Analysis of ETFDH gene variation in a Chinese family affected with lipid storage myopathy / 中华医学遗传学杂志

OBJECTIVE@#To detect potential variation in an ethnic Han Chinese family affected with late-onset lipid storage myopathy.@*METHODS@#Next generation sequencing (NGS) was used to screen disease-related genes in the proband. Suspected mutation was validated with PCR and Sanger sequencing in two patients, their father, and 100 healthy controls.@*RESULTS@#Heterozygous c.770A>G (p.Tyr257Cys) and c.1395dupT (p.Gly466Tryfs) mutation were detected in the two patients. Their father was found to be heterozygous for the c.770A>G (p.Tyr257Cys) mutation, while the c.1395dupT (p.Gly466Tryfs) variation was not reported previously and not found among the healthy controls.@*CONCLUSION@#Mutations of the ETFDH gene probably underlie the pathogenesis in this family. The novel c.1395dupT (p.Gly466Tryfs) has enriched the mutation spectrum of EDFDH gene.

Clinical and muscle magnetic resonance image findings in patients with late-onset multiple acyl-CoA dehydrogenase deficiency / 中华医学杂志(英文版)

BACKGROUND@#Late-onset multiple acyl-coA dehydrogenase deficiency (MADD) is an autosomal recessive inherited metabolic disorder. It is still unclear about the muscle magnetic resonance image (MRI) pattern of the distal lower limb pre- and post-treatment in patients with late-onset MADD. This study described the clinical and genetic findings in a cohort of patients with late-onset MADD, and aimed to characterize the MRI pattern of the lower limbs.@*METHODS@#Clinical data were retrospectively collected from clinic centers of Peking University People's Hospital between February 2014 and February 2018. Muscle biopsy, blood acylcarnitines, and urine organic acids profiles, and genetic analysis were conducted to establish the diagnosis of MADD in 25 patients. Muscle MRI of the thigh and leg were performed in all patients before treatment. Eight patients received MRI re-examinations after treatment.@*RESULTS@#All patients presented with muscle weakness or exercise intolerance associated with variants in the electron transfer flavoprotein dehydrogenase gene. Muscle MRI showed a sign of both edema-like change and fat infiltration selectively involving in the soleus (SO) but sparing of the gastrocnemius (GA) in the leg. Similar sign of selective involvement of the biceps femoris longus (BFL) but sparing of the semitendinosus (ST) was observed in the thigh. The sensitivity and specificity of the combination of either "SO+/GA-" sign or "BFL+/ST-" sign for the diagnosis of late-onset MADD were 80.0% and 83.5%, respectively. Logistic regression model supported the findings. The edema-like change in the SO and BFL muscles were quickly recovered at 1 month after treatment, and the clinical symptom was also relieved.@*CONCLUSIONS@#This study expands the clinical and genetic spectrums of late-onset MADD. Muscle MRI shows a distinct pattern in the lower limb of patients with late-onset MADD. The dynamic change of edema-like change in the affected muscles might be a potential biomarker of treatment response.

A novel mutation in the ETFDH gene of an infant with multiple acyl-CoA dehydrogenase deficiency / 中国当代儿科杂志

This article reports the results of tandem mass spectrometry and the mutation features of the ETFDH gene for an infant with multiple acyl-CoA dehydrogenase deficiency. The results of tandem mass spectrometry showed that C14 : 1, C8, C6, C10, and C12 increased. Exon sequencing was performed on this infant and his parents and revealed double heterozygous mutations in the ETFDH gene of the infant: c.992A>T and c.1450T>C. The former was inherited from his mother, and the latter was inherited from his father. c.1450T>C was shown to be the pathogenic mutation in the HGMD database. PolyPhen2, SIFT, and PROVEAN all predicted that the novel mutation c.992A>T might be pathogenic, and the mutant amino acids were highly conserved across various species. The findings expand the mutation spectrum of the ETFDH gene, and provide molecular evidence for the etiological diagnosis of the patient with multiple acyl-CoA dehydrogenase deficiency as well as for the genetic counseling and prenatal diagnosis in the family.

