Overview
Sex chromosome difference of sex development (DSD) is a group of conditions where a person's sex chromosomes (the X and Y chromosomes) do not follow the typical XX (female) or XY (male) pattern, leading to differences in how the body develops sexually. Common examples include Turner syndrome (where a girl has only one X chromosome, written as 45,X), Klinefelter syndrome (where a boy has an extra X chromosome, written as 47,XXY), and mixed gonadal dysgenesis (where some cells have one chromosome pattern and others have a different one, such as 45,X/46,XY). These conditions can affect how the reproductive organs, hormones, and secondary sex characteristics (like breast development or facial hair) develop. Some people are diagnosed at birth because of differences in the appearance of the genitals, while others may not be diagnosed until puberty when expected changes do not occur, or even in adulthood when they have difficulty having children. Symptoms vary widely depending on the specific chromosome pattern and can include ambiguous genitalia, delayed or absent puberty, short stature, infertility, and differences in learning or behavior. Treatment is individualized and may include hormone replacement therapy, surgical options, fertility support, and psychological counseling. A team of specialists typically works together to provide comprehensive care tailored to each person's needs and preferences.
Key symptoms:
Ambiguous or atypical genitalia at birthDelayed puberty or absent pubertyShort stature or unusually tall statureInfertility or difficulty having childrenUndescended testiclesSmall testes or ovarian differencesBreast development in males (gynecomastia)Absent or irregular menstrual periodsDifferences in body proportionsLearning difficulties or attention problemsLow energy or fatigue related to hormone levelsBone density problems (osteoporosis)Heart or kidney differences (especially in Turner syndrome)Mood changes or anxiety
Sporadic
Usually appears on its own, not inherited from a parent
Variable
Can begin at different ages, from infancy through adulthood
FDA & Trial Timeline
3 eventsRigshospitalet, Denmark
Lise Aksglæde — PHASE4
University of Colorado, Denver — PHASE4
Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.
Treatments
No FDA-approved treatments are currently listed for Sex chromosome difference of sex development.
3 clinical trialsare actively recruiting — trials can provide access to cutting-edge therapies.
View clinical trials →Treatment Centers
8 centersBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
🏥 NORDStanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🔬 UDNUCLA UDN Clinical Site ↗
UCLA Health
📍 Los Angeles, CA
🔬 UDNBaylor College of Medicine UDN Clinical Site ↗
Baylor College of Medicine
📍 Houston, TX
🔬 UDNHarvard/MGH UDN Clinical Site ↗
Massachusetts General Hospital
📍 Boston, MA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🏥 NORDUCLA Rare Disease Day Program ↗
UCLA Health
📍 Los Angeles, CA
Travel Grants
No travel grants are currently matched to Sex chromosome difference of sex development.
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Caregiver Resources
NORD Caregiver Resources
Support, advocacy, and financial assistance for caregivers of rare disease patients.
Mental Health Support
Rare disease caregiving can be isolating. Connect with counseling and peer support.
Family & Caregiver Grants
Financial assistance programs specifically for caregivers of rare disease patients.
Social Security Disability
Learn how rare disease patients may qualify for SSDI/SSI benefits.
Questions for your doctor
Bring these to your next appointment
- Q1.What is my (or my child's) exact chromosome pattern, and what does it mean for health and development?,Will hormone therapy be needed, and when should it start?,Is there any increased risk of tumors in the gonads, and how will this be monitored?,What are the options for fertility in the future?,Are there any heart, kidney, or bone health concerns that need regular screening?,Should we see a psychologist or counselor who specializes in differences of sex development?,Are there any decisions about surgery that need to be made now, or can they wait until the patient can participate in the decision?
Common questions about Sex chromosome difference of sex development
What is Sex chromosome difference of sex development?
Sex chromosome difference of sex development (DSD) is a group of conditions where a person's sex chromosomes (the X and Y chromosomes) do not follow the typical XX (female) or XY (male) pattern, leading to differences in how the body develops sexually. Common examples include Turner syndrome (where a girl has only one X chromosome, written as 45,X), Klinefelter syndrome (where a boy has an extra X chromosome, written as 47,XXY), and mixed gonadal dysgenesis (where some cells have one chromosome pattern and others have a different one, such as 45,X/46,XY). These conditions can affect how the re
How is Sex chromosome difference of sex development inherited?
Sex chromosome difference of sex development follows a sporadic inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
Are there clinical trials for Sex chromosome difference of sex development?
Yes — 3 recruiting clinical trials are currently listed for Sex chromosome difference of sex development on UniteRare. See the clinical trials section on this page for phase, sponsor, and site details sourced from ClinicalTrials.gov.
Which specialists treat Sex chromosome difference of sex development?
2 specialists and care centers treating Sex chromosome difference of sex development are listed on UniteRare, sourced from ClinicalTrials.gov principal investigators, published research, and the NPPES NPI registry.