X & Y Chromosome Variations

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X & Y Chromosome Variations

Coordinated Care, All in One Place


The Nemours eXtraordinarY Kids Program offers expert, full-service, integrated medical care and support services for children with X and Y chromosome abnormalities. These are variations of the X and Y chromosomes, which determine a child’s sex — male or female. Normally, a child will be a male if he inherits one X chromosome from his mother and one Y chromosome from his father. A child will be a female if she inherits a double dose of X (one from each parent) and no Y. Sometimes, though, children are born with only one sex chromosome (usually a single X chromosome) or with an extra X or Y chromosome.

At Nemours, our eXtraordinarY Kids team will give your child a thorough evaluation and create a treatment plan tailored to your child’s medical care, development, academic, social and emotional needs. Our program was created to help families identify needs and resources — and to provide coordinated care, all in one place. Our goal: to help the children we see reach their full potential.

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X & Y Chromosome Conditions We Treat

X & Y Chromosome Conditions We Treat


X and Y chromosome abnormalities are common. But they’re often undiagnosed genetic conditions that can impact a child’s development and physical characteristics. Symptoms can vary from mild to severe. They may include physical, hormonal, neurocognitive, psychiatric and social issues like delayed pubertal development, speech delays, low muscle tone, attention deficits and social immaturity.

The conditions we treat are:

  • Klinefelter syndrome (also called “XXY syndrome,” when a boy is born with an extra X chromosome in most or all of their cells)
  • Turner syndrome (when a girl is born with only one X chromosome or is missing part of an X chromosome)
  • XXX syndrome (also known as “triple X syndrome,” “trisomy X” and “47,XXX,” when a girl is born with an extra X chromosome in most or all of their cells)
  • XYY syndrome (when a boy is born with an extra Y chromosome in most or all of their cells)
Our Team

Our Team


The Nemours eXtraordinarY kids team combines the efforts of multiple health professionals from various fields — all working together to give your child the best care possible. Our team is led by pediatric endocrinologist Dr. Judith Ross , who has devoted most of her career to studying and treating X and Y chromosome variations. She provides overall guidance about physical features, hormonal/endocrine issues and treatment, neurodevelopmental and genetic aspects, and any related medical concern.

Kids’ full-service care is coordinated by our physician assistant (PA), who has more than 25 years of experience working with families of children with X and Y chromosome abnormalities.

Our team also includes:

Why Choose Us for X & Y Chromosome Variations

Why Choose Us for X & Y Chromosome Variations


Our Nemours eXtraordinarY Kids Program team has the expertise to give an accurate diagnosis and recommend proper treatments for conditions like Klinefelter, Turner, XXX and XYY syndrome. We know that with the right diagnosis and care, children with X and Y chromosome variations can succeed academically, physically and socially — and can lead independent, productive lives.

Nemours eXtraordinarY Kids Program Highlights

At the Nemours eXtraordinarY Kids Program, located at Nemours/Alfred I. duPont Hospital for Children in Wilmington, Del., we include parents and family members as key members of the care team. That means we involve you in treatment plan decisions and make sure you understand your child’s condition and care.

We’re also very active in research and clinical trials. We study the medical problems, genetic factors, development, learning, behavior and motor skills in children and young adults with X and Y chromosome abnormalities. We’re always seeking better treatments and diagnostic methods.

We’re currently recruiting patients and families for an active clinical trial in this area.

Learn More About Our Clinical Trial »

Learn More About the Nemours eXtraordinarY Kids Program (PDF) »

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Research & Clinical Trials

At Nemours, we’re actively researching new approaches for childhood disease prevention, diagnosis and treatment.

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KidsHealth Library

Learn more about your child’s medical condition from the experts at Nemours’ KidsHealth.