Clinical features and ETFDH mutations of children with late-onset glutaric aciduria type II: a report of two cases / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To investigate the clinical and genetic features of two families with late-onset glutaric aciduria type II caused by ETFDH mutations.</p><p><b>METHODS</b>Target gene sequence capture and next generation sequencing were used for sequencing of suspected patients and their family members. The patients' clinical features were retrospectively analyzed and literature review was performed.</p><p><b>RESULTS</b>The probands of the two families had a clinical onset at the ages of 10 years and 5.5 years respectively, with the clinical manifestations of muscle weakness and muscle pain. Laboratory examinations revealed significant increases in the serum levels of creatine kinase, creatine kinase-MB, and lactate dehydrogenase. Tandem mass spectrometry showed increases in various types of acylcarnitines. The analysis of urine organic acids showed an increase in glutaric acid. Electromyography showed myogenic damage in both patients. Gene detection showed two novel mutations in the ETFDH gene (c.1331T>C from the mother and c.824C>T from the father) in patient 1, and the patient's younger brother carried the c.1331T>C mutation but had a normal phenotype. In patient 2, there was a novel mutation (c.177insT from the father) and a known mutation (c.1474T>C from the mother) in the ETFDH gene. Several family members carried such mutations. Both patients were diagnosed with glutaric aciduria type II. Their symptoms were improved after high-dose vitamin B2 treatment.</p><p><b>CONCLUSIONS</b>For patients with unexplained muscle weakness and pain, serum creatine kinase, acylcarnitines, and urinary organic acids should be measured, and the possibility of glutaric aciduria type II should be considered. Genetic detection is helpful to make a confirmed diagnosis.</p>

Clinical features and gene mutations in a patient with multiple aeyl-CoA dehydrogenase deficiency with severe fatty liver / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze the clinical features and gene mutations in an adolescent patient affected with late-onset multiple aeyl-CoA dehydrogenase deficiency (MADD) with severe fatty liver.</p><p><b>METHODS</b>Potential mutations of the ETFDH gene were detected with polymerase chain reaction (PCR) and DNA sequencing.</p><p><b>RESULTS</b>The 13-year-and-10-month girl has presented with weakness without any other special manifestation. Laboratory tests demonstrated an elevation of myocardial enzyme levels, total cholesterol, lactic acid and abnormal serum free fatty acids. H magnetic resonance spectroscopy revealed severe fatty liver. An increase in multiple plasma acyl-carnitines was detected by gas chromatography/mass spectrometry and isobutyrylglycine in urine by screening with tandem mass spectrometry. Genetic analysis demonstrated 2 heterozygous missense mutations c.250G>A (p.Ala84Thr) and c.353G>T (p.Cys118Phe) in the ETFDH gene. The diagnosis of MADD was confirmed. The patient was given large dose of vitamin B2, which resulted in rapid clinical and biochemical improvement.</p><p><b>CONCLUSION</b>A common mutation c.250G>A and a novel mutation c.353G>T in the ETFDH gene were identified in the patient. The pathogenic role of c.353G>T (p.Cys118Phe) deserves further study. Early diagnosis of MADD and appropriate therapy is crucial for the prognosis.</p>

Mutation analysis for a family affected with riboflavin responsive-multiple acyl-CoA dehydrogenase deficiency / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To identify pathogenic mutation in a boy affected with riboflavin responsive-multiple acyl-CoA dehydrogenase deficiency (RR-MADD).</p><p><b>METHODS</b>The patient was initially diagnosed as primary carnitine deficiency (PCD) and has been treated with carnitine supplementation for 7 years. Clinical manifestations and characteristics of fibula muscle specimen were analyzed. Potential mutation in electron transfer flavoprotein dehydrogenase (ETFDH) gene (for the patient and his parents) and carnitine transfer protein gene (SLC22A5) (for the patient) was screened.</p><p><b>RESULTS</b>Electronic microscopy of the muscle specimen has suggested lipid storage myopathy. Mutation analysis has found that the patient carried compound heterozygous mutations, c.250G>A and c.380T>C, in exon 3 of the ETFDH gene, whilst his father and mother were heterozygous for the c.380T>C and c.250G>A mutations, respectively. Screening of the SLC22A5 gene has yielded no clinically meaningful result. After the establishment of diagnosis of RR-MADD, the condition of the patient has improved greatly with supplementation of high doses of riboflavin along with continuous carnitine supplement.</p><p><b>CONCLUSION</b>The c.250G>A (p.Ala84Thr) mutation of exon 3 of the ETFDH gene has been a hot spot in Southern Chinese population, whilst the c.380T>C (p.Leu127Pro) is rarely reported. Our case has suggested that therapeutic diagnosis cannot substitute genetic testing. The mechanism for having stabilized the patient with only carnitine supplementation for 7 years needs further investigation.</p>

