Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0085584 (encephalopathy)
 18,178 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mitochondria is an intracellular double membrane-bound structure and it can provide energy for intracellular metabolism. The metabolism includes Krebs cycle, beta-oxidation and lipid synthesis. The density of mitochondria is different in various tissues dependent upon the demands of oxidative phosphorylation. Mitochondrial diseases can occur by defects either in mitochondrial DNA or nuclear DNA. Human mitochondrial DNA (mtDNA) encoding for 22 tRNAs, 2 rRNAs and 13 mRNAs that are translated in the mitochondria. Mitochondrial genetic diseases are most resulted from defects in the mtDNA which may be point mutations, deletions, or mitochondrial DNA depletion. These patterns of inheritance in mitochondrial diseases include sporadic, maternally inherited, or of Mendelian inheritance. Mitochondrial DNA depletion is caused by defects in the nuclear genes that are responsible for maintenance of integrity of mtDNA or deoxyribonucelotide pools and mtDNA biogenesis. The mtDNA depletion syndrome (MDS) includes the following categories: progressive external ophthalmoplegia (PEO), predominant myopathy, mitochondrial neurogastrointestinal encephalomyopathy (MNGIE), sensory-ataxic neuropathy, dysarthria, and ophthalmoplegia (SANDO) and hepato-encephalopathy. The most common tissues or organs involved in MDS and related disorders include the brain, liver and muscles. These involved genes are divided into two groups including 1) DNA polymerase gamma (POLG, POLG2) and Twinkle genes whose products function directly at the mtDNA replication fork, and 2) adenine nucleotide translocator 1, thymidine phosphorylase, thymidine kinase 2, deoxyguanosine kinase, ADP-forming succinyl-CoA synthetase ligase, MPV17 whose products supply the mitochondria with deoxyribonucleotide triphosphate pools needed for mtDNA replication, and possible mutation in the RRM2B gene. The development has provided new information about the importance of the biosynthetic pathway of the nucleotides for mtDNA replication. Further investigation on the understatanding between the nuclear and mitochondrial genomes is expected.
 ...
PMID:[Mitochondrial disease and mitochondrial DNA depletion syndromes]. 2032 99

Mitochondrial DNA depletion syndrome (MDS) is a group of disorders characterized by a quantitative reduction of the mitochondrial DNA copy number and inherited as autosomal recessive traits. Patients affected by this group of diseases present with a wide variety of symptoms depending on the altered gene. MPV17 is one of the genes causing combined encephalopathy and liver failure and at present there is no treatment for this devastating disease. The gene codes for an inner mitochondrial membrane protein, but its function is still unknown, and therefore, the only way to offer prenatal diagnosis relies on DNA studies. Consequently, mutations have to be well characterized. We previously described a patient homozygous for a novel intronic mutation in the MPV17 gene (c.70 + 5G > A). Here we report the use of a functional splicing assay based on the use of minigenes to support that c.70 + 5G > A mutation is disease causing. We carried out three prenatal diagnoses on three consecutive pregnancies of the previously described family. After two affected fetuses, a healthy baby was born homozygous for the wild-type allele.
 ...
PMID:Functional splicing assay supporting that c.70 + 5G > A mutation in the MPV17 gene is disease causing. 2061 88

Three deceased infants from a Pakistani consanguineous family presented with a similar phenotype of cholestatic liver disease, hypotonia, severe failure to thrive, recurrent vomiting, renal tubulopathy, and a progressive neurodegenerative course. Mitochondrial DNA depletion syndrome was considered in view of multisystem involvement. Exome sequencing, revealed a homozygous novel mutation c.1183T>C (p.F395L) in exon 1 of the C10orf2 TWINKLE gene. The hepatocerebral phenotype is well recognized in association with recessive mutations involving the C10orf2 TWINKLE gene. The feature of renal tubulopathy adds to the multisystemic presentation in our patients and further demonstrates an expansion of the phenotype in mitochondrial DNA depletion syndrome associated with TWINKLE gene mutations. The absence of features of an epileptic encephalopathy appears to be of added interest.
 ...
PMID:Exome sequencing reveals a homozygous mutation in TWINKLE as the cause of multisystemic failure including renal tubulopathy in three siblings. 2337 28

