Health and development of babies born with an extra sex chromosome (e.g., XYY, XXY, XXX)

The eXtraordinarY Babies Study: Natural History of Health and Neurodevelopment in Infants with Sex Chromosome Trisomy

NIH-funded research University of Colorado Denver · NIH-11322605

This project follows babies with an extra sex chromosome from infancy into early childhood to watch their health, growth, and early development over time.

Quick facts

Grant typeR01 grant
Study typeNIH-funded research
Funding institutionUniversity of Colorado Denver NIH-funded
Lab location1 site (Aurora, UNITED STATES)
Project IDNIH-11322605 on NIH RePORTER

What this research studies

If your baby was diagnosed with an extra sex chromosome before or after birth, this project follows them with regular check-ins to track growth, medical issues, and developmental milestones. The team collects medical histories, hormone tests, developmental exams, behavior questionnaires, and stores biospecimens in a longitudinal biobank. Visits and standardized measures focus on speech, learning, attention, social development, and medical conditions like seizures or endocrine changes. The information is used to map common paths and spot early signs that could help families and clinicians provide timely support.

Who could benefit from this research

Good fit: Infants and young children diagnosed with a sex chromosome trisomy (for example XYY, XXY/Klinefelter, or XXX/Trisomy X), especially those identified prenatally or in the first years of life, are ideal candidates.

Not a fit: People without a sex chromosome trisomy, or those seeking an immediate therapeutic treatment rather than observational follow-up, are unlikely to gain direct clinical benefit from participation.

Why it matters

Potential benefit: Findings could lead to earlier recognition of learning, behavioral, and medical issues and help guide better genetic counseling and care for affected children.

How similar studies have performed: Smaller prior studies have reported increased risks for language, learning, ADHD, and autism in SCT, and this larger prospective cohort builds on that earlier work to provide more detailed natural-history data.

Where this research is happening

Aurora, UNITED STATES

Researchers

About this research

  1. This is an active NIH-funded research project — typically early-stage science, not a clinical trial accepting patient enrollment.
  2. Some NIH-funded labs run parallel clinical studies or seek volunteers for related work. To check, contact the principal investigator or institution listed above.
  3. For full project details, budget, and progress reports, visit the official NIH RePORTER page below.
Conditions 47 XYY syndrome
Last reviewed 2026-06-10 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.