UNITY Screen™ NIPT for Klinefelter (XXY) Syndrome

Klinefelter syndrome, or XXY syndrome, is a genetic condition that occurs in males. It is caused by the presence of an extra X chromosome, resulting in a total of 47 chromosomes instead of the typical 46. UNITY Screen™ provides a non-invasive prenatal screening designed to provide an assessment of your baby's chance for Klinefelter syndrome and other chromosome conditions.

Incidence at Birth

Klinefelter syndrome occurs in 1 in 500 male births.

Common Names

XXY syndrome is another name for Klinefelter syndrome.

Causes

This condition is caused by a male having an extra copy of their X chromosomes (47,XXY).

What Is UNITY Screen™ for Klinefelter Syndrome?

UNITY Screen™ is a non-invasive prenatal test (NIPT) that can tell you if your pregnancy is high-risk for Klinefelter syndrome. This Klinefelter syndrome NIPT is a type of prenatal screening that can be performed as early as 10 weeks into pregnancy. The test analyzes the genetic material from the pregnancy found in the mother's blood.  If your pregnancy is considered high-risk, your healthcare provider will discuss additional Klinefelter syndrome genetic testing options that can confirm or rule out the diagnosis. 

How UNITY for Klinefelter Syndrome Works?

What Is Klinefelter Syndrome?

People are usually born with two sex chromosomes. Females usually have two X chromosomes, whereas males usually have one X chromosome and one Y chromosome. Klinefelter syndrome, or XXY syndrome, is a genetic condition that occurs in males. It is caused by the presence of an extra X chromosome, resulting in a total of 47 chromosomes instead of the typical 46. This extra genetic material can lead to physical and developmental differences in males, including taller stature, delayed language skills, and differences in the development of reproductive organs.

What Causes Klinefelter Syndrome?

Klinefelter syndrome is caused by the presence of an extra X chromosome, which occurs randomly during the formation of sperm or eggs. Klinefelter syndrome is a genetic condition that is often grouped into what are called sex chromosome aneuploidies. Sex chromosome aneuploidies all involve an extra or missing sex chromosome (X or Y chromosomes) and are not typically inherited from a parent, but rather a spontaneous genetic change that is new in the person affected. The chance of having a baby with Klinefelter syndrome increases slightly as a mother gets older, but can occur in any pregnancy.

A Normal Karyotype

Is Klinefelter syndrome inherited?

Sex chromosome differences like Klinefelter syndrome are not typically inherited from a parent. These changes occur randomly at the time of conception and are usually new in the person who is affected. A mother’s age can increase the risk slightly for an affected pregnancy, but Klinefelter syndrome is common and can occur in any pregnancy. There are no other known risk factors, and nothing parents can do to cause or prevent this from happening.

Signs & Symptoms of Klinefelter Syndrome

The signs and symptoms of Klinefelter syndrome can vary widely between individuals, but many do share common physical characteristics. When compared to other family members, individuals with Klinefelter syndrome are usually taller in stature. Compared to other males, people with Klinefelter syndrome typically have less muscle mass and gynecomastia (enlarged breast tissue). Some individuals may also experience learning disabilities and cognitive differences. Many children with Klinefelter syndrome have challenges with social communication or interaction skills and may be diagnosed with autism spectrum disorder. Men with Klinefelter syndrome often have incomplete sexual development and infertility. It's important to note that not all individuals with Klinefelter syndrome will experience the same symptoms.

Who Should Get Prenatal Screening for Klinefelter Syndrome?

The American College of Obstetricians and Gynecologists (ACOG) recommends that all pregnant people be offered screening for chromosomal abnormalities, including Klinefelter syndrome. Discussing options to test for Klinefelter syndrome with your doctor is recommended, especially for women who are older or have had a previous pregnancy affected by a chromosome condition.

UNITY Screen™ Klinefelter 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 Klinefelter Syndrome?

There are many Klinefelter syndrome test options for expecting parents. UNITY Screen™ is a non-invasive prenatal testing option, which means it poses no physical risk to you or your baby, and is highly accurate at identifying pregnancies at high-risk for Klinefelter syndrome. Since it is a prenatal screening test, a positive result does not definitively mean that the baby has Klinefelter syndrome. It may indicate a need for further testing, such as amniocentesis or chorionic villus sampling (CVS), which can confirm or rule out a Klinefelter syndrome diagnosis. It's important to discuss test results with a healthcare provider to understand what they mean and decide how you would like to move forward with possible next steps.

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

Many children with Klinefelter syndrome may not show any physical signs or symptoms of Klinefelter syndrome, and some men are not diagnosed until adulthood. However, some children diagnosed with Klinefelter syndrome may benefit from extra help in school therapies such as speech, occupational, physical therapies, and/or social support. Hormone replacement therapy can promote puberty and improve bone strength and mood. Sometimes fertility treatment can help men with Klinefelter syndrome to have biological children when they are ready to start families of their own.

It’s important to discuss any genetic testing for Klinefelter syndrome results with your healthcare provider. If UNITY Screen™ NIPT for Klinefelter syndrome results show a higher chance for an affected baby, your doctor or a genetic counselor will be able to review them in detail and discuss further prenatal testing for Klinefelter syndrome if desired, or postnatal confirmation. We also offer complimentary genetic counseling services to discuss test results with you and your partner, or your provider.

Resources

Frequently Asked Questions

Explore our additional resources and find answers to common questions.

How is Klinefelter syndrome treated?

Klinefelter syndrome can be managed by treating the symptoms — often including (testosterone) hormone replacement therapy, physical therapy, speech and occupational therapy and behavioral therapy. Some individuals may experience learning difficulties or have challenges with social communication or interaction skills, which can be addressed with emotional or behavioral therapy. Each person will have different symptoms and respond to different therapies, so it's important to work closely with your child’s provider.

Can Klinefelter syndrome be prevented?

Klinefelter syndrome is not usually inherited, so there is usually no family history of this condition. This is typically a chromosome change that happens randomly at the time of conception. There is nothing you can do to cause or prevent Klinefelter syndrome. Since it is a random genetic event, some families pursue prenatal testing or screening for Klinefelter syndrome, to understand more about their chance to have an affected baby.

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