The eXtraordinarY Kids Research Program

Since 2007, our eXtraordinarY Kids Clinic team has been conducting clinical research in X&Y chromosome variations in order to learn more about the medical problems, developmental milestones, learning, language, motor skills, behavior and emotions in a wide age-range of individuals with X&Y chromosome variations.  
Through research, we hope to better understand the strengths and weaknesses for individuals with X&Y chromosome variations, as well as how genes on the X&Y chromosomes may influence these different areas.

eXtraordinarY Kids Research Newsletters 

Current Research Opportunities

We are actively conducting the research studies below.  If you are interested in learning more about a specific study, please contact us!
eXtraordinarY Babies Study: Researching the Natural History of Health and Neurodevelopment in Infants and Young Children with Sex Chromosome Trisomy
Purpose of the study:
This study is designed to research the natural history of neurodevelopment, health and early hormonal function in infants with XXY/Klinefelter syndrome, XYY, XXX and other sex chromosome variations in an effort to identify early predictors of developmental and health outcomes. We will also evaluate different developmental screening tools in infants with sex chromosome variations so we can develop recommendations for pediatrician caring for infants and young children with XXY/Klinefelter syndrome, XYY, XXX, and other sex chromosome variations.
What’s Involved:

Children age 6 weeks to 12 months old, who have a prenatal diagnosis of XXY, XYY, XXX, XXYY, and other sex chromosome variations are eligible.

  • 4-8 study visits over 2-4 years, depending on age and timing of enrollment
Assessments will include:
  • Measures of skills in different areas of development including problem solving, language, social, motor, and life skills.
  • Physical exam
  • Blood, urine, and stool testing for hormone levels, metabolic functioning and DNA banking.
  • Scans for body composition (muscle and fat mass, bone density)
  • Quality of life outcomes
  • Questionnaires & surveys to be completed by parents or caregivers
Study sites include Colorado or Delaware. Travel budget included if needed.
PI: Nicole Tartaglia, MD (Colorado) and Co-Investigator: Judith Ross, MD (Delaware)
To learn more about this study, contact 720-808-0873 or email

(COMIRB# 17-0118, ; PI Dr. Nicole Tartaglia; funded by NIH/NICHD; Identifier: NCT03396562)


The TESTO Research Study
Testosterone Effects on Short Term Outcomes in XXY

Purpose of the Research Study:

This research study will learn more about the effects of testosterone shots on body fat and development in infants with XXY / Klinefelter syndrome.

What’s Involved:

This study is 6 months long and includes 3 in-person visits at the Children’s Hospital Colorado. At the visits your baby will have a:

  • developmental evaluation
  • body fat measurement in a special scale
  • a blood draw, urine and stool collection
  • physical examination

All infants in the study will receive testosterone shots.

If you have an infant with XXY less than 3 months old and are interested in learning more about this study, contact us at or 720-777-6774.

(COMIRB# 17-1317; PI Dr. Shanlee Davis; funded by NIH/NICHD; Identifier: NCT03325647)         

Growing up with X and Y Trisomy: The TriXY Study (Aug. 2019 Closed to Enrollment)

Development can vary in children with an extra X or Y chromosome. It is therefore important to identify children with develop-mental differences so that appropriate interventions and supports can be provided as soon as possible.  We have limited knowledge about development in these areas in young children with an extra X or Y chromosome, and there is still a lot for us to learn. In this study we are hoping to identify early markers to know which children are at higher risk for behavior differences. With this knowledge we hope to understand risk and protective factors which will then allow us to provide better care for infants with a diagnosis of XXY, XXX or XYY.
Why is study being done:
To better understand the early neuropsychological and social development of children with XXY, XYY and XXX.
Who can participate:
Children ages 1 year – 5 years old with any of the following conditions: XXY, XYY or XXX
What does the study include?
  • We will ask you questions about the development of your child in person and with online questionnaires
  • Your child will participate in some developmental tests where they will play with puzzles and blocks, and look at pictures
  • We will assess your child’s behavior while looking at pictures and videos while wearing stickers that measure their body’s response
How long is the study:
Children will be seen for 2 visits; 1 at baseline and 1 twelve months later.  Each visit will be for 1.5-2 days.
More Information:  

Contact or 720-722-1515

(COMIRB# 17-1710; Enrollment Period October 2017-June 2019; PI Dr. Nicole Tartaglia; funded by Leiden University, Netherlands awarded to Dr. Sophie van Rijn)



Previous Studies (No Longer Enrolling)

The Effects of Testosterone Therapy in Young Adolescents with Klinefelter Syndrome

(COMIRB# 11-0874; PI Dr. Nicole Tartaglia; April 2012-October 2017; funded by NIH/NINDS)

This study investigated the effects of testosterone therapy on behavior, mood, problem solving, attention span and motor skills in adolescent males with Klinefelter syndrome in early puberty. During this period in early puberty, there is much variability in how and when doctors start testosterone therapy. This study evaluated if there are benefits to starting testosterone therapy in early puberty. 

Participants with Klinefelter syndrome in early puberty (around ages 10 to 15) were treated with either testosterone gel or a place