Novel Missense Mitochondrial ND4L Gene Mutations in Friedreich's Ataxia

AbstractObjective(s)The mitochondrial defects in Friedreich's ataxia have been reported in many researches. Mitochondrial DNA is one of the candidates for defects in mitochondrion, and complex I is the first and one of the largest catalytic complexes of oxidative phosphorylation (OXPHOS) system. Materials and MethodsWe searched the mitochondrial ND4L gene for mutations by TTGE and sequencing on 30 FRDA patients and 35 healthy controls.ResultsWe found 3 missense mutations [m.10506A>G (T13A), m.10530G>A (V21M), and m.10653G>A (A62T)] in four patients whose m.10530G>A and m.10653G>A were not reported previously. In two patients, heteroplasmic m.10530G>A mutation was detected. They showed a very early ataxia syndrome. Our results showed that the number of mutations in FRDA patients was higher than that in the control cases (P= 0.0287).ConclusionAlthough this disease is due to nuclear gene mutation, the presence of these mutations might be responsible for further mitochondrial defects and the increase of the gravity of the disease. Thus, it should be considered in patients with this disorder

Novel Point Mutations in Frataxin Gene in Iranian Patients with Friedreich’s Ataxia

How to Cite This Article: Heidari MM , Khatami M, Pourakrami J. Novel Point Mutations in Frataxin Gene in Iranian Patients withFriedreich’s Ataxia. Iran J Child Neurol. 2014 Winter; 8(1):32-36. ObjectiveFriedreich’s ataxia is the most common form of hereditary ataxia with autosomal recessive pattern. More than 96% of patients are homozygous for GAA repeat extension on both alleles in the first intron of FXN gene and the remainingpatients have been shown to be heterozygous for a GAA extension in one allele and point mutation in other allele.Materials & MethodsIn this study, exons of 1, 2, 3, and 5 of frataxin gene were searched by single strand conformation polymorphism polymerase chain reaction (PCR-SSCP) in 5 patients with GAA extension in one allele. For detection of exact mutation,samples with band shifts were sent for DNA sequencing.Results Three novel point mutations were found in patients heterozygous for the GAA repeat expansion, p.S81A, p.Y123D, and p.S192C. ConclusionOur results showed that these point mutations in one allele with GAA extension in another allele are associated with FRDA signs. Thus, these results emphasize the importance of performing molecular genetic analysis for point mutations inFRDA patients. References:Delatycki MB, Williamson R, Forrest SM. Friedreich ataxia: an overview. J Med Genet 2000;37(1):1-8.Harding AE, Zilkha KJ. ‘Pseudo-dominant’ inheritance in Friedreich’s ataxia. J Med Genet 1981;18(4):285-7.Schulz JB, Boesch S, Burk K, Durr A, Giunti P, Mariotti C, et al. Diagnosis and treatment of Friedreich ataxia: a European perspective. Nat Rev Neurol 2009;5(4):222-34.Campuzano V, Montermini L, Lutz Y, Cova L, Hindelang C, Jiralerspong S, et al. Frataxin is reduced in Friedreich ataxia patients and is associated with mitochondrial membranes. Hum Mol Genet 1997;6(11):1771-80.Sharma R, De Biase I, Gomez M, Delatycki MB, Ashizawa T, Bidichandani SI. Friedreich ataxia in carriers of unstable borderline GAA triplet-repeat alleles. Ann Neurol 2004;56(6):898-901.Durr A, Cossee M, Agid Y, Campuzano V, Mignard C, Penet C, et al. Clinical and genetic abnormalities in patients with Friedreich’s ataxia. N Engl J Med 