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Questions about rare diseases?
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Disease Information

Summary
Homozygous familial hypercholesterolemia is a condition characterized by very high levels of cholesterol in the blood due to genetic changes in the LDLR gene. People with hypercholesterolemia have a high risk of developing a form of heart disease called coronary artery disease, as well as health problems related to the buildup of excess cholesterol in other tissues (e.g., in the tendons and skin). Homozygous familial hypercholesterolemia tends to be passed through families in an autosomal dominant fashion. There are other hereditary forms of hypercholesterolemia caused by genetic changes in the APOB, LDLRAP1, or PCSK9 gene. However, most cases of high cholesterol are not caused by a single inherited condition, but result from a combination of lifestyle choices and the effects of variations in many genes.
Summary
Homozygous familial hypercholesterolemia is a condition characterized by very high levels of cholesterol in the blood due to genetic changes in the LDLR gene. People with hypercholesterolemia have a high risk of developing a form of heart disease called coronary artery disease, as well as health problems related to the buildup of excess cholesterol in other tissues (e.g., in the tendons and skin). Homozygous familial hypercholesterolemia tends to be passed through families in an autosomal dominant fashion. There are other hereditary forms of hypercholesterolemia caused by genetic changes in the APOB, LDLRAP1, or PCSK9 gene. However, most cases of high cholesterol are not caused by a single inherited condition, but result from a combination of lifestyle choices and the effects of variations in many genes.
Read More
Resource(s) for Medical Professionals and Scientists on This Disease:
  • RARe-SOURCE™  offers rare disease gene variant annotations and links to rare disease gene literature.
  • GeneReviews  provides clinical information on genetic diseases, including diagnosis, treatment, and genetic counseling.

About Homozygous familial hypercholesterolemia

Many rare diseases have limited information. Currently, GARD aims to provide the following information for this disease:

  • Population Estimate:Fewer than 5,000 people in the U.S. have thisdisease.
  • Symptoms:May start to appear as a Newborn.
  • Cause:This disease has more than one possible cause.
  • Organizations:Patient organizations are available to help find a specialist, or advocacy and support for this specific disease.
  • Categories:Inherited MetabolicdiseasesGeneticdiseasesEndocrinediseases

Causes

What Causes This Disease?

Genetic Mutations

Homozygous familial hypercholesterolemia is caused by genetic mutations, also known as pathogenic variants. Genetic mutations can be hereditary, when parents pass them down to their children, or they may occur randomly when cells are dividing. Genetic mutations may also result from contracted viruses, environmental factors, such as UV radiation from sunlight exposure, or a combination of any of these. Learn more about genetic diseases from the National Library of Medicine (NLM).

If you suspect you may have this disease, you may want to start collecting your family health history. Information such as other family members who have had similar symptoms, when their/your symptoms first appeared, or exposures to any potential disease-causing environmental factors should be discussed with your medical team. This tool from the Surgeon General can help you collect your family health history.

Can This Disease Be Passed Down From Parent to Child?

Yes. It is possible for a biological parent to pass down genetic mutations that cause or increase the chances of getting this disease to their child. This is known as inheritance. Knowing whether other family members have previously had this disease, also known as family health history, can be very important information for your medical team. This tool from the Surgeon General can help you collect your family health history.

There are multiple ways, or patterns, a disease can be inherited depending on the gene(s) involved. Based on GARD's current data, this disease can be inherited in the following pattern(s):

Autosomal Dominant

Autosomal means the gene involved is located on one of the numbered chromosomes. Dominant means that a child only needs to inherit one copy of the mutated gene, from either biological parent, to be affected by the disease.

People affected by an autosomal dominant disease have a 50% chance of passing on the mutated gene to their biological child.

Learn more about inheritance patterns from the National Library of Medicine (NLM).

When Do Symptoms of Homozygous familial hypercholesterolemia Begin?

Symptoms of this disease may start to appear as a Newborn.

The age symptoms may begin to appear differs between diseases. Symptoms may begin in a single age range, or during several age ranges. The symptoms of some diseases may begin at any age. Knowing when symptoms may have appeared can help medical providers find the correct diagnosis.
Prenatal
Before Birth
Newborn Selected
Birth-4 weeks
Infant
1-23 months
Child
2-11 years
Adolescent
12-18 years
Adult
19-65 years
Older Adult
65+ years
Symptoms may start to appear as a Newborn.
This information comes from Orphanet

Symptoms

The types of symptoms experienced, and their intensity, may vary among people with this disease. Your experience may be different from others. Consult your health care team for more information.