Association between gene polymorphisms of methylenetetrahydrofolate reductase and plasma homocysteine in Uygur patients with venous thromboembolism / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate methylenetetrahydrofolate reductase (MTHFR) gene C677T mutation and plasma homocysteine (Hcy) levels in Uygur patients with venous thromboembolism (VTE) in Xinjiang.</p><p><b>METHODS</b>A total of 222 VTE patients including 74 Uygur and 148 Han ethnic patients were examined, and 86 Uygur ethnic and Han 134 ethnic healthy people were included as controls. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was applied to detect MTHFR gene C677T polymorphism and plasma Hcy levels were measured by fluorescence polarization immunoassay.</p><p><b>RESULTS</b>The MTHFR gene C677T genotypes distribution in Uygur VTE patients and control groups were: TT [28.38% (35/86) vs. 12.79% (11/86), P < 0.05], CT [41.89% (31/74) vs. 52.33% (45/86), P > 0.05]and CC [29.73% (22/74) vs. 34.88% (30/86), P > 0.05], respectively; and in Han VTE patients and control groups were: TT[27.03% (40/148) vs. 14.92% (20/134), P < 0.05], CT [44.59% (66/148) vs. 52.99% (71/134), P > 0.05] and CC [28.38% (42/148) vs. 32.09% (43/134), P > 0.05], respectively. SNP genotyping distribution frequency in Uygur and Han ethnic population was similar between controls and between VTE patients (P > 0.05). Plasma levels of Hcy in MTHFR gene TT genotype were statistically higher than CT and CC genotype (P < 0.05). After adjusting for age, gender, smoking history, hyperlipidemia, hypertension, diabetes, and MTHFR genotype, multifactor logistic regression analysis showed that plasma Hcy level (OR = 1.025, 95%CI 1.003 - 1.046, P = 0.024) and obesity (OR = 4.660, 95%CI 1.417 - 15.324, P = 0.011) were independent risk factors for Uygur ethnic patients with VTE while plasma Hcy level (OR = 1.020, 95%CI 1.006 - 1.034, P = 0.004) and smoking (OR = 2.867, 95%CI 1.062 - 6.586, P = 0.024) were independent risk factors for Han ethnic patients with VTE.</p><p><b>CONCLUSION</b>MTHFR C677T polymorphism (TT genotype carrier) and increased plasma levels of Hcy are risk factors for Uygur and Han ethnic patients with VTE in Xinjiang.</p>

Advancement of methanol poisoning mechanism research / 法医学杂志

The methanol poisoning by oral intake or skin contact occurs occasionally, which may have serious consequences including blindness and/or death. Methanol and its metabolites, formaldehyde and formic acid, are associated with metabolic acidosis, visual dysfunction and neurological symptoms. At present, the mechanism of methanol poisoning primarily focuses on the cell hypoxia, the alteration of structure and biological activity induced by free radical and lactic acid. Meanwhile, methanol poisoning causes changes in the balance between the production of free radicals and antioxidant capacity and in the proteases-protease inhibitors system, which lead to a series of disturbances.

Highly expressed N1-acetylpolyamine oxidase detoxifies polyamine analogue N1-cyclopropylmethyl-N11-ethylnorspermine in human lung cancer cell line A549 / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The critical roles of polyamines in cell growth and differentiation have made polyamine metabolic pathway a promising target for antitumor therapy. Recent studies have demonstrated in vitro that some antitumor polyamine analogues could be used as substrates and oxidized by purified recombinant human N(1)-acetylpolyamine oxidase (APAO, an enzyme that catabolizes natural polyamines), indicating a potential role of APAO in determining the sensitivity of cancer cells to specific antitumor analogues. This study evaluated, in vivo, the effect of APAO on cytotoxicity of antitumor polyamine analogue, N(1)-cyclopropylmethyl-N(11)-ethylnorspermine (CPENS) and its mechanism when highly expressed in human lung cancer line A549.</p><p><b>METHODS</b>A clone with high expression of APAO was obtained by transfecting A549 lung cancer cell line with pcDNA3.1/APAO plasmid and selecting with quantitative realtime PCR and APAO activity assay. Cell proliferation was determined by MTT method and apoptosis related events were evaluated by DNA fragmentation, sub-G1/flow cytometric assay, western blotting (for cytochrome C and Bax) and colorimetric assay (for casapse-3 activity).</p><p><b>RESULTS</b>A clone highly expressing APAO was obtained. High expression of APAO in A549 cells inhibited accumulation of CPENS, decreased their sensitivity to the toxicity of CPENS and prevented CPENS induced apoptosis.</p><p><b>CONCLUSION</b>These results indicate a new drug resisting, mechanism in the tumor cells. High expression of APAO can greatly decrease the sensitivity of tumor cells to the specific polyamine analogues by detoxifying those analogues and prevent analogue induced apoptosis.</p>