1996;17;335(16):1169-75.Filla A, De Michele G, Cavalcanti F, Pianese L, Monticelli A, Campanella G, et al. The relationship between trinucleotide (GAA) repeat length and clinical features in Friedreich ataxia. Am J Hum Genet 1996;59(3):554-60.Lamont PJ, Davis MB, Wood NW. Identification and sizing of the GAA trinucleotide repeat expansion of Friedreich’s ataxia in 56 patients. Clinical and genetic correlates. Brain 1997;120 ( Pt 4):673-80.Montermini L, Richter A, Morgan K, Justice CM, Julien D, Castellotti B, et al. Phenotypic variability in Friedreich ataxia: role of the associated GAA triplet repeat expansion. Ann Neurol 1997;41(5):675-82.Monros E, Molto MD, Martinez F, Canizares J, Blanca J, Vilchez JJ, et al. Phenotype correlation and intergenerational dynamics of the Friedreich ataxia GAA trinucleotide repeat. Am J Hum Genet 1997;61(1):101-10.Zuhlke CH, Dalski A, Habeck M, Straube K, Hedrich K, Hoeltzenbein M, et al. Extension of the mutation spectrum in Friedreich’s ataxia: detection of an exon deletion and novel missense mutations. Eur J Hum Genet 2004;12(11):979-82.Heidari MM, Houshmand M, Hosseinkhani S, Nafissi S, Scheiber-Mojdehkar B, Khatami M. A novel mitochondrial heteroplasmic C13806A point mutation associated with Iranian Friedreich’s ataxia. Cell Mol Neurobiol 2009;29(2):225-33.Heidari MM, Houshmand M, Hosseinkhani S, Nafissi S, Scheiber-Mojdehkar B, Khatami M. Association between trinucleotide CAG repeats of the DNA polymerase gene (POLG) with age of onset of Iranian Friedreich’s ataxia patients. Neurol Sci 2008; 29(6):489-93.Heidari MM, Houshmand M, Hosseinkhani S, Nafissi S, Khatami M. Complex I and ATP content deficiency in lymphocytes from Friedreich’s ataxia. Can J Neurol Sci 2009;36(1):26-31.Campuzano V, Montermini L, Molto MD, Pianese L, Cossee M, Cavalcanti F, et al. Friedreich’s ataxia: autosomal recessive disease caused by an intronic GAA triplet repeat expansion. Science 1996;271(5254):1423-7.Sambrook J, Russel DW. Chapter 13: Detection of Mutations by Single-strand Conformational Polymorphism and Heteroduplex Analysis. Molecular cloning: a laboratory manual. 3eded. New York: Cold Spring Harborn Laboratory Press; 2001. P.49-59.Kyte J, Doolittle RF. A simple method for displaying the hydropathic character of a protein. J Mol Biol 1982;157(1):105-32.Harding AE, Hewer RL. The heart disease of Friedreich’s ataxia: a clinical and electrocardiographic study of 115 patients, with an analysis of serial electrocardiographic changes in 30 cases. Q J Med 1983;52(208):489-502.Cavalier L, Ouahchi K, Kayden HJ, Di Donato S, Reutenauer L, Mandel JL, et al. Ataxia with isolated vitamin E deficiency: heterogeneity of mutations and phenotypic variability in a large number of families. Am J Hum Genet 1998;62(2):301-10.Anheim M, Mariani LL, Calvas P, Cheuret E, Zagnoli F, Odent S, et al. Exonic deletions of FXN and early-onset Friedreich ataxia. Arch Neurol 2012;69(7):912-6.Li H, Gakh O, Smith DYt, Ranatunga WK, Isaya G. Missense mutations linked to friedreich ataxia have different but synergistic effects on mitochondrial frataxin isoforms. J Biol Chem 2013;288(6):4116-27.Evans-Galea MV, Corben LA, Hasell J, Galea CA, Fahey MC, du Sart D, et al. A novel deletion-insertion mutation identified in exon 3 of FXN in two siblings with a severe Friedreich ataxia phenotype. Neurogenetics 2011;12(4):307-13.

The POLG Polyglutamine Tract Variants in Iranian Patients with Multiple Sclerosis

