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Living with Congenital Horner syndrome

A rare condition from birth with a small pupil, a drooping upper eyelid and less sweating on one side of the face.

Understanding Congenital Horner syndrome

Congenital Horner syndrome is a rare condition marked by a small pupil, a drooping upper eyelid and no sweating on part of the face.

It is caused by damage to the sympathetic nerves of the face. In rare cases the colored part of the eye (the iris) lacks pigment.

Signs & symptoms

Symptoms vary from person to person. GARD's summary lists these:

  • Small pupil (miosis)
  • Drooping upper eyelid (ptosis)
  • No sweating on the face (anhidrosis)
  • Lighter iris color, in rare cases

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 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
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 Horner's Syndrome: Awareness, Action and Advocacy Foundation
  • 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
What caused the nerve damage in my or my child's case?
Do we need scans or other tests?
How can eyelid or vision problems be monitored?

Quick facts

InheritanceAutosomal Dominant

It is caused by damage to the sympathetic nerves of the face. GARD lists autosomal dominant inheritance for the inherited form.

Genetic

Also known as: congenital claude bernard horner syndrome; congenital claude-bernard-horner syndrome; congenital horner syndrome (disease)

Patient organizations

Source: NIH GARD · Congenital Horner syndromeGARD ID 6670 · 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 Congenital Horner syndrome.

Explore the Congenital Horner syndrome blog

Explore research for Congenital Horner syndrome

Explore actively recruiting Congenital Horner syndrome studies with HealthSpark.

HealthSpark

Find actively recruiting studies for Congenital Horner 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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