It is a mitochondrial deletion disorder which mostly affects the bone marrow and pancreas.
Half the children suffering from this syndrome die at the infant or early childhood stage in life because of liver failure or lactic acidosis.
The patients who survive this syndrome develop a condition of Kearns-Sayre syndrome later in their life. This condition causes the weakness of skeletal muscles and progressive external ophthalmoplegia.
History
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Howard Pearson, a pediatric hematologist and oncologist, first described the syndrome in 1979, after observing macrocytic anemia in four children, however, the deletions responsible for the condition were identified a decade later.
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Rotig et al. discovered a deletion 4,977 base pair long that spanned genes that code for 4 subunits of NADH dehydrogenase in mtDNA with the help of probes.
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Baerlocher et al. found a deletion of 5.5 kb mtDNA in an 8-year-old with Pearson syndrome from infancy, who later showed symptoms of Kearns-Sayre symptoms.
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Superti-Furga et al. revealed that Pearson syndrome is a multi-organ disorder and not only confined to bone marrow and pancreas. The phenotype, as well as the clinical course, is determined by portions of modified mtDNA molecules and tissue distribution.
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Casademont et al. came to a conclusion that the syndrome was autosomal dominant.
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Krauch et al. substantiated that weakening of cardiac function is also a major factor of Pearson syndrome.
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Shanske et al. observed through a case of a mother and her infant son that some single deletions could be transmitted through in germline, although, these are very rare and most deletions in mtDNA are sporadic.
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Jacobs et al. indicated that life expectancy is improved by duplications rather than dimerisations and result in less intense Kearns-Sayre symptoms phenotype.
