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Disease Information

Summary

Pearson syndrome is a severe disorder that usually begins in infancy. It causes problems with the development of blood-forming (hematopoietic) cells in the bone marrow that have the potential to develop into different types of blood cells. For this reason, Pearson syndrome is considered a bone marrow failure disorder. Function of the pancreas and other organs can also be affected. Most affected individuals have a shortage of red blood cells (anemia), which can cause pale skin (pallor), weakness, and fatigue. Some of these individuals also have low numbers of white blood cells (neutropenia) and platelets (thrombocytopenia). Neutropenia can lead to frequent infections; thrombocytopenia sometimes causes easy bruising and bleeding. When visualized under the microscope, bone marrow cells from affected individuals may appear abnormal. Often, early blood cells (hematopoietic precursors) have multiple fluid-filled pockets called vacuoles. In addition, red blood cells in the bone marrow can have an abnormal buildup of iron that appears as a ring of blue staining in the cell after treatment with certain dyes. These abnormal cells are called ring sideroblasts. In people with Pearson syndrome, the pancreas does not work as well as usual. The pancreas produces and releases enzymes that aid in the digestion of fats and proteins. Reduced function of this organ can lead to high levels of fats in the liver (liver steatosis). The pancreas also releases insulin, which helps maintain correct levels of blood glucose, also called blood sugar. A small number of individuals with Pearson syndrome develop diabetes, a condition characterized by abnormally high blood glucose levels that can be caused by a shortage of insulin. In addition, affected individuals may have scarring (fibrosis) in the pancreas. People with Pearson syndrome have a reduced ability to absorb nutrients from the diet (malabsorption), and most affected infants have an inability to grow and gain weight at the expected rate (failure to thrive). Another common occurrence in people with this condition is buildup in the body of a chemical called lactic acid (lactic acidosis), which can be life-threatening. In addition, liver and kidney problems can develop in people with this condition. Some people with Pearson syndrome have droopy eyelids (ptosis), vision problems, hearing loss, seizures, or movement disorders. About half of children with this severe disorder die in infancy or early childhood due to severe lactic acidosis or liver failure. Many of those who survive develop signs and symptoms later in life of a related disorder called Kearns-Sayre syndrome. This condition causes weakness of muscles around the eyes and other problems.

About Pearson syndrome

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

  • Symptoms:May start to appear from Birth to Childhood.
  • Cause:This disease has more than one possible cause.
  • Organizations:Patient organizations dedicated to this rare disease are available on GARD, or you may contact a GARD Information Specialist for additional information.
  • Categories:Genetic diseases(Genetic diseases affect the DNA, or genetic instructions, which directs how tissues, organs, and body systems function.)Endocrine diseases(Endocrine diseases affect hormone production or how the body responds to a specific hormone(s).)Gastrointestinal diseases(Gastrointestinal diseases, or digestive diseases, affect the esophagus, stomach, small intestine, large intestine, liver, gallbladder, or pancreas.)Blood diseases(Blood diseases affect the blood or blood-forming organs, including red blood cells, white blood cells, platelets, plasma, and bone marrow.)Inherited Metabolic diseases(Inherited metabolic diseases, or inborn errors of metabolism, are a group of genetic diseases that affect the ability of the body's cells to convert food into energy.)Mitochondrial diseases(Mitochondrial diseases are a group of genetic diseases that affect the ability of the body's cells to make energy.)

Resource(s) for Medical Professionals and Scientists on This Disease:

  • GeneReview provides clinical information on genetic diseases, including diagnosis, treatment, and genetic counseling.
  • MONDO provides GARD with information for this disease.
  • Orphanet provides GARD with information for this disease.

Resource(s) for Medical Professionals and Scientists on This Disease:

  • GeneReview provides clinical information on genetic diseases, including diagnosis, treatment, and genetic counseling.
  • MONDO provides GARD with information for this disease.
  • Orphanet provides GARD with information for this disease.

About Pearson syndrome

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

  • Symptoms:May start to appear from Birth to Childhood.
  • Cause:This disease has more than one possible cause.
  • Organizations:Patient organizations dedicated to this rare disease are available on GARD, or you may contact a GARD Information Specialist for additional information.
  • Categories:Genetic diseases(Genetic diseases affect the DNA, or genetic instructions, which directs how tissues, organs, and body systems function.)Endocrine diseases(Endocrine diseases affect hormone production or how the body responds to a specific hormone(s).)Gastrointestinal diseases(Gastrointestinal diseases, or digestive diseases, affect the esophagus, stomach, small intestine, large intestine, liver, gallbladder, or pancreas.)Blood diseases(Blood diseases affect the blood or blood-forming organs, including red blood cells, white blood cells, platelets, plasma, and bone marrow.)Inherited Metabolic diseases(Inherited metabolic diseases, or inborn errors of metabolism, are a group of genetic diseases that affect the ability of the body's cells to convert food into energy.)Mitochondrial diseases(Mitochondrial diseases are a group of genetic diseases that affect the ability of the body's cells to make energy.)

