Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.9.3.1 (cytochrome oxidase)
 8,822 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A case of mitochondrial encephalomyopathy (Kearns-Sayre syndrome) with corneal endothelial abnormality is reported. A 22-year-old woman had retinitis pigmentosa, external ophthalmoplegia, complete heart block, ataxia, muscle weakness, dementia, sensorineural hearing loss, and was of short stature. Renal dysfunction, diabetes mellitus, and amenorrhea were also observed. Biopsy revealed decreased cytochrome c oxidase (complex IV) activity in muscle mitochondria. The corneal endothelium examined by specular microscope showed decreased cell density, severe polymegathism, and pleomorphism in both eyes. To our knowledge, this is the first report concerning primary corneal endothelial abnormality in a case with mitochondrial encephalomyopathy. The corneal endothelium is one of the tissues that could be affected by the enzyme deficiency present in this disease.
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PMID:Corneal endothelium in a case of mitochondrial encephalomyopathy (Kearns-Sayre syndrome). 274 82

Premature ovarian insufficiency (POI) is defined as the cessation of ovarian function under the age of 40 years and is characterized by amenorrhea, hypoestrogenism, and elevated serum gonadotrophin concentration (FSH). It is a heterogeneous disorder with a multicausal pathogenesis; however, majority of cases are idiopathic. In idiopathic POI, involvement of unknown mechanisms may increase rate of oocyte apoptosis. Studies have shown that elevated reactive oxygen species (ROS) levels affect the quality of gametes. Mitochondrial mutations in different complexes of electron transport chain have been reported to disrupt the electron flow which lead to formation of more superoxide ions or increased levels of ROS. This study was aimed to screen the mitochondrial genome for variations in idiopathic POI (n = 25) and occult ovarian insufficiency (OI) (n = 5) patients. 30 patients diagnosed with POI and occult OI were enrolled in this study. Blood samples were collected from the patients and controls. DNA was extracted using phenol chloroform method. A total of 102 nucleotide variations were observed in patients as compared with 58 nucleotide variations in controls. 24% variations were found to be non-synonymous and 76% were synonymous. It was found that 48% variations were in complex I, 8% in complex III, 24% in complex IV, and 20% in complex V of electron transport chain. We found most of the non-synonymous mitochondrial variations in complex I (48%) of the respiratory chain which is the largest enzyme complex and is associated with oxidative stress. Some non-synonymous pathogenic alterations (p.M31T, p.W239C, p.L128Q) and non pathogenic alterations (ATPase6:p.T53I, ATPase6:p.L190F, ATPase6:p.L199L) were found to be significantly higher in cases as compared with controls. The preliminary data suggest that the mitochondrial mutations and subsequent decline in ATP levels may accelerate follicular atresia and lead to POI. The results of this preliminary study highlight the need to extend this study by analyzing large number of samples in different ethnic populations and analyze for ROS levels and mitochondrial mutations in oocytes as they are of different embryonic origin and develop in a different microenvironment.
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PMID:Nucleotide variations in mitochondrial DNA and supra-physiological ROS levels in cytogenetically normal cases of premature ovarian insufficiency. 2068 Mar 10