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Living with 3p- syndrome

A rare chromosome condition, from a missing piece at the end of chromosome 3, that can bring slow growth and developmental delay.

Understanding 3p- syndrome

3p- syndrome, also called distal monosomy 3p, is a rare chromosome condition with a missing piece of chromosome 3.

Severity depends on the size and location of the deletion. Some people have no or mild features, while others are more affected. Common features include poor growth, developmental delay, intellectual disability, distinct facial features, autism spectrum disorder, a small head, and low muscle tone. Most cases are not inherited, but people can pass the deletion to their children. GARD lists onset as during pregnancy and as a newborn.

Signs & symptoms

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

  • Small head size (microcephaly)
  • Low muscle tone (hypotonia)
  • Short stature
  • Cleft palate
  • Hearing impairment
  • Intellectual or cognitive impairment

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 brain and nervous system specialists, eye disease specialists and 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
Brain and nervous system specialists (neurologists); Eye disease specialists (ophthalmologists); 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
How large is the deletion in my child, and what does that mean?
Does my child need a hearing test or a cleft palate evaluation?
Should we get genetic counseling about passing it on?

Quick facts

Symptoms usually startduring Pregnancy and as a Newborn
InheritanceAutosomal Dominant

GARD says changes in genes (also called variants) cause this condition. It is a missing piece of chromosome 3, it is listed as autosomal dominant, and most cases are not inherited.

GeneticNeurological

Also known as: 3p deletion syndrome; 3p syndrome; chromosome 3, deletion 3p; chromosome 3, monosomy 3p; chromosome 3, monosomy 3p25; chromosome 3pter-p25 deletion syndrome

Patient organizations

Broader rare-disease groups

Source: NIH GARD · 3p- syndromeGARD ID 3750 · 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 3p- syndrome.

Explore the 3p- syndrome blog

Explore research for 3p- syndrome

Explore actively recruiting 3p- syndrome studies with HealthSpark.

HealthSpark

Find actively recruiting studies for 3p- syndrome 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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