We report a 12-year-old patient with growth retardation, exercise intolerance, lactic acidosis (increasing after exercise) and autoimmune polyendocrinopathy type 2. Muscle biopsy shows abundant COX-negative fibers, subsarcolemmal mitochondrial aggregates and markedly reduced activities of all respiratory chain complexes. Genetic analysis identified two new cosegregating mutations in Met-tRNA (m.4415A>G) and Cox III (m.9922A>C), located in highly conserved regions of MtDNA. Both the mutations are heteroplasmics in multiple patients' tissues. Single-muscle fiber analysis showed significantly higher levels of both the mutations in COX-negative than in normal fibers. In addition, a possible link between the mitochondrial dysfunction and the autoimmune disease is suggested.
Two novel cosegregating mutations in tRNAMetand COX III, in a patient with exercise intolerance and autoimmune polyendocrinopathy / Bortot, B.; Barbi, E.; Biffi, S.; Angelini, C.; Faleschini, E.; Severini, G. M.; Carrozzi, M.. - In: MITOCHONDRION. - ISSN 1567-7249. - STAMPA. - 9:2(2009), pp. 123-129. [10.1016/j.mito.2009.01.006]
Two novel cosegregating mutations in tRNAMetand COX III, in a patient with exercise intolerance and autoimmune polyendocrinopathy
Barbi, E.;Biffi, S.;Carrozzi, M.
2009-01-01
Abstract
We report a 12-year-old patient with growth retardation, exercise intolerance, lactic acidosis (increasing after exercise) and autoimmune polyendocrinopathy type 2. Muscle biopsy shows abundant COX-negative fibers, subsarcolemmal mitochondrial aggregates and markedly reduced activities of all respiratory chain complexes. Genetic analysis identified two new cosegregating mutations in Met-tRNA (m.4415A>G) and Cox III (m.9922A>C), located in highly conserved regions of MtDNA. Both the mutations are heteroplasmics in multiple patients' tissues. Single-muscle fiber analysis showed significantly higher levels of both the mutations in COX-negative than in normal fibers. In addition, a possible link between the mitochondrial dysfunction and the autoimmune disease is suggested.Pubblicazioni consigliate
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