In vitro inhibition of 10-formyltetrahydrofolate dehydrogenase activity by acetaldehyde

Alcoholism has been associated with folate deficiency in humans and laboratory animals. Previous study showed that ethanol feeding reduces the dehydrogenase and hydrolase activity of 10-formyltetrahydrofolate dehydrogenase (FDH) in rat liver. Hepatic ethanol metabolism generates acetaldehyde and acetate. The mechanisms by which ethanol and its metabolites produce toxicity within the liver cells are unknown. We purified FDH from rat liver and investigated the effect of ethanol, acetaldehyde and acetate on the enzyme in vitro. Hepatic FDH activity was not reduced by ethanol or acetate directly. However, acetaldehyde was observed to reduce the dehydrogenase activity of FDH in a dose- and time-dependent manner with an apparent IC50 of 4 mM, while the hydrolase activity of FDH was not affected by acetaldehyde in vitro. These results suggest that the inhibition of hepatic FDH dehydrogenase activity induced by acetadehyde may play a role in ethanol toxicity.

Pleiotropic effect of tatC mutation on metabolism of pathogen Yersinia enterocolitica / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To analyze the impact of depletion of the twin arginine translocation (TAT) system on virulence and physiology of Yersinia enterocolitica for a better understanding of its pathogenicity.</p><p><b>METHODS</b>We constructed a DeltatatC::SpR mutant of Yersinia enterocolitica by P1 phage mediated transduction using Escherichia coli K-12 DeltatatC::SpR strain as a donor.</p><p><b>RESULTS</b>A P1-mediated genetic material transfer was found between the two species of enterobacteria, indicating a great potential of acquisition of antibiotic resistance in emergency of a new threatening pathogen by genetic material exchanges. Periplasmic trimethylamine N-oxidase reductase activity was detected in the wild type Y. enterocolitica strain and translocation of this enzyme was completely abolished by the DeltatatC::SpR mutation. In addition, the DeltatatC::SpR mutation showed a pleiotropic effect on the metabolism of Y. enterocolitica. However, the tat mutation did not seem to affect the mobility and virulence of Y. enterocolitica under the conditions used.</p><p><b>CONCLUSION</b>Unlike other pathogenic bacteria studied, the TAT system of Y. enterocolitica might play an important role in the pathogenic process, which is distinct from other pathogens, such as Pseudomonas aeruginosa and enterohemorrhagic E. coli O157:H7.</p>

Changes and significance of PAO activities and polyamine levels at different time of reperfusion after transient focal cerebral ischemia in rats / 中南大学学报(医学版)

OBJECTIVE@#To assay the changes of polyamine oxidase (PAO) activities and polyamine levels in the cortex and subcortex at different time of reperfusion following 2 h focal cerebral ischemia in rats in order to explore the regularity and signifiance ofh these changes.@*METHODS@#Rats of 2 h reversible focal cerebral ischemia were produced by ameliorated method of Longa's intraluminal suture occlusion of middle cerebral artery (MCA). PAO activities and polyamine levels in the cortex and subcortex were measured by homovanillic acid fluorometry and high-performance liquid chromatograph (HPLC) after 2, 4, 8, and 24 h reperfusion following 2 h ischemia, respectively.@*RESULTS@#PAO activity of the experimental group increased after 8 h reperfusion (P < 0.01). The peak value of PAO activity appeared after 24 h reperfusion (P < 0.01). Putrescine level of the experimental group was elevated after 4 h reperfusion (P < 0.05), and the peak value of putrescine appeared after 24 h reperfusion (P < 0.05). Spermidine and spermine levels of 8, 24 h reperfusion in the experiment group decreased significantly c eompared with the control group (P < 0.05).@*CONCLUSION@#PAO activities increased significantly after reperfusion following transient focal cerebral ischemia, which promoted the later peak production of putrescine. It may be contributed to the brain damage after cerebral ischemia.

