Research on health and development in infants with sex chromosome trisomy

The eXtroardinarY Babies Study: Natural History of Health and Neurodevelopment in Infants and Young Children With Sex Chromosome Trisomy

Observational University of Colorado, Denver · NCT03396562

This study looks at the health and development of infants with sex chromosome trisomies, like Klinefelter syndrome, to see how they grow and what early signs can help doctors provide better care.

Quick facts

Study typeObservational
Enrollment300 (estimated)
Ages6 Weeks to 13 Months
SexAll
SponsorUniversity of Colorado, Denver Academic / other
Locations2 sites (Aurora, Colorado and 1 other locations)
Trial IDNCT03396562 on ClinicalTrials.gov

What this trial studies

This observational study investigates the natural history of health, neurodevelopment, and early hormonal function in infants with sex chromosome trisomies, including Klinefelter syndrome and others. The research aims to identify early predictors of developmental and health outcomes while evaluating various developmental screening tools. By studying a cohort of infants diagnosed prenatally, the study seeks to improve care recommendations for pediatricians managing these conditions. The findings could enhance understanding of the phenotypic spectrum associated with sex chromosome variations.

Who should consider this trial

Good fit: Ideal candidates include infants aged 6 weeks to 12 months with a confirmed prenatal diagnosis of sex chromosome aneuploidy.

Not a fit: Patients with other significant genetic or metabolic disorders or complex congenital malformations may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could lead to improved early identification and intervention strategies for infants with sex chromosome trisomies, enhancing their developmental outcomes.

How similar studies have performed: While there is limited recent research on this topic, historical studies from the 1970s suggest a need for updated understanding, making this approach novel.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

1. Prenatal diagnosis of sex chromosome aneuploidy (by cfDNA, chorionic villi sampling, and/or amniocentesis)
2. Postnatal confirmatory karyotype of XXY, XYY, XXX, XXYY, XYYY, XXXY, XXXX, XXXXX, XXXXY, XXXYY, XXYYY, XYYYY (including any mosaicism with \<80% 46,XX or 46,XY cell line)
3. English or Spanish speaking
4. Age 6 weeks to 12 months 30 days on enrollment

Exclusion Criteria:

1. Previous diagnosis of a different genetic or metabolic disorder with neurodevelopmental or endocrine involvement
2. Prematurity less than 34 weeks gestational age
3. Complex congenital malformation not previously associated with sex chromosome aneuploidy
4. History of significant neonatal complications (ie intraventricular hemorrhage, meningitis, hypoxic-ischemic encephalopathy)
5. Known complex Central Nervous System (CNS) malformation identified by neuroimaging

Where this trial is running

Aurora, Colorado and 1 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Klinefelter SyndromeTrisomy XXYY SyndromeXXXY and XXXXY SyndromeXxyy SyndromeXyyy SyndromeXxxx SyndromeXxxxx 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.