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Disease Profile

Hypothalamic hamartomas

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)

Hamartoma of the hypothalamus


Nervous System Diseases


Hypothalamic hamartomas (HH) are rare, tumor-like malformations that occur during fetal development and are present at birth. The lesions usually do not change in size or spread to other locations. Both the type and severity of symptoms vary greatly among patients with hypothalamic hamartomas.[1] Common symptoms include frequent gelastic seizures (spontaneous laughing, giggling and/or smirking) or dacrystic seizures (crying or grunting); developmental delays; and/or precocious puberty. Additional symptoms may include cognitive impairment; emotional and behavioral difficulties; and endocrine disturbances. These symptoms often start early in life but are frequently misdiagnosed. For some patients, endocrine (hormonal) disturbances such as central precocious puberty may be the only symptom. These patients can often be treated successfully with medications. For some, however, HH can be disabling. For those with HH and epilepsy, it is common for the disorder to progress and for different types of seizures to develop. The seizures associated with HH often cannot be well-controlled with the standard seizure medications. For some, additional treatment such as surgical removal, radiosurgery, or  thermoablation may be indicated. Though hypothalamic hamartomas can occur in patients with certain genetic disorders (such as Pallister-Hall syndrome), the majority of cases are sporadic. [1][2][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:
30%-79% of people have these symptoms
Death in infancy
Infantile death
Lethal in infancy

[ more ]

Percent of people who have these symptoms is not available through HPO
Abnormal heart morphology
Abnormality of the heart
Abnormally shaped heart
Heart defect

[ more ]

Abnormality of cardiovascular system morphology
Anterior hypopituitarism
Autosomal recessive inheritance
Cleft palate
Cleft roof of mouth
Depressed nasal bridge
Depressed bridge of nose
Flat bridge of nose
Flat nasal bridge
Flat, nasal bridge
Flattened nasal bridge
Low nasal bridge
Low nasal root

[ more ]

Hip dislocation
Dislocated hips
Dislocation of hip

[ more ]

Too much cerebrospinal fluid in the brain
Hypothalamic hamartoma
Increased size of skull
Large head
Large head circumference

[ more ]

Median cleft lip
Central cleft upper lip
Abnormally small tongue
Underdevelopment of the tongue

[ more ]

Little lower jaw
Small jaw
Small lower jaw

[ more ]

Smaller or shorter than typical limbs
Short penis
Small penis

[ more ]

Occipital encephalocele
Brain tissue sticks out through back of skull
Postaxial hand polydactyly
Extra little finger
Extra pinkie finger
Extra pinky finger

[ more ]

Pulmonary hypoplasia
Small lung
Underdeveloped lung

[ more ]

Renal dysplasia
Short nose
Decreased length of nose
Shortened nose

[ more ]

Short ribs
Skeletal dysplasia


Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.


    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.

    Organizations Supporting this Disease

      Learn more

      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

      • 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

        • 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 Hypothalamic hamartomas. Click on the link to view a sample search on this topic.


          1. Kerrigan, John. Hypothalamic Hamartoma. National Organization of Rare Disorders (NORD). 2012; https://rarediseases.org/rare-diseases/hypothalamic-hamartoma/. Accessed 6/22/2016.
          2. Understanding HH. Hope for Hypothalamic Hamartoma. https://www.hopeforhh.org/what-is-hh/. Accessed 6/22/2016.
          3. Hypothalamic Hamartoma. Barrow Neurological Institute. September 8, 2015; https://www.barrowneuro.org/specialty/hypothalamic-hamartoma/. Accessed 6/22/2016.