Causes

What Causes This Disease?

Genetic Mutations

Changes in your genes (also called variants) cause Pearson syndrome.

Genes are sections of DNA that contains instructions that help the body grow, develop, and function. A genetic variant is a change in your DNA's order. Parents may pass variants to their children, or they may occur randomly. They may result from viruses, environmental factors, such as UV radiation, or a combination of causes.

Most genetic variants do not cause disease. However, some can affect how a gene works and interfere with the body's normal functions. A pathogenic variant is one that causes disease.

If you think you may have this disease, collect your family health history (CDC). It may help you and your medical team to know about family members who have had the disease or similar symptoms and when those symptoms first appeared.

Read more about genetic disorders (NIH MedlinePlus). 

Genetic Mutations

Changes in your genes (also called variants) cause Pearson syndrome.

Genes are sections of DNA that contains instructions that help the body grow, develop, and function. A genetic variant is a change in your DNA's order. Parents may pass variants to their children, or they may occur randomly. They may result from viruses, environmental factors, such as UV radiation, or a combination of causes.

Most genetic variants do not cause disease. However, some can affect how a gene works and interfere with the body's normal functions. A pathogenic variant is one that causes disease.

If you think you may have this disease, collect your family health history (CDC). It may help you and your medical team to know about family members who have had the disease or similar symptoms and when those symptoms first appeared.

Read more about genetic disorders (NIH MedlinePlus). 

What causes disruption in metabolism?

Pearson syndrome is caused by a disruption in a person's metabolism. Metabolism is the series of chemical reactions in our body that turns the food we eat into energy and removes toxins. Hormones and specific proteins, called enzymes, help make the right chemical reactions happen in the right order. However, genetic changes can prevent hormones or enzymes from working properly, which can lead to a disruption in metabolism such as energy not being created for the body or toxins not being removed from the body. Learn more about inherited metabolic diseases from the National Human Genome Research Institute (NHGRI).

Impaired Mitochondrial Function

Pearson syndrome is caused by an impairment, or issue, in mitochondrial function. Mitochondria make the energy needed for cells to work properly. When mitochondria are unable to produce enough energy for a cell, the cell can become damaged or can die. Depending on the location and number of damaged cells, different organs and body systems can be affected. Learn more about mitochondrial diseases from the National Library of Medicine (NLM).

Can diseases be passed down from parent to child?

A biological parent can sometimes pass down genetic changes, called mutations, that cause a disease or increase the chances of developing it. This is called inheritance. Knowing if other family members have had the disease, also known as your family health history, can give your medical team important information. The Surgeon General offers a tool to help you collect your family health history.

What is mitochondrial DNA and how is it inherited?

Mitochondrial inheritance means the genetic mutation is located in a specific type of DNA, called mtDNA. mtDNA is found within the cell's mitochondria. Mitochondria are tiny structures that produce energy for the body. Genetic mutations within mtDNA can prevent the mitochondria from working properly.

During human conception, egg cells, or the cells that come from the female parent, provide mitochondria. If a female parent is affected by a mitochondrial genetic mutation, there is a 100% chance their child inherits the mutated gene. However, the child may or may not be affected by the disease. A male parent cannot pass mitochondrial genetic mutations to their children.

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

What is mitochondrial DNA and how is it inherited?

Mitochondrial inheritance means the genetic mutation is located in a specific type of DNA, called mtDNA. mtDNA is found within the cell's mitochondria. Mitochondria are tiny structures that produce energy for the body. Genetic mutations within mtDNA can prevent the mitochondria from working properly.

During human conception, egg cells, or the cells that come from the female parent, provide mitochondria. If a female parent is affected by a mitochondrial genetic mutation, there is a 100% chance their child inherits the mutated gene. However, the child may or may not be affected by the disease. A male parent cannot pass mitochondrial genetic mutations to their children.

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

When Do Symptoms of Pearson syndrome Begin?

Symptoms of this disease may start to appear from Birth to Childhood.

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.
  1. Prenatal
    Before Birth
  2. Newborn Selected
    Birth-4 weeks
  3. Infant Selected
    1-23 months
  4. Child Selected
    2-11 years
  5. Adolescent
    12-18 years
  6. Adult
    19-65 years
  7. Older Adult
    65+ years
Symptoms may start to appear from Birth to Childhood.
This information comes from Orphanet

Symptoms

You may have one or more symptoms, and they may be mild or severe. Having some or all of these symptoms does not mean you have this disease. Only a health care provider can diagnose you.