Mitochondrial DNA depletion consisting of the systemic reduction of mtDNA copy number in cells may have a heterogenous genetic basis, resulting from a pathogenic change in the nuclear genes involved in mtDNA synthesis. The mode of inheritance is autosomal recessive. Severe hepatocerebral disease represents one of many different clinical forms of so-called mitochondrial depletion syndrome (MDS). We present the liver histopathology of 13 children who eventually died in the course of hepatocerebral MDS confirmed molecularly, harbouring mutations of <i>DGUOK</i>, <i>MPV17</i>, and <i>POLG </i>genes. Material comprising eight autopsy and five liver biopsy specimens showed a moderately reproducible pattern of parenchymal damage, which we consider potentially helpful in the differential diagnosis and planning of the diagnostic investigation in families of children who died due to early-onset acute liver failure and encephalopathy.
 ...
PMID:Histopathological liver findings in patients with hepatocerebral mitochondrial depletion syndrome with defined molecular basis. 3050 56

Mitochondrial DNA depletion syndromes (MDS) are a group of clinically and genetically heterogeneous autosomal recessive disorders characterized by a reduction of mtDNA. We report two siblings of Armenian origin with early onset neurodegenerative disease characterized by encephalopathy, severe hypotonia, facial dyskinetic movements, abnormal eye movements, severe failure to thrive, and abnormal renal and hepatic function. Sanger sequencing confirmed two variants in the C10orf2 gene (TWNK) and indicated a diagnosis of MDS. Our recent observation confirms that nephrocalcinosis and proximal tubulopathy can be a part of a clinical picture of MDS associated with TWNK mutations and document peculiar ocular and orobuccolingual dyskinesias. Wrist myoclonia and tongue tremor were new clinical features in our patients. We suggest that the above-mentioned clinical constellation could potentially provide the basis for the diagnosis of MDS.
 ...
PMID:Expanding phenotype of mitochondrial depletion syndrome in association with TWNK mutations. 3079 93

Mitochondrial DNA depletion syndromes (MTDPS) are a group of rare genetic disorders caused by defects in multiple genes involved in mitochondrial DNA (mtDNA) maintenance. Among those, FBXL4 mutations result in the encephalomyopathic mtDNA depletion syndrome 13 (MTDPS13; OMIM #615471), which commonly presents as a combination of failure to thrive, neurodevelopmental delays, encephalopathy, hypotonia, and persistent lactic acidosis. We report here the case of a Lebanese infant presenting to us with profound neurodevelopmental delays, generalized hypotonia, facial dysmorphic features, and extreme emaciation. Whole-exome sequencing (WES) showed the girl as having MTDPS13 with an underlying FBXL4 missense mutation that has been previously reported only twice in unrelated individuals (c.1303C > T). Comprehensive literature search marked our patient as being the 94th case of MTDPS13 reported to date worldwide, and the first from Lebanon. We include at the end of this report a comprehensive mutation review table of all the pathological FBXL4 mutations reported in the literature, using it to highlight, for the first time, a possible founder effect of Arab origins to the disorder, being most prevalent in patients of Arab descent as shown in our mutation table. Finally, we provide a direct comparison of the disorder's clinical manifestations across two unrelated patients harboring the same disease-causing mutation as our patient, emphasizing the remarkable variability in genotype-to-phenotype correlation characteristic of the disease.
 ...
PMID:FBXL4-Related Mitochondrial DNA Depletion Syndrome 13 (MTDPS13): A Case Report With a Comprehensive Mutation Review. 3080 83