The following describes the symptom(s) associated with this disease along with the corresponding body system(s), description, synonyms, and frequency (Note: Not all possible symptoms may be listed):
Cardiovascular System Cardiovascular System

30 Symptoms

30 Symptoms

30 Symptoms

Cardiovascular System

The cardiovascular system is made up of the heart and blood vessels, including the arteries, veins, and capillaries. Common symptoms of problems in the cardiovascular system include high blood pressure, heart rate or heart rhythm problems, chest pain or discomfort, pain or tingling in the hands or feet, and fatigue. Diseases of the cardiovascular system may be diagnosed and treated by a cardiologist.
Medical Term

Precocious atherosclerosis

Frequency
Uncommon
Very frequent
Very frequent
Always
Synonym
Premature atherosclerosis
Open detail view
30 Symptoms
This information comes from the Human Phenotype Ontology (HPO)

Diagnostic Journey

On average, it takes more than six years to receive an accurate rare disease diagnosis. Many primary care providers (PCPs) may not be familiar with rare diseases, and you may need to see multiple specialists to reach the correct diagnosis. However, advocating for yourself with your healthcare team may help speed your time to diagnosis. To combat common challenges, be prepared:

  • Find disease-specific information to discuss with your healthcare providers.
  • Ask for diagnostic tests.
  • Request referrals to specialists.

Knowing where to start your diagnostic journey and how to navigate the next steps are critical to speeding your time to diagnosis

Your Diagnostic Team

How can a diagnostic team help?

Establishing care with a dedicated primary care provider (PCP) is an important early step in your rare disease journey. A PCP can help improve care and shorten the time to diagnosis by providing referrals to the appropriate specialists. These specialists, with advanced training in different body systems or types of diseases, can offer the specialized diagnostic procedures you need.

Use this tool by Medicare to find a PCP in your area by inputting your location and keyword "Primary Care Provider."

A PCP that specializes in the care of children is called a pediatrician. Use this tool by the American Academy of Pediatrics to find a pediatrician in your area by inputting your location.
Diagnostic teams for Homozygous familial hypercholesterolemia may include:
 

Multidisciplinary Care Centers

Is it time to find a multidisciplinary care center?

If you've visited your PCP, met with specialists, and undergone the recommended tests, but still do not have a confirmed diagnosis, it may be time to visit a multidisciplinary care center. Multidisciplinary care centers are usually teaching, university, or research hospitals that have teams of medical experts and specialists working together in the same location. This means a wide range of diagnostic tests and clinical knowledge are available at one facility, which can help increase communication and collaboration among your care team. The additional resources often available at multidisciplinary centers may help speed the time to diagnosis for rare diseases.



Multidisciplinary Care Centers

Is it time to find a multidisciplinary care center?

If you've visited your PCP, met with specialists, and undergone the recommended tests, but still do not have a confirmed diagnosis, it may be time to visit a multidisciplinary care center. Multidisciplinary care centers are usually teaching, university, or research hospitals that have teams of medical experts and specialists working together in the same location. This means a wide range of diagnostic tests and clinical knowledge are available at one facility, which can help increase communication and collaboration among your care team. The additional resources often available at multidisciplinary centers may help speed the time to diagnosis for rare diseases.



Rare Disease Experts

How can you find a rare disease expert?

If a diagnosis remains unknown despite extensive efforts by your PCP and specialists, it can be challenging to know what kind of expert you may need or where to find one. A rare disease expert is a care provider that has knowledge or training on specific disease(s), but there may only be a few experts in your state, region, or country. Rare disease experts may work at large research or teaching hospitals. In complex cases, coordinating with a network of experts can help your care provider find the right diagnosis. 
Contact a GARD Information Specialist for help finding an expert.

You can ask your care providers for help finding an expert or use directory tools to search for experts near you. The following organization(s) may maintain a list of experts or expert centers for people living with Homozygous familial hypercholesterolemia:

Rare Disease Experts

How can you find a rare disease expert?

If a diagnosis remains unknown despite extensive efforts by your PCP and specialists, it can be challenging to know what kind of expert you may need or where to find one. A rare disease expert is a care provider that has knowledge or training on specific disease(s), but there may only be a few experts in your state, region, or country. Rare disease experts may work at large research or teaching hospitals. In complex cases, coordinating with a network of experts can help your care provider find the right diagnosis. 
Contact a GARD Information Specialist for help finding an expert.

You can ask your care providers for help finding an expert or use directory tools to search for experts near you. The following organization(s) may maintain a list of experts or expert centers for people living with Homozygous familial hypercholesterolemia:
 

Find Your Community

How Can Patient Organizations Help?

Patient organizations can help patients and families connect. They build public awareness of the disease and are a driving force behind research to improve patients' lives. They may offer online and in-person resources to help people live well with their disease. Many collaborate with medical experts and researchers.

Services of patient organizations differ, but may include:

  • Ways to connect to others and share personal stories
  • Easy-to-read information
  • Up-to-date treatment and research information
  • Patient registries
  • Lists of specialists or specialty centers
  • Financial aid and travel resources

Please note: GARD provides organizations for informational purposes only and not as an endorsement of their services. Please contact an organization directly if you have questions about the information or resources it provides.

View GARD's criteria for including patient organizations, which can be found under the FAQs on our About page. Request an update or to have your organization added to GARD.