Common

Many people have these, but not everyone.

  • Abnormal bone marrow cell morphology
  • Abnormality of the heart (Abnormal heart morphology)
  • Abnormality of the nervous system
  • Bone marrow failure (Bone marrow hypocellularity)
  • Corneal stromal edema
  • Disease of the heart muscle (Cardiomyopathy)
  • Enlarged liver (Hepatomegaly)
  • Growth delay as children (Postnatal growth retardation)
  • Inability to properly digest food due to lack of pancreatic digestive enzymes (Exocrine pancreatic insufficiency)
  • Increased immature red blood cells (Reticulocytosis)
  • Increased spleen size (Splenomegaly)
  • Low blood neutrophil count (Decreased total neutrophil count)
  • Low number of red blood cells or hemoglobin (Anemia)
  • Low platelet count (Thrombocytopenia)
  • Renal failure (Renal insufficiency)
  • Severe infection
  • Small for gestational age

Uncommon

Some people have these, but most people do not.

  • Abnormality of the liver
  • Abnormally small skull (Microcephaly)
  • Adrenal insufficiency
  • Ataxia
  • Cafe-au-lait spot
  • Cardiac conduction abnormality
  • Central cleft palate (Median cleft palate)
  • Chronic diarrhea
  • Clouding of the lens of the eye (Cataract)
  • Decreased parathyroid hormone secretion (Hypoparathyroidism)
  • Decreased response to growth hormone stimulation test
  • Dehydration
  • Diabetes mellitus
  • Drooping upper eyelid (Ptosis)
  • Eye muscle paralysis (Ophthalmoplegia)
  • Fat in feces (Steatorrhea)
  • Global developmental delay
  • Growth delay
  • Hearing impairment
  • Hydrops fetalis
  • Involuntary, rapid, rhythmic eye movements (Nystagmus)
  • Kidney cyst (Renal cyst)
  • Liver failure (Hepatic failure)
  • Loss of developmental milestones (Developmental regression)
  • Low blood cell count (Pancytopenia)
  • Low muscle tone (Hypotonia)
  • Low muscle tone in trunk (Axial hypotonia)
  • Macronodular cirrhosis
  • Pancreatic fibrosis
  • Patchy darkened skin (Hyperpigmentation of the skin)
  • Photosensitive skin (Cutaneous photosensitivity)
  • Pigmentary retinopathy
  • Poor suck
  • Poor swallowing (Dysphagia)
  • Seizure
  • Underactive thyroid (Hypothyroidism)
  • Underdeveloped spleen (Hypoplastic spleen)
This information comes from the Human Phenotype Ontology (HPO)

Navigating Health Care Decisions

On average, it can take more than six years to receive an accurate diagnosis. Many primary care providers (PCPs) may not be familiar with rare diseases, and patients often need to visit multiple specialists or seek second opinions to get answers.

If a diagnosis remains unclear, visiting a multidisciplinary care center or university hospital may help. These centers bring together teams of specialists who can work together to evaluate symptoms and coordinate a diagnosis. This team-based approach is also helpful after a diagnosis, when managing care for rare diseases.

Because only about 5% of rare diseases have FDA-approved treatments, finding the right healthcare team to manage your symptoms and overall health is essential. People living with rare diseases often face challenges such as delayed diagnosis, limited treatment options, and difficulty accessing knowledgeable providers. Building a care team that understands your needs can make a significant difference in your quality of life.

Your Health Care Team

Why is building the right health care team important?

Building the right health care team is key to the diagnosis, treatment, and management of your long-term health journey living with a rare disease. Start by choosing a primary care provider (PCP). Your PCP will be your main point of contact and help coordinate care with other medical professionals. Your PCP may order tests or refer you to specialists. To find a PCP near you, use the Medicare provider search tool and enter your location and “Primary Care Provider.”

Seeing multiple specialists is important for people with rare diseases because these conditions often affect many parts of the body and require care from doctors with different expertise. Most primary care providers may not be familiar with rare diseases, so involving specialists can lead to a more accurate diagnosis and better care. A coordinated team approach ensures that all symptoms are addressed and that care is well-managed. It can also connect patients with the latest research or treatment options.

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.

These specialists may help in the diagnosis, management, and treatment of Pearson syndrome:

Hematologists are doctors with specialized training in diagnosing and treating diseases that affect the blood and bone marrow, where blood cells are produced. They also manage certain conditions of the lymphatic system, which includes the spleen and lymph tissues. Hematologists commonly care for people with anemia, bleeding or clotting disorders, and blood cancers such as leukemia and lymphoma. To diagnose these conditions, they may order blood tests or perform bone marrow biopsies.

You may want to consider bringing a copy of your medical history and a list of any medications to your appointment.