Alterações no metabolismo da homocisteína induzidas por aguardente de cana-de-açúcar em alcoólatras / Homocystein metabolism alterations induced by sugar-cane liquor in alcoholics

O alcoolismo está relacionado a má nutriçäo e baixos níveis de várias vitaminas que fazem parte do metabolismo da homocisteína (Hci). O objetivo deste estudo foi analisar a prevalência de hiper-homocisteinemia em pacientes com alta ingestäo diária de aguardente de cana-de-açúcar. Foram incluídos neste estudo 31 homens hospitalizados para tratamento de alcoolismo. Hci, folato (Fol), vitamina B12 séricos e enzimas hepáticas foram determinados e repetidos após 21 dias de abstinência alcoólica. Os valores de Hci em æmol/l antes e depois do tratamento foram, respectivamente, de 24,88 ± 2,09 e 12,48 ± 0,69. A abstinência alcoólica diminuiu significativamente os valores de aspartato aminotransferase, alanina aminotransferase e gamaglutamiltranspeptidase. Näo houve alteraçäo dos níveis de hemácias, proteínas totais e concentraçäo de hemoglobina corpuscular média. Os níveis de Hci antes do tratamento se correlacionaram com os de folato (r² = 0,333). Estes resultados sugerem que o alcoolismo crônico está acompanhado por perturbaçäo do metabolismo de aminoácidos sulfurados e que a hiper-homocisteinemia etanol-induzida através de aguardente de cana-de-açúcar pode ser acompanhada de níveis séricos baixos de folato, agravando o estado nutricional destes pacientes

Gene polymorphism and folate metabolism: a maternal risk factor for Down syndrome.

The high birth frequency of Down syndrome (DS), trisomy 21 (T21), has been a subject of interest to the clinicians and researchers due to its complexity in phenotypic expression. In addition to the maternal age, identification of the mechanistic basis for T21 requires an understanding of the cellular-molecular events and other biochemical pathways that could promote maternal meiotic nondisjunction. Recent studies have linked the increased frequency of polymorphism of methylenetetrahydrofolate reductase (MTHFR, C677T) and methionine synthase gene (MTRR, A66G) in mothers with DS child. Based on evidence that abnormal folate and methyl metabolism can lead to DNA hypomethylation and abnormal chromosomal segregation, researchers have observed that mothers with mutation in MTHFR (C677T) and MTRR (A66G) gene have elevated levels of plasma homocysteine. This was found to be associated with a 2.6 to 2.9 fold increased risk of having child with DS compared to mothers without the mutation. Subsequent studies evaluating Italian, Irish, French, and Indian-Gujarati women could not demonstrate an association of MTHFR gene polymorphism in mothers with DS child. However, the Irish study did find an increased risk of DS associated with the MTRR polymorphism and an interactive effect of MTRR and MTHFR polymorphisms with increased risk. Interestingly, an increase in plasma homocysteine was found to be a risk factor for DS in several of the studies. Despite the differences, the published studies suggest a common theme of abnormal folate metabolism associated with increased risk of having a child with DS. These observations suggest that there seems to be a geographic variation in gene polymorphism and it could not be attributable to meiotic nondysjunction in all mothers with DS child but increased homocysteine in all different study group does suggest that there may be a gene-nutritional or gene-gene or gene-nutritional-environmental factors involved in increased frequency of meiotic nondisjunction which needs transnational and multinational study design.

