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Living with Mosaic trisomy 15

A rare chromosome condition with slow growth before birth, heart differences, and facial, brain, kidney, and genital differences.

Understanding Mosaic trisomy 15

Mosaic trisomy 15 is a rare chromosome condition in which some cells have an extra copy of chromosome 15.

It is mainly marked by slow growth before birth, heart differences present from birth, and certain facial features, such as eyes set far apart. People may also have differences in the brain, kidneys, or genitals. Differences in the fingers and skin color have also been reported. Signs are seen during pregnancy or in the newborn period.

Signs & symptoms

Symptoms vary from person to person. GARD lists these among the most common:

  • Low muscle tone (hypotonia)
  • Fingers that stay bent (camptodactyly)
  • Fingers that angle sideways
  • Differences in the hand
  • Differences in the nervous system

Not everyone has every symptom. GARD's list comes from the Human Phenotype Ontology.

Diagnosis

  1. Talk with your doctor

    Share the symptoms you've noticed, when they started and your family health history. Notes and photos can help.

  2. See a specialist

    Specialists who may be involved include genetic specialists.

  3. Ask which tests can help

    Your care team will decide which exams and tests can confirm the diagnosis.

Care & treatment

Care team
Genetic specialists (geneticists)
Expert care
Ask about multidisciplinary care centers for rare conditions
Treatment
GARD doesn't list specific treatments for this condition. Your care team will tailor care to your symptoms.
Research
Clinical trials and observational studies may be options. See the research section below.

General information, not medical advice. Your care team makes the decisions.

Everyday life

Living with a rare condition is easier with support.

  • Connect with Chromosome Disorder Outreach
  • Keep notes on symptoms, changes and questions for appointments
  • Ask about patient registries that help research
  • Look into financial aid and travel resources for care visits
Bring these questions to your next doctor visit
Which tests confirm the mosaic pattern?
Which specialists should check the heart, kidneys, and brain?
What supports are available for growth and development?

Quick facts

Symptoms usually startduring Pregnancy and as a Newborn

This condition is caused by an extra copy of chromosome 15 in some, but not all, of the body's cells. GARD says changes in genes (also called variants) cause it.

Genetic

Also known as: mosaic trisomy 15 syndrome; mosaic trisomy chromosome 15; mosaic trisomy type 15; trisomy 15 mosaicism; uniparental disomy of 15

Patient organizations

Broader rare-disease groups

Source: NIH GARD · Mosaic trisomy 15GARD ID 5313 · GARD page updated September 2026 · Plain-language summary by Know Rare; editorial review pending. General information, not medical advice.

You are more than your diagnosis

Perspectives from people navigating life with Mosaic trisomy 15.

Explore the Mosaic trisomy 15 blog

Explore research for Mosaic trisomy 15

Explore actively recruiting Mosaic trisomy 15 studies with HealthSpark.

HealthSpark

Find actively recruiting studies for Mosaic trisomy 15 with HealthSpark. Share your city to explore research near you.

  • Recruiting studies from ClinicalTrials.gov
  • Share your city to look for research near you
  • Eligibility is confirmed by the study team

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Powered by HealthSpark, our AI chat helper · Study information from ClinicalTrials.gov · Eligibility is confirmed by the study team.

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