Klinefelter Syndrome Program

The Klinefelter Syndrome Program at Lurie Children's offers interdisciplinary care—spanning from prenatal consultation to young adulthood—for individuals with Klinefelter Syndrome (also referred to as 47,XXY). The program was developed as our team saw a clear need for access to coordinated expertise to address the medical, developmental and psychosocial needs of this population. 

What Is Klinefelter Syndrome?

Klinefelter syndrome is a relatively common genetic difference seen in approximately 1 in 600 individuals with male sex. Individuals with Klinefelter syndrome have an extra X chromosome in the cells of their body. Their chromosomes or karyotype is 47, XXY compared to the most common karyotype among males of 46,XY.

The extra X chromosome in individuals with Klinefelter syndrome provides more genetic “instructions” than is typical in the cells of the body. This can lead to differences in health and development, which can impact various body systems. These differences can include:

  • Low muscle tone
  • Delayed speech and motor milestones
  • Learning disabilities
  • Behavior differences
  • Tall stature, or being taller than expected based on family member heights
  • Low levels of testosterone
  • Late or absent puberty
  • Infertility or difficulty conceiving a pregnancy
  • Autoimmune disorders, like thyroid disease

It is important to note that Klinefelter syndrome is highly variable. Some people have many of the above listed health findings, while others have few. Unfortunately, we cannot predict which health findings someone may or may not have. So, it is important for all people with Klinefelter syndrome to receive regular care with knowledgeable clinicians.

The Lurie Children's Difference

At Lurie Children's, our team is focused on family-centered, multidisciplinary care. For our Klinefelter Syndrome Program, this includes: 

  • Prenatal Consultation: We provide prenatal consultation for parents expecting an infant with Klinefelter syndrome through The Chicago Institute for Fetal Health which includes genetic counseling and discussion with a pediatric endocrinologist.
  • Fertility Preservation: Lurie Children’s is also home to the Fertility & Hormone Preservation & Restoration Program, which provides clinical care and completes translational and basic science research for pediatric conditions with risks of infertility. Courtney Finlayson, MD, as well as our pediatric and adult urologists and genetic counselors, are members of this program and have a particular interest in fertility preservation for people with Klinefelter syndrome.
  • Patient & Family Support: Our program values the importance of psychosocial support for individuals and families. We participate in parent and peer support initiatives through the hospital and host events to help individuals and families meet each other and develop a community. We strive to provide our families with a safe and positive atmosphere to ask questions, provide feedback and feel heard.

Conditions We Treat

Our program focuses on Klinefelter syndrome (47,XXY), but provides care for other X and Y chromosome variations, including 47,XYY, 48,XXYY, and 48,XXXY, and 49,XXXXY. 

Lurie Children's Division of Endocrinology has a separate program for children with Turner syndrome (45,X) and a genetic counseling clinic for children with Triple X syndrome (47,XXX). For information, please call the Division of Endocrinology at 312.227.6090.

Our Specialists

Our multidisciplinary staff is dedicated to evaluating and treating pediatric patients from infancy through young adulthood. These specialists include:

What to Expect

First Appointment

The first appointment in our clinic typically lasts 1-2 hours. Expect to meet with an endocrinologist and genetic counselor. Much of this time is spent discussing Klinefelter syndrome and our approach to care. Patients will have a physical exam with the endocrinologist, and we may recommend visiting the on-site lab after the appointment to check hormone levels.

In advance of the initial appointment, please provide copies of your child’s medical records, including:

  • Recent pediatrician note
  • Notes from any specialists (e.g., Endocrinology, Neurology, Developmental Pediatrics, Genetics)
  • Growth charts
  • Chromosome analysis (karyotype) genetic test report
  • Any hormone lab reports (if age appropriate)

We also recommend bringing a list of your questions to the appointment to ensure that we address your concerns.

Return Appointment

We recommend patients are seen in our clinic every 1-2 years during childhood. Around the time of puberty (~11-12 years of age), we recommend more frequent appointments. Return appointments may be short (~30 minutes) or long (1-2 hours) depending on the patient and their needs.

Patients returning to our clinic for follow up can expect to meet with the endocrinologist and genetic counselor to address their health and receive education. Additional specialists are determined based on patient age and needs. For example, our urologists are available to meet with adolescents interested in learning more about fertility preservation. Return appointments are also a good time for patients and families to ask questions and learn updates about advances in Klinefelter syndrome care and research. 

We may recommend visiting the on-site lab after the appointment to check hormone levels.

Neuropsychology Testing

We recommend all individuals with Klinefelter syndrome have neuropsychology testing around the time of school entry (1st or 2nd grade). Testing should be repeated at school transitions, such as before middle school, before high school, and before high school graduation. This type of testing identifies a child’s learning strengths as well as challenges, including attention, memory, language, visual reasoning, and thinking speed.

Common learning challenges for people with Klinefelter syndrome can include ADHD and reading/language based learning disabilities. The information from this testing helps children who need it receive support at school to promote academic excellence.

Neuropsychology testing can take 3-5 hours to complete, so it recommended to schedule an appointment on a separate day.


Make an Appointment

To make an appointment or for more information about the Klinefelter Syndrome Program, you can contact Danielle Lee at 312.227.6203 or by email at leeda@luriechildrens.org.

Resources & Support

For additional information about Klinefelter syndrome, we recommend the following:


As a member of GALAXY registry, our team is active in research and in other projects aiming to improve care for individuals with Klinefelter syndrome.

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