The relationship between MTHFR gene polymorphisms, plasma homocysteine levels and diabetic retinopathy in type 2 diabetes mellitus / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>To evaluate the role of methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms and plasma homocysteine levels in patients with type 2 diabetes mellitus and diabetic retinopathy (DR).</p><p><b>METHODS</b>Total of 208 patients with type 2 diabetes mellitus and 57 controls were recruited into the study. MTHFR genetic C677T polymorphisms were determined by PCR-RFLP. Plasma total homocysteine levels were measured using high-performance liquid chromatography (HPLC) with fluorescence detection.</p><p><b>RESULTS</b>The frequencies of MTHFR TT homogeneous type, CT heterogeneous type and allele T (28.18%, 41.82%, 49.09%) were significantly higher in the type 2 diabetes mellitus with diabetic retinopathy group than those without retinopathy (18.37%, 29.59%, 33.16%) and those of controls (17.54%, 28.07%, 31.58%). The presence of the T allele appeared to have a strong association with the development of diabetic retinopathy. The odds ratio was 1.94 with a 95% confidence interval of 1.31 - 2.88. Moreover, plasma homocysteine levels were remarkably higher in patients with TT or CT genotype than in patients with the CC genotype.</p><p><b>CONCLUSION</b>MTHFR gene C677T mutation associated with a predisposition to increased plasma homocysteine levels may be considered as a genetic risk factor for diabetic microangiopathy (such as DR) in Chinese patients with type 2 diabetes mellitus.</p>

The relationship of methylenetetrahydrofolate reductase gene polymorphism and plasma homocysteine levels in type 2 diabetes mellitus patients with diabetic retinopathy / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To evaluate the role of methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms and plasma homocysteine levels in Chinese patients with type 2 diabetes mellitus and diabetic retinopathy (DR).</p><p><b>METHODS</b>MTHFR genetic C677T polymorphisms were determined by PCR-restriction fragment length polymorphism. Total plasma homocysteine levels were measured using high-performance liquid chromatography (HPLC) with fluorescence detection.</p><p><b>RESULTS</b>The frequencies of MTHFR T homogenetic type and CT heterogenetic type and allele T (28.18%, 41.82%, 49.09%) in type 2 diabetic patients with diabetic retinopathy were significantly higher than those in diabetic patients without retinopathy (18.37%,29.59%,33.16%) or the normal controls (17.54%, 28.07%, 31.58%). Howerver, there were no significant differences in the frequency of MTHFR genotype and allele between the type 2 diabetic patients without retinopathy and the normal controls. The presence of T allele appeared to have a strong association with the development of diabetic retinopathy. The odds ratio was 1.94 and the 95% confidence interval was 1.31-2.88. Moreover, the plasma homocysteine levels in patients with TT or CT genotype were markedly higher than those in patients with CC genotype.</p><p><b>CONCLUSION</b>MTHFR gene C677T mutation associated with a predisposition to increase of plasma homocysteine may represent a genetic risk factor for diabetic retinopathy in Chinese type 2 diabetes mellitus.</p>

Protein kinase CK2 phosphorylates and interacts with deoxyhypusine synthase in HeLa cells

Deoxyhypusine is a modified lysine and formed posttranslationally to be the eukaryotic initiation factor eIF5A by deoxyhypusine synthase, employing spermidine as butylamine donor. Subsequent hydroxylation of this deoxyhypusine-containing intermediate completes the maturation of eIF5A. The previous report showed that deoxyhypusine synthase was phosphorylated by PKC in vivo and the association of deoxyhypusine synthase with PKC in CHO cells was PMA-, and Ca(2+)/phospholipid-dependent. We have extended study on the phosphorylation of deoxyhypusine synthase by protein kinase CK2 in order to define its role on the regulation of eIF5A in the cell. The results showed that deoxyhypusine synthase was phosphorylated by CK2 in vivo as well as in vitro. Endogenous CK2 in HeLa cells and the cell lysate was able to phosphorylate deoxyhypusine synthase and this modification is enhanced or decreased by the addition of CK2 effectors such as polylysine, heparin, and poly(Glu, Tyr) 4:1. Phosphoamino acid analysis of this enzyme revealed that deoxyhypusine synthase is mainly phosphorylated on threonine residue and less intensely on serine. These results suggest that phosphorylation of deoxyhypusine synthase is CK2-dependent cellular event as well as PKC-mediated effect. However, there were no observable changes in enzyme activity between the phosphorylated and unphosphorylated forms of deoxyhypusine synthase. Taken together, besides its established function in hypusine modification involving eIF5A substrate, deoxyhypusine synthase and its phosphorylation modification may have other independent cellular functions because of versatile roles of deoxyhypusine synthase.