Patient Organizations

6 Organizations

Organization Name

Who They Serve

Helpful Links

Country

Family Heart Foundation
People With

Homozygous familial hypercholesterolemia

Helpful Links
Country

United States

Foundation of the National Lipid Association
People With

Homozygous familial hypercholesterolemia

Helpful Links
Country

United States

EveryLife Foundation for Rare Diseases
People With

Rare Diseases

Helpful Links
Country

United States

Genetic Alliance
People With

Rare Diseases

Helpful Links
Country

United States

Global Genes
People With

Rare Diseases

Helpful Links
Country

United States

National Organization for Rare Disorders
People With

Rare Diseases

Helpful Links
Country

United States

Participate in Research

Clinical studies are part of clinical research and play an important role in medical advances, including for rare diseases. Through clinical studies, researchers may ultimately uncover better ways to treat, prevent, diagnose, and understand human diseases.

What Are Clinical Studies?

Clinical studies are medical research involving people as participants. There are two main types of clinical studies:

  1. Clinical trials determine if a new test or treatment for a disease is effective and safe by comparing groups receiving different tests/treatments.
  2. Observational studies involve recording changes over time among a specific group of people in their natural settings.
Learn more about clinical trials from this U.S. Food & Drug Administration webpage.

Why Participate in Clinical Studies?

People participate in clinical trials for many reasons. People with a disease may participate to receive the newest possible treatment and additional care from clinical study staff as well as to help others living with the same or similar disease. Healthy volunteers may participate to help others and to contribute to moving science forward.

To find the right clinical study we recommend you consult your doctors, other trusted medical professionals, and patient organizations. Additionally, you can use ClinicalTrials.gov to search for clinical studies by disease, terms, or location.

What if There Are No Available Clinical Studies?

ResearchMatch helps connect people interested in research studies  with researchers from top medical centers across the United States. Anyone from the U.S. can register with this free program funded by NIH. Researchers from participating institutions use the database to search for and invite patients or healthy volunteers who meet their study criteria to participate.

Join the All of Us Research Program!

The All of Us Research Program is inviting 1 million people from all backgrounds across the U.S. to help build one of the most diverse health databases in history. Researchers will use the data to learn how our biology, lifestyle, and environment affect health. This may one day help them find ways to treat and prevent diseases.

What Are Clinical Studies?

Clinical studies are medical research involving people as participants. There are two main types of clinical studies:
  1. Clinical trials determine if a new test or treatment for a disease is effective and safe by comparing groups receiving different tests/treatments.
  2. Observational studies involve recording changes over time among a specific group of people in their natural settings.
Learn more about clinical trials from this U.S. Food & Drug Administration webpage.
Read More

Why Participate in Clinical Studies?

People participate in clinical trials for many reasons. People with a disease may participate to receive the newest possible treatment and additional care from clinical study staff as well as to help others living with the same or similar disease. Healthy volunteers may participate to help others and to contribute to moving science forward.

To find the right clinical study we recommend you consult your doctors, other trusted medical professionals, and patient organizations. Additionally, you can use ClinicalTrials.gov to search for clinical studies by disease, terms, or location.
Read More

What if There Are No Available Clinical Studies?

ResearchMatch helps connect people interested in research studies  with researchers from top medical centers across the United States. Anyone from the U.S. can register with this free program funded by NIH. Researchers from participating institutions use the database to search for and invite patients or healthy volunteers who meet their study criteria to participate.

Join the All of Us Research Program!

The All of Us Research Program is inviting 1 million people from all backgrounds across the U.S. to help build one of the most diverse health databases in history. Researchers will use the data to learn how our biology, lifestyle, and environment affect health. This may one day help them find ways to treat and prevent diseases.

ClinicalTrials.gov, an affiliate of NIH, provides current information on clinical research studies in the United States and abroad. Talk to a trusted doctor before choosing to participate in any clinical study. We recommend checking this site often and searching for studies with related terms/synonyms to improve results.
Search ClinicalTrials.gov for this disease
Contact a GARD Information Specialist if you need help finding more information on this rare disease or available clinical studies. Please note that GARD cannot enroll individuals in clinical studies.
1-888-205-2311
Available toll-free Monday through Friday from 12 pm to 6 pm Eastern Time
(Except: Federal Holidays)
Contact GARD
Use the contact form to send your questions to a GARD Information Specialist.

Please allow 2 to 10 business days for us to respond.
ClinicalTrials.gov, an affiliate of NIH, provides current information on clinical research studies in the United States and abroad. Talk to a trusted doctor before choosing to participate in any clinical study. We recommend checking this site often and searching for studies with related terms/synonyms to improve results.
Search ClinicalTrials.gov for this disease
Contact a GARD Information Specialist if you need help finding more information on this rare disease or available clinical studies. Please note that GARD cannot enroll individuals in clinical studies.
1-888-205-2311
Available toll-free Monday through Friday from 12 pm to 6 pm Eastern Time
(Except: Federal Holidays)
Contact GARD
Use the contact form to send your questions to a GARD Information Specialist.

Please allow 2 to 10 business days for us to respond.

Last Updated: December 2024