Pearson Syndrome

What is Pearson Syndrome?

Pearson syndrome is a mitochondrial DNA deletion syndrome with the onset in the first six months of life that primarily affects the bone marrow and the pancreas[1]. For this reason, it is sometimes called Pearson marrow-pancreas syndrome. Pearson syndrome is very rare; it affects an estimated 1 out of 1,000,000 individuals[2].

The disorder usually presents as a severe shortage of red blood cells between the ages of 0 and 31 months and progresses to impact the pancreas as well as other organs. Although the red blood cell shortage resolves in 2 out of 3 patients, the disease is severe[3]. Sadly, most individuals with Pearson syndrome die due to infections and organ failure before the age of 6[4]. Those who survive typically develop Kearns-Sayre syndrome (KSS).

Medical research has yet to identify a cure for Pearson syndrome. Current treatments focus on managing symptoms to improve an individual’s quality of life.

What causes Pearson Syndrome?

Pearson syndrome is caused by the deletion of a portion of the mitochondrial DNA[5]. The region of DNA that is deleted can vary. The most common deletion associated with Pearson syndrome removes 4,997 DNA building blocks (nucleotides) and has been found in 40-50% of affected individuals[4]. This deletion is the same that is most commonly associated with Kearn-Sayre syndrome.

The overwhelming majority of these deletions have appeared chanced novo, meaning this deletion is not found in the mother’s cells. Very rarely, a mutation that causes Pearson syndrome may be inherited from a mother with chronic progressive external ophthalmoplegia (CPEO)[4].

What are the symptoms of Pearson Syndrome?

The defining symptoms of Pearson syndrome are those that affect the bone marrow and pancreas. 

The symptoms that indicate diseased bone marrow include[6]:

  • low red blood cell count (anemia)
  • low white blood cell count (neutropenia)
  • low platelet count (thrombocytopenia)

Common symptoms experienced by individuals with Pearson syndrome that indicate a diseased pancreas include[4,6]:

  • frequent diarrhea
  • vomiting
  • trouble gaining weight (failure to thrive)

Individuals with Pearson syndrome may also have[4,6]:

  • high levels of lactic acid in the bloodstream
  • frequent severe infections
  • muscle weakness
  • short stature
  • liver disease
  • kidney disease
  • hormone deficiencies
  • diabetes
  • movement disorders
  • droopy eyelids (ptosis)
  • vision problems
  • heart disease

How do I know if my loved one has Pearson  Syndrome?

If your loved one has symptoms of Pearson syndrome, their healthcare provider may perform the following[4]:

  • a bone marrow sample (biopsy) 
  • a urine test
  • a stool test
  • genetic testing to look for mitochondrial DNA deletion 

What are the treatments for Pearson  Syndrome?

Treatments can help address some of the symptoms of Pearson syndrome. Options include[4,6]:

  • blood transfusions for anemia and medications to treat the iron overload that occurs with repeated blood transfusions
  • pancreatic enzyme replacement therapy for pancreas dysfunction
  • tube feeding for failure to thrive
  • sodium bicarbonate substitutions for high levels of lactic acid in the bloodstream
  • hormone replacement therapy for any deficient hormones
  • antibiotics for infections
  • physical therapy for muscle weakness
  • vitamins such as coenzyme Q10 or L-carnitine for general benefit (unproven)
  • surgery or special glasses to correct drooping eyelids
  • pacemaker for heart disease

Medications that are potentially toxic to mitochondria such as valproic acid, aminoglycosides, chloramphenicol, linezolid, and nucleoside reverse transcriptase inhibitors should be avoided[6]. Additionally, regular checkups with specialists help optimize care for individuals with Pearson syndrome and their families[4].


Are there any clinical trials for Pearson Syndrome?

To see what trials you may qualify for, visit our Clinical Trials page – which also includes a Clinical Trials Finder Tool. We also highly encourage you to join our patient registry, mitoSHARE, where we are actively recruiting Pearson syndrome families.

How can my family cope with Pearson  Syndrome?