Mutaçöes no gene da metilenotetrahidrofolato redutase e síndrome de Down / Mutations in the methylene-tetrahydrofolate reductase gene and Down syndrome

Sindrome de Down (SD) é uma alteraçäo genética e metabólica complexa atribuída à presença de três cópias do cromossomo 21. O cromossomo extra em 93 por cento dos casos é de origem materna e é resultante de uma segregaçäo anormal durante a meiose (näo-disjunçäo). Com exceçäo da idade materna avançada, fatores de risco para a näo-disjunçäo meiótica näo estäo bem estabelecidos. Um estudo preliminar sugeriu que o metabolismo anormal do folato e a mutaçäo 677 (C->T) no gene da metilenotetrahidrofolato redutase (MTHFR) podem ser fatores de risco maternos para a SD. A freqüência das mutaçöes MTHFR 677 (C->T) e 1.298 (A->C) foram avaliadas em 36 mäes de crianças com SD e em 200 indivíduos-controle. Os resultados demonstraram que as mutaçöes 677 (C->T) e 1.298 (A->C) säo mais prevalentes entre mäes de crianças com SD do que nos controles. A heterozigose das duas mutaçöes foi a combinaçäo mais freqüente. O resultado desse estudo inicial sugere que mutaçöes no gene da MTHFR seriam um fator de risco para a SD

Methylene tetrahydrofolate reductase gene mutation together with anticardiolipin antibody during pregnancy: a case report

CONTEXT: High plasmatic homocysteine levels have been associated with arterial and venous thrombosis. The C677T methylene tetrahydrofolate reductase (MTHFR) gene mutation is one of the known causes for high homocysteine levels in plasma. Anticardiolipin antibody (ACA) is also associated with thrombosis and, along with other clinical complications such as recurrent abortion and stillbirth, is part of the antiphospholipid syndrome. DESIGN: Case report. CASE REPORT: A 19-year-old woman with two gestations and one parity (G2P1) had exhibited deep venous thrombosis in her previous puerperal period. Investigation of thrombophilic factors revealed ACA-IgM and heterozygous C677T mutation in the MTHFR gene. Lupus anticoagulant, protein C, protein S and antithrombin III deficiencies, and Leiden factor V and the G20210A mutation in the prothrombin gene, were not detected. The patient received 55,000 IU of subcutaneous heparin daily, from the 15th to the 36th week of pregnancy, when vaginal delivery took place. There were no clinical complications during the puerperal period and she was discharged three days after delivery, while still using oral anticoagulants

Methylenetetrahydrofolate reductase gene mutation and hyperhomocysteinemia as a risk factor for coronary heart disease in the Indian population.

OBJECTIVE: The screening and therapeutic guidelines for the management of lipid abnormalities are reasonably well established. However, other risk factors like hyperhomocysteinemia (HCA) and single nucleotide polymorphisms involving the angiotensin converting enzyme (ACE) and angiotensinogen genes, various clotting factors etc., have yet to be established firmly as other causative factors of atherothrombotic disease. Our study was aimed at finding the relationship between HCA, folate, vitamins B12 levels, and mutations in the 5,10-methylenetetrahydrofolate reductase (MTHFR) and cystathionine beta-synthase (CBS) genes. METHODS: We studied 230 subjects, which included patients with angiographically documented coronary heart disease (CHD) (n=115) and controls (n=115) with no history of CHD. RESULTS: Elevated levels of plasma homocysteine, above 18 nmoles/ml, were detected in 19.13% and 18.26% of our patients and controls, respectively. Homocysteine was significantly correlated to Apo A1 (r=0.51, p < 0.05) and Apo B (r=0.49, p < 0.05). The heterozygous MTHFR mutation was found to be 54.5% (12/22) in our patients with HCA. Of these, 31.8% (7/22) were deficient for plasma folate. Heterozygosity for T833C mutation in the CBS gene was observed in 9.99% (2/22) of our patients with HCA. Both these patients were also deficient for plasma folate and vitamin B12. CONCLUSION: In our study, heterozygosity for the thermolabile MTHFR mutation was found to be associated with hyperhomocysteinemia (HCA). This genetic predisposition to HCA could be risk factor for CHD and can be correlated with vitamin supplementation. To the best of our knowledge this is the first report from India on plasma homocysteine levels and its genetic aspect in patients with CHD.