Question: What is (are) Pearson syndrome ?
Answer: Pearson syndrome is a mitochondrial disorder characterized by transfusion-dependent sideroblastic anemia and pancreatic dysfunction resulting in in malabsorption and chronic diarrhea. The features of this progressive disorder may change over time. Individuals who survive beyond infancy often develop the symptoms of Kearns-Sayre syndrome or Leigh syndrome. Pearson syndrome is caused by deletions in mitochondrial DNA. Inheritance is usually sporadic.
Source: GARD

Question: What are the symptoms of Pearson syndrome ?
Answer: What are the signs and symptoms of Pearson syndrome? The Human Phenotype Ontology provides the following list of signs and symptoms for Pearson syndrome. If the information is available, the table below includes how often the symptom is seen in people with this condition. You can use the MedlinePlus Medical Dictionary to look up the definitions for these medical terms. Signs and Symptoms Approximate number of patients (when available) Abnormality of skin pigmentation 90% Abnormality of the heme biosynthetic pathway 90% Anemia 90% Delayed skeletal maturation 90% Exocrine pancreatic insufficiency 90% Intrauterine growth retardation 90% Malabsorption 90% Muscular hypotonia 90% Reduced bone mineral density 90% Type I diabetes mellitus 90% 3-Methylglutaric aciduria - Complex organic aciduria - Failure to thrive - Lactic acidosis - Metabolic acidosis - Mitochondrial inheritance - Pancreatic fibrosis - Refractory sideroblastic anemia - Renal Fanconi syndrome - Small for gestational age - The Human Phenotype Ontology (HPO) has collected information on how often a sign or symptom occurs in a condition. Much of this information comes from Orphanet, a European rare disease database. The frequency of a sign or symptom is usually listed as a rough estimate of the percentage of patients who have that feature. The frequency may also be listed as a fraction. The first number of the fraction is how many people had the symptom, and the second number is the total number of people who were examined in one study. For example, a frequency of 25/25 means that in a study of 25 people all patients were found to have that symptom. Because these frequencies are based on a specific study, the fractions may be different if another group of patients are examined. Sometimes, no information on frequency is available. In these cases, the sign or symptom may be rare or common.
Source: GARD