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)

We present the case of a 16-year-old boy with a family history of epilepsy who presented with acute respiratory failure, limb weakness, diabetes mellitus, sinus tachycardia, lactic acidosis, and pneumonia. He went on to develop cranial nerve palsy, myoclonus, generalized seizures, ataxia, recurrent pneumonia, and hypotension. Biochemical investigation revealed elevated lactate, pyruvate, and glucose levels. Cerebral magnetic resonance imaging (MRI) revealed bilateral, symmetric, high-intensity T2-weighted signals in the thalamus, brainstem, and gray matter of the spinal cord. Histochemical analyses revealed ragged red fibers (RRF) and decreased cytochrome oxidase activity. Blood and muscle-derived DNA demonstrated a high level (95% and 96%, respectively) of the m.8344A>G mutation, while almost all of his maternal relatives (n = 17, including his mother) carried the same point mutation. The point mutation level of his mother (who had short stature, high blood lactate levels, and epilepsy) was 77% (blood-derived DNA). Although this mutation has been identified in approximately 30 individuals with these disorders, to our knowledge, this is the first reported case of overlapping Leigh syndrome/myoclonic epilepsy with RRF in an adolescent patient, and the largest reported pedigree of mitochondrial DNA A8344G mutation.
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PMID:Overlapping Leigh Syndrome/Myoclonic Epilepsy With Ragged Red Fibres in an Adolescent Patient With a Mitochondrial DNA A8344G Mutation. 3027 74

Mutations in FASTKD2, a mitochondrial RNA binding protein, have been associated with mitochondrial encephalomyopathy with isolated complex IV deficiency. However, deficiencies related to other oxidative phosphorylation system (OXPHOS) complexes have not been reported. Here, we identified three novel FASTKD2 mutations, c.808_809insTTTCAGTTTTG, homoplasmic mutation c.868C>T, and heteroplasmic mutation c.1859delT/c.868C>T, in patients with mitochondrial encephalomyopathy. Cell-based complementation assay revealed that these three FASTKD2 mutations were pathogenic. Mitochondrial functional analysis revealed that mutations in FASTKD2 impaired the mitochondrial function in patient-derived lymphocytes due to the deficiency in multi-OXPHOS complexes, whereas mitochondrial complex II remained unaffected. Consistent results were also found in human primary muscle cell and zebrafish with knockdown of FASTKD2. Furthermore, we discovered that FASTKD2 mutation is not inherently associated with epileptic seizures, optic atrophy, and loss of visual function. Alternatively, a patient with FASTKD2 mutation can show sinus tachycardia and hypertrophic cardiomyopathy, which was partially confirmed in zebrafish with knockdown of FASTKD2. In conclusion, both in vivo and in vitro studies suggest that loss of function mutation in FASTKD2 is responsible for multi-OXPHOS complexes deficiency, and FASTKD2-associated mitochondrial disease has a high degree of clinical heterogenicity.
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PMID:Mutations in FASTKD2 are associated with mitochondrial disease with multi-OXPHOS deficiency. 3194 55