Ask your primary care provider for a referral or use this directory provided by the American Society of Hematology to find a specialist.
Gastroenterologists are doctors trained to diagnose and treat diseases that affect the digestive system, including the esophagus, stomach, intestines, pancreas, gallbladder, and liver. To evaluate digestive health, they may use flexible tubes with cameras called endoscopes to look inside the digestive tract. They treat conditions such as acid reflux, inflammatory bowel disease, liver disease, and digestive cancers. If you have ongoing digestive symptoms like abdominal pain, difficulty swallowing, or changes in bowel habits, a gastroenterologist can help find the cause and recommend treatment.

You may want to consider bringing a copy of your medical history and a list of any medications to your appointment.

Ask your primary care provider for a referral or use this directory provided by the American College of Gastroenterology to find a specialist.
Geneticists are doctors trained to diagnose and manage conditions caused by genetic changes, birth defects, or metabolic disorders. Metabolic disorders affect how the body makes or uses energy. Geneticists often work alongside genetic counselors to review family history, discuss genetic risks, explain testing options, and interpret genetic test results. They help people understand how inherited conditions may affect them and their families.

You may want to consider bringing a copy of your medical history and a list of any medications to your appointment.

Ask your primary care provider for a referral or use this directory provided by the American College of Medical Genetics and Genomics to find a specialist.
Endocrinologists are doctors trained to diagnose and manage diseases related to hormones. Hormones are chemical messengers that help coordinate many body functions, including metabolism, growth, and reproduction. Endocrinologists commonly treat conditions such as diabetes, thyroid disorders, and certain hormone-related cancers. They also care for people with concerns about growth or sexual development. Treatment options may include medications, hormone replacement therapy, or surgery, depending on the condition.

You may want to consider bringing a copy of your medical history and a list of any medications to your appointment.

Ask your primary care provider for a referral or use this directory provided by the Endocrine Society to find a specialist.

Multidisciplinary Care Centers

Is It Time to Get a Second Opinion or Specialized Evaluation?

If you've visited your PCP, met with specialists, and undergone the recommended tests, but are still searching for a diagnosis, it may be time to visit an academic medical center or, for pediatric patients, a children's hospital. Academic medical centers and children's hospitals, often called multidisciplinary care centers, typically bring together specialists from different fields to work together on complex cases like rare diseases.

Multidisciplinary care centers may offer more coordinated care and be involved in clinical research, which may help reduce the time to diagnosis and provide access to emerging diagnostic tools. Specialists at these centers may have a deeper understanding of rare diseases and serve as a resource when you'd like a second opinion, particularly when test results or treatment plans are not delivering expected results.

Find hospitals that may partner with medical schools and programs in your area. 

Children’s hospitals and large teaching hospitals may also offer dedicated specialists and programs for pediatric patients with undiagnosed or rare diseases. These programs bring pediatric experts together in one place and may provide more coordinated care for your child.

Search for children's or university hospitals in your area.

Rare Disease Experts

How can you find a rare disease expert?

If a diagnosis, care management, or treatment plan remains unclear despite extensive efforts by your PCP and specialists, it may be time to find a rare disease expert for your disease, if available. A rare disease expert is a medical provider that has knowledge or training on specific rare 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, sometimes called centers of excellence. Centers of Excellence commit to sharing knowledge and best practices that can lead to improved care and treatment for individuals living with a rare disease. 

You can also contact a GARD Information Specialist for help finding experts, centers of excellence, or clinics that focus on your disease.
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 Pearson syndrome:

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. Contact a GARD Information Specialist for more information on organizations that may be dedicated to this disease. 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 GARD page. Request an update or to have your organization added to GARD. 

Patient Organizations

4 Organizations

Muscular Dystrophy Association

People With

Pearson syndrome

Helpful Links
Country

United States

The Champ Foundation

People With

Pearson syndrome

Helpful Links
Country

United States

United Mitochondrial Disease Foundation

People With

Mitochondrial diseases

Helpful Links
Country

United States

MitoAction

People With

Mitochondrial diseases

Helpful Links
Country

United States

OrganizationPeople WithHelpful LinksCountry
Muscular Dystrophy AssociationPearson syndromeList of ExpertsUnited States
The Champ FoundationPearson syndromeResearch RegistryUnited States
United Mitochondrial Disease FoundationMitochondrial diseasesList of Experts
Research Registry		United States
MitoActionMitochondrial diseasesList of ExpertsUnited States

Participate in Research

Clinical studies are a part of clinical research and play an important role in medical advances 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 National Institutes of Health 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 a 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.

Why may you want to consider joining 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.
GARDGenetic and Rare Diseases
Information Center
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.
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Sources & References

Last Updated: September 2026