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Pearson syndrome
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Condition

Pearson syndrome

Pearson syndrome is a severe disorder that typically begins in infancy, affecting blood-forming cells in the bone marrow and the function of the pancreas and other organs, caused by large deletions in mitochondrial DNA.

Overview

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

Frequently Asked Questions

pproximately 20‑30 % of patients experience a “phenotypic shift” to Kearns‑Sayre syndrome or milder mitochondrial disease as the mutant mtDNA load declines in hematopoietic tissue. Survivors often develop progressive neuromuscular weakness, ophthalmoplegia, or cardiac conduction defects in later childhood or adolescence. Ongoing cardiac monitoring, audiology, and neuro‑developmental assessments are recommended.
Diagnosis relies on a combination of clinical findings (failure‑to‑thrive, anemia, neutropenia, pancreatic insufficiency) and laboratory confirmation of large mtDNA deletions. The gold standard is quantitative PCR or next‑generation sequencing of mitochondrial DNA from blood, bone‑marrow aspirate, or skin fibroblasts showing a heteroplasmic deletion >5 kb. Bone‑marrow smear showing vacuolated precursors and ring sideroblasts supports the diagnosis.
Yes. Pearson syndrome is caused by sporadic, large‑scale mtDNA deletions that are usually not inherited, so recurrence risk for future children is low (<1 %). However, maternal mtDNA heteroplasmy should be evaluated, and counseling includes discussion of mitochondrial donation techniques if a pathogenic deletion is detected in the mother’s oocytes.
Management is multidisciplinary: regular red‑cell transfusions to keep hemoglobin >8 g/dL, granulocyte‑colony stimulating factor (G‑CSF) for severe neutropenia, and platelet transfusions if bleeding risk is high. Pancreatic enzyme replacement (pancrelipase 500–1,000 U/kg with meals) and fat‑soluble vitamin supplementation (A, D, E, K) address exocrine insufficiency. Nutritional support (high‑calorie formula or gastrostomy) is often needed.
HSCT can correct the bone‑marrow failure component but does not eliminate the underlying mitochondrial DNA defect, so extra‑hematologic manifestations (e.g., pancreatic dysfunction, neuro‑developmental issues) usually persist. HSCT is considered only for severe, transfusion‑dependent cytopenias when the risk–benefit ratio is favorable.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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