title: Pearson syndrome: unique endocrine manifestations including neonatal diabetes and adrenal insufficiency.
abstract: OBJECTIVE
  Pearson syndrome is a very rare metabolic disorder that is usually present in infancy with transfusion dependent macrocytic anemia and multiorgan involvement including exocrine pancreas, liver and renal tubular defects. The disease is secondary to a mitochondrial DNA deletion that is variable in size and location. Endocrine abnormalities can develop, but are usually not part of the initial presentation. We report two patients who presented with unusual endocrine manifestations, neonatal diabetes and adrenal insufficiency, who were both later diagnosed with Pearson syndrome.
  
  
  METHODS
  Medical records were reviewed. Confirmatory testing included: mitochondrial DNA deletion testing and sequencing of the breakpoints, muscle biopsy, and bone marrow studies.
  
  
  RESULTS
  Case 1 presented with hyperglycemia requiring insulin at birth. She had several episodes of ketoacidosis triggered by stress and labile blood glucose control. Workup for genetic causes of neonatal diabetes was negative. She had transfusion dependent anemia and died at 24 months due to multisystem organ failure. Case 2 presented with adrenal insufficiency and anemia during inturcurrent illness, requiring steroid replacement since 37 months of age. He is currently 4 years old and has mild anemia. Mitochondrial DNA studies confirmed a 4.9 kb deletion in patient 1 and a 5.1 kb deletion in patient 2.
  
  
  CONCLUSIONS
  The patients reported highlight the importance of considering mitochondrial DNA disorders in patients with early onset endocrine dysfunction, and expand the knowledge about this rare mitochondrial disease.
authors.affiliation: Division of Metabolic Disorders, CHOC Children's, Orange, CA 92868, USA.
authors.forename: T B
authors.initials: TB
authors.lastname: Williams
authors.forename: M
authors.initials: M
authors.lastname: Daniels
authors.forename: G
authors.initials: G
authors.lastname: Puthenveetil
authors.forename: R
authors.initials: R
authors.lastname: Chang
authors.forename: R Y
authors.initials: RY
authors.lastname: Wang
authors.forename: J E
authors.initials: JE
authors.lastname: Abdenur
mesh_terms: D044942:Acyl-CoA Dehydrogenase, Long-Chain / Q000172:deficiency; D000309:Adrenal Insufficiency / Q000235:genetics / Q000473:pathology / Q000628:therapy; D000740:Anemia / Q000235:genetics / Q000473:pathology; D000756:Anemia, Sideroblastic / Q000150:complications / Q000235:genetics*; D001786:Blood Glucose / Q000235:genetics / Q000378:metabolism; D000080984:Congenital Bone Marrow Failure Syndromes; D004272:DNA, Mitochondrial / Q000235:genetics*; D002658:Developmental Disabilities / Q000378:metabolism / Q000473:pathology; D003920:Diabetes Mellitus / Q000235:genetics / Q000473:pathology / Q000628:therapy; D004703:Endocrine System / Q000473:pathology; D005260:Female; D020249:Hormone Replacement Therapy; D006801:Humans; D006943:Hyperglycemia / Q000378:metabolism / Q000473:pathology; D007231:Infant, Newborn; D007328:Insulin / Q000008:administration & dosage / Q000378:metabolism; D008052:Lipid Metabolism, Inborn Errors; D008297:Male; D028361:Mitochondrial Diseases / Q000150:complications / Q000235:genetics*; D009135:Muscular Diseases; D017384:Sequence Deletion / Q000235:genetics*
chemical_list: D001786:Blood Glucose; D004272:DNA, Mitochondrial; D007328:Insulin; D044942:Acyl-CoA Dehydrogenase, Long-Chain