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Disease Profile

Horner’s syndrome

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.


US Estimated

Europe Estimated

Age of onset





Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.


Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other names (AKA)

Bernard-Horner Syndrome; Oculosympathetic Palsy


Horner's syndrome is a rare condition characterized by miosis (constriction of the pupil), ptosis (drooping of the upper eyelid), and anhidrosis (absence of sweating of the face).[1][2] It is caused by damage to the sympathetic nerves of the face. The underlying causes of Horner's syndrome vary greatly and may include a tumor, stroke, injury, or underlying disease affecting the areas surrounding the sympathetic nerves. In rare cases, Horner's syndrome is congenital (present from birth) and may be associated with a lack of pigmentation of the iris (colored part of the eye).[1][2][3] Treatment of Horner's syndrome depends on the underlying cause.[3]


Symptoms of Horner's syndrome typically include drooping of the upper eyelid (ptosis), constriction of the pupil (miosis), sinking of the eyeball into the face, and decreased sweating on the affected side of the face (anhidrosis). These symptoms may vary and other symptoms may occur depending on the underlying cause of the condition.[1][2] Other symptoms which may be seen include the inability to completely close or open the eyelid, facial flushing, headaches, and pain.[2][3] 

Heterochromia iridium (i.e., a relative deficiency of pigment in the iris of affected side of the face) is usually present when the syndrome is congenital or caused by a lesion that has occurred before the age of 1-2 years of age.[3]

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Medical Terms Other Names
Learn More:
Percent of people who have these symptoms is not available through HPO
Autosomal dominant inheritance
Congenital Horner syndrome
Deeply set eye
Deep set eye
Deep-set eyes
Sunken eye

[ more ]

Heterochromia iridis
Different colored eyes
Ipsilateral lack of facial sweating
Inability to move


There are many potential causes of Horner's syndrome. It can be caused by any interruption in function of the sympathetic nerve fibers, which start in the hypothalamus and run via the upper spinal cord, near the carotid artery, to the face. Nerve function may be impaired due to factors such as injury, compression, or a disease process. Examples of causes of Horner's syndrome include:[1][2][3][4]

  • Birth trauma to the neck and shoulder.
  • A stroke in the brainstem.
  • Injury, blood clot, or dissection of the carotid artery.
  • Trauma or surgery involving the neck, upper spinal cord, or chest.
  • A tumor in the brainstem, hypothalamus, upper spinal cord, neck, eye, abdomen, or chest cavity particularly a neuroblastoma or a tumor of the upper part of the lung (Pancoast tumor). Neuroblastoma is one of the most common causes of Horner's syndrome in children.
  • Migraines or cluster headaches.
  • Diseases that cause damage to the protective covering that surrounds nerve fibers (demyelinating diseases).
  • Development of a fluid-filled cavity or cyst within the spinal cord (syringomyelia).
  • Arnold-Chiari malformation.
  • Inflammation or growths that affect the lymph nodes of the neck.


An ophthalmologist may confirm the diagnosis by special eye tests.[5] In addition, a careful neurological exam may be necessary to find the cause by determining which, if any, other parts of the nervous system are affected. Tests may include[1]:


Treatment depends on the underlying cause. There is no specific treatment for Horner's syndrome itself.[1] In many cases, no effective treatment is known.[3]


Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Social Networking Websites

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These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

  • MayoClinic.com offers additional information about Horner syndrome. Click on the above link to access this information.
  • MedlinePlus was designed by the National Library of Medicine to help you research your health questions, and it provides more information about this topic.
  • Genetics Home Reference contains information on Horner's syndrome. This website is maintained by the National Library of Medicine.
  • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.

In-Depth Information

  • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Horner's syndrome. Click on the link to view a sample search on this topic.


  1. Horner syndrome. MedlinePlus. May 30, 2016; https://www.nlm.nih.gov/medlineplus/ency/article/000708.htm.
  2. Horner's syndrome. National Organization for Rare Disorders (NORD). 2003; https://rarediseases.org/rare-diseases/horners-syndrome/.
  3. Bardorf, CM. Horner Syndrome. Medscape. May 17, 2016; https://emedicine.medscape.com/article/1220091.
  4. Kedar S, Biousse V, Newman NJ. Horner syndrome. UpToDate. Waltham, MA: UpToDate; June 19, 2018; https://www.uptodate.com/contents/horner-syndrome.
  5. Dennis Robertson. Horner syndrome: What causes it?. MayoClinic.com. May 06, 2014; https://www.mayoclinic.org/diseases-conditions/horner-syndrome/basics/definition/con-20034650.

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