We are here to help. UMDF serves many families coping with Pearson syndrome. We suggest you reach out to our Support & Education Team – online, via email at, or phone at (888) 900-6486 – who can suggest a host of resources including doctors, disease or region specific support meetings, and more. They’ll also connect you with a UMDF ambassador, who will be fellow Pearson syndrome patient or family member if possible, who can help support and guide you through your questions.

What are the next steps if my loved one has Pearson Syndrome?

  • Get Support
    Connect with our Support & Education Team online, via email at or phone at (888) 900-6486.
  • Check our Clinical Trials Finder
    Use our Clinical Trials Finder to see if you qualify for any clinical trials.
  • Join our patient registry, mitoSHARE
    We are actively recruiting Pearson syndrome families to participate in our patient registry, mitoSHARE. Patient registries like mitoSHARE are an integral part in charting a course toward treatments and cures for Pearson syndrome and other mitochondrial diseases. There are currently over 30 active mitochondrial disease clinical trials. Next generation patient registries like mitoSHARE are an integral part of expanding that number.
  • Become an advocate
    Ask your representatives to prioritize mitochondrial disease research and support via the UMDF Advocacy Center. We’ll send regular action items so you – and your friends and family – can let Congress know where we need their support. Click here to sign up.

What is UMDF doing about Pearson  Syndrome?

UMDF is helping chart a path toward treatments and eventual cure of mitochondrial diseases like Pearson syndrome through:

  • Research & Funding: UMDF has provided more than $15 million in research funding to find treatments for diseases like Pearson syndrome. UMDF advocacy has helped secure an additional $55 million in federal funding via the Department of Defense and National Institutes of Health.
  • Data: Over two decades ago, UMDF pioneered patient registries for the mitochondrial disease community. Today, our next generation patient registry, mitoSHARE, is helping chart a path toward the treatment and eventual cure of mitochondrial diseases.
  • Patient Support: Thousands of families just like you depend upon UMDF for support and education on diseases like Pearson syndrome. Attendance at our support meetings annually tops 7,000, including disease specific support meetings for families.
  • Clinician Support: To help educate clinicians on diseases like Pearson syndrome, we feature monthly Bench to Bedside clinician seminars, host the annual Mitochondrial Medicine Symposium, support the Mitochondrial Care Network, and educate clinicians on our Mito U platform.

Where can I find more information on Pearson  Syndrome?

I didn’t find what I’m looking for here. What should I do?

UMDF Is here to help. Contact the Support Line at (888) 900-6486 weekdays from 8:00am to 5:00pm EST to connect with our Patient Concierge. Or, via email contact


  1. Pearson HA, Lobel JS, Kocoshis SA, et al. A new syndrome of refractory sideroblastic anemia with vacuolization of marrow precursors and exocrine pancreatic dysfunction. J Pediatr. 1979;95(6):976-984. doi:10.1016/s0022-3476(79)80286-3
  1. Farruggia P, Di Cataldo A, Pinto RM, et al. Pearson Syndrome: A Retrospective Cohort Study from the Marrow Failure Study Group of A.I.E.O.P. (Associazione Italiana Emato-Oncologia Pediatrica). JIMD Rep. 2016;26:37-43. doi:10.1007/8904_2015_470
  1. Yoshimi A, Grünert SC, Cario H, et al. Haematological characteristics and spontaneous haematological recovery in Pearson syndrome. Br J Haematol. 2021;193(6):1283-1287. doi:10.1111/bjh.17434
  1. Yoshimi A, Ishikawa K, Niemeyer C, Grünert SC. Pearson syndrome: a multisystem mitochondrial disease with bone marrow failure. Orphanet J Rare Dis. 2022 Oct 17;17(1):379. doi: 10.1186/s13023-022-02538-9. PMID: 36253820; PMCID: PMC9575259.
  1. Rötig A, Colonna M, Blanche S, et al. Deletion of blood mitochondrial DNA in pancytopenia. Lancet. 1988;2(8610):567-568. doi:10.1016/s0140-6736(88)92687-6
  1. Goldstein A, Falk MJ. Mitochondrial DNA Deletion Syndromes. 2003 Dec 17 [Updated 2019 Jan 31]. In: Adam MP, Ardinger HH, Pagon RA, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2022. Available from: