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Mitochondrial Cytopathy Disease presenting in infancy as sideroblastic anemia, pancytopenia, defective oxidative phosphorylation, exocrine pancreatic insufficiency, and variable hepatic, renal, and endocrine failure. Death often occurs in infancy as a consequence of infection or metabolic crisis. Those who survive the first year of life present with Kearns-Sayre Syndrome (progressive mitochondrial disorder characterized by progressive external ophthalmoplegia and weakness of skeletal muscle).

Pearson Marrow-Pancreas Syndrome.

Originally described by Pearson et al. in 1979, the disorder involves the hematopoietic system (sideroblastic anemia with vacuolization of marrow precursors) and exocrine pancreatic dysfunction, as well as liver and kidney dysfunction.

Unknown; isolated case reports only.

The existence of an autosomal dominant mitochondrial DNA breakage syndrome is well established. There is mitochondrial DNA (mtDNA) deletion in a lymphoblastoid cell line in patients with Pearson Syndrome. Both sexes are affected.

This disease results from a defect of oxidative phosphorylation associated with deletions of the mitochondrial DNA. Severe, transfusion-dependent, macrocytic anemia starting in infancy may be associated with variable degree of neutropenia and thrombopenia. In addition there may be defects in liver (hepatic failure), kidney (proximal tubulopathy), gut (watery diarrhea), and skin (patchy erythematous lesions). High lactate/pyruvate molar ratios in plasma.

Pearson Syndrome resembles the Shwachman Syndrome in some ways in that bone marrow dysplasia and exocrine pancreas failure also occurs. However, the disorders differ in bone marrow morphology and Shwachman Syndrome also includes metaphysical chondrodysplasia. The bone marrow in patients with Pearson Syndrome is characterized by marked vacuolization of myeloid precursors and ringed sideroblasts and reduction in the size and number of the islets, fibrosis, and acinar atrophy of the pancreas. In addition, there is vacuolation of renal tubules, glomerulosclerosis, and “ragged red” fibers of skeletal muscles. mtDNA deletion is present in liver and skeletal muscle biopsies. In 1992, Gibson et al. detected 3-methylglutaconicaciduria in four patients with Pearson Syndrome and suggested that this finding may be a useful marker for Pearson Syndrome and more specific than other organic acids identified in this disorder. This disorder is fatal and few patients survive beyond a few years.

Typical hematologic symptoms (transfusion-dependent severe macrocytic anemia, neutropenia, thrombocytopenia) in early infancy. Insulin-dependent diabetes mellitus may develop during the course of the illness. There is failure to thrive secondary to exocrine pancreatic dysfunction and malabsorption. A few neonates with Pearson Syndrome have been reported to present with lactic acidosis. The tissue distribution and relative proportions of abnormal mtDNA molecules determine the phenotype and the clinical course. In general, the clinical course is progressive and death occurs in infancy. Some surviving patients later developed features of Kearns-Sayre Syndrome (another mtDNA deletion disorder with retinopathy, myopathy, and cardiac involvement), depending on the distribution of deleted mtDNA.

The diagnosis of mitochondrial disease should be considered in any child with a multisystem neurological disorder or who is being investigated for hypotonia. Anesthesia-related morbidity and mortality risk is ...

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