Mutations in CYC1, encoding cytochrome c1 subunit of respiratory chain complex III, cause insulin-responsive hyperglycemia.

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Citation

Gaignard P, Menezes M, Schiff M, Bayot A, Rak M, Ogier de Baulny H, Su CH, Gilleron M, Lombes A, Abida H, Tzagoloff A, Riley L, Cooper ST, Mina K, Sivadorai P, Davis MR, Allcock RJ, Kresoje N, Laing NG, Thorburn DR, Slama A, Christodoulou J, Rustin P

Mutations in CYC1, encoding cytochrome c1 subunit of respiratory chain complex III, cause insulin-responsive hyperglycemia.

Am J Hum Genet. 2013 Aug 8;93(2):384-9. doi: 10.1016/j.ajhg.2013.06.015. Epub 2013 Aug 1.

PubMed ID
23910460 [ View in PubMed
]
Abstract

Many individuals with abnormalities of mitochondrial respiratory chain complex III remain genetically undefined. Here, we report mutations (c.288G>T [p.Trp96Cys] and c.643C>T [p.Leu215Phe]) in CYC1, encoding the cytochrome c1 subunit of complex III, in two unrelated children presenting with recurrent episodes of ketoacidosis and insulin-responsive hyperglycemia. Cytochrome c1, the heme-containing component of complex III, mediates the transfer of electrons from the Rieske iron-sulfur protein to cytochrome c. Cytochrome c1 is present at reduced levels in the skeletal muscle and skin fibroblasts of affected individuals. Moreover, studies on yeast mutants and affected individuals' fibroblasts have shown that exogenous expression of wild-type CYC1 rescues complex III activity, demonstrating the deleterious effect of each mutation on cytochrome c1 stability and complex III activity.

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Polypeptides
NameUniProt ID
Cytochrome c1, heme protein, mitochondrialP08574Details