm, resulting in atypical reproductive cells. However, sometimes a random event can happen after a baby has been conceived and started developing. This random event results in some cells of the developing baby being 46, XY and others being 47, XYY, this is called XYY mosaicism. Regardless of the cause, Jacobs syndrome is not inherited from a parent, but rather a spontaneous genetic change. Jacobs syndrome can occur in any pregnancy, which is why many expectant parents opt to have Jacobs syndrome testing performed during their pregnancy.

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Is Jacobs Syndrome Inherited?

Jacobs syndrome belongs to a group of conditions called sex chromosome aneuploidies, which mean a person has a different number of X or Y chromosomes than expected. These conditions happen spontaneously and are not usually passed on from an affected parent. There are no known risk factors for Jacobs syndrome and nothing a parent does can cause or prevent this from happening.

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Signs & Symptoms of Jacobs Syndrome

The signs and symptoms of Jacobs syndrome can vary widely between individuals. The majority of XYY patients do not have physical symptoms and look like other males, but common characteristics include tall stature, speech and language delays, and an increased chance for autism spectrum disorder. Some individuals may also experience learning and cognitive differences, such as difficulty with attention and executive functioning. As with many genetic disorders, it's important to note that not all individuals with Jacobs syndrome will experience the same symptoms.

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Who Should Get Prenatal Screening for Jacobs  Syndrome?

The American College of Obstetricians and Gynecologists (ACOG) recommends that all pregnant people be offered screening for specific chromosomal abnormalities, including Jacobs syndrome. Discuss screening options with your doctor to look for the extra Y chromosome that leads to Jacobs syndrome.

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UNITY Screen™ Jacobs 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.

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How Accurate Is NIPT for Jacobs Syndrome?

UNITY Screen™ is highly accurate at identifying pregnancies at high-risk for Jacobs syndrome and other chromosome disorders. However, it is important to note that a positive result does not definitively mean that the baby has Jacobs syndrome. It 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 with possible next steps.

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What Can I Expect If My Baby May Have an Extra Y Chromosome?

If UNITY Screen™ results show a higher chance for a developing baby to have an extra Y chromosome, it's recommended that you discuss the results and the implications with your healthcare provider or a genetic counselor. They will be able to explain the results, as well as diagnostic testing options available during your pregnancy or after delivery to confirm a diagnosis. Early intervention and support can help individuals with a genetic disorder, such as Jacobs syndrome, lead fulfilling lives.

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Resources

• AXYS (Variations in X and Y Chromosome)
• Unique: Understanding Rare Chromosome Disorders
• National Society of Genetic Counselors
• American College of Obstetricians and Gynecologists Guide to Prenatal Diagnosis

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Frequently Asked Questions

Explore our additional resources and find answers to common questions.

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How is Jacob Syndrome treated?

Many individuals with XYY syndrome do not realize they have the condition. The severity of symptoms can vary from one person to another. Some may benefit from extra help in school such as speech therapy, physical and occupational therapies, and/or social support. Some children have challenges with social communication and may be diagnosed with autism spectrum disorder. Usually XYY syndrome does not cause learning disabilities or intellectual disabilities.

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Can Jacob syndrome be prevented?

There is nothing you can do to cause or prevent XYY syndrome. Since it is a spontaneous genetic condition, some families pursue genetic counseling and prenatal testing or screening for XYY syndrome, to understand more about their chance to have an affected baby.

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What is the inheritance pattern for Jacob syndrome?

XYY syndrome is not usually inherited. This is typically a chromosome change that happens randomly at conception. There is nothing you can do to cause or prevent XYY syndrome.