How to Cite This Article: Khatami M, Heidari MM, Mansouri R, Mousavi F. The POLG Polyglutamine Tract Variants in Iranian Patients with Multiple Sclerosis. Iran J Child Neurol. 2015 Winter; 9(1):37-41.AbstractObjectiveMultiple Sclerosis (MS) is a common disease of the central nervous system. The interaction between inflammatory and neurodegenerative processes typically results in irregular neurological disturbances followed by progressive disability.Mitochondrial dysfunction has been implicated in neurodegenerative disorders. The DNA polymerase-gamma (POLG) gene, which encodes the catalytic subunit of enzyme responsible for directing mtDNA replication, contains a poly glutamine tract (poly-Q) in the N-terminal, encoded by a CAG sequence in exon 2.Materials & MethodsWe analyzed the POLG trinucleotide repeats in 40 Iranian patients with MS (27 females and 13 males with an age range of 18–55); and 47 healthy age, gender, and ethnic matched controls were chosen by PCR-SSCP analysis. ResultsOur results indicated that the most common allele in patients had 10 consecutive CAG repeats (10Q). Other alleles of 11and 12 trinucleotide repeats were detected.We did not find any difference between the CAG repeat length distribution in controls and MS patients.ConclusionNo correlation was observed in the POLG gene CAG repeat with pathogenesis of MS, but it looks that other point mutations in POLG gene may have an important role in the disease’s pathogenesis and produced more significant results.ReferencesBaranzini SE. Revealing the genetic basis of multiple sclerosis: are we there yet? Curr Opin Genet Dev. 2011 Jun; 21(3):317-24.Hoffjan S, Akkad DA. The genetics of multiple sclerosis: an update 2010. Mol Cell Probes. 2010 Oct; 24(5):237-43.Disanto G, Berlanga AJ, Handel AE, Para AE, Burrell AM, Fries A, et al. Heterogeneity in multiple sclerosis: scratching the surface of a complex disease. Autoimmune Dis. 2010; 2011:932351.International Multiple Sclerosis Genetics C, Wellcome Trust Case Control C, Sawcer S, Hellenthal G, Pirinen M, Spencer CC, et al. Genetic risk and a primary role for cell-mediated immune mechanisms in multiple sclerosis. Nature. 2011 Aug 11; 476(7359):214-9.Mao P, Reddy PH. Is multiple sclerosis a mitochondrial disease? Biochimica et biophysica acta. 2010 Jan; 1802(1):66-79.Inarrea P, Alarcia R, Alava MA, Capablo JL, Casanova A, Iniguez C, et al. Mitochondrial complex enzyme activities and cytochrome C expression changes in multiple sclerosis. Mol Neurobiol. 2014 Feb; 49(1):1-9.Schaller A, Hahn D, Jackson CB, Kern I, Chardot C, Belli DC, et al. Molecular and biochemical characterization of a novel mutation in POLG associated with Alpers syndrome. BMC Neurology. 2011; 11(1):4.Milone M, Brunetti-Pierri N, Tang LY, Kumar N, Mezei MM, Josephs K, et al. Sensory ataxic neuropathy with ophthalmoparesis caused by POLG mutations. Neuromuscul Disord. 2008 Aug; 18(8):626-32.Azrak S, Ayyasamy V, Zirpoli G, Ambrosone C, Bandera EV, Bovbjerg DH, et al. CAG repeat variants in the POLG1 gene encoding mtDNA polymerase-gamma and risk of breast cancer in African-American women. PLoS One. 2012; 7(1):e29548.Eerola J, Luoma PT, Peuralinna T, Scholz S, Paisan-Ruiz C, Suomalainen A, et al. POLG1 polyglutamine tract variants associated with Parkinson’s disease. Neurosci Lett. 2010 Jun 14; 477(1):1-5.Rovio A, Abel J, Ahola A, Andres A, Bertranpetit J, Blancher A, et al. A prevalent POLG CAG microsatellite length allele in humans and African great apes. Mammalian genome. 2004; 15(6):492-502.Spelbrink JN, Toivonen JM, Hakkaart GA, Kurkela JM, Cooper HM, Lehtinen SK, et al. In vivo functional analysis of the human mitochondrial DNA polymerase POLG expressed in cultured human cells. Journal of Biological Chemistry. 2000; 275(32):24818-28.Williams AJ, Paulson HL. Polyglutamine neurodegeneration: protein misfolding revisited. Trends in neurosciences. 2008; 31(10):521-8.Luoma P, Eerola J, Ahola S, Hakonen A, Hellström O, Kivistö K, et al. Mitochondrial DNA polymerase gamma variants in idiopathic sporadic Parkinson disease. Neurology. 2007; 69(11):1152-9.Heidari MM, Houshmand M, Hosseinkhani S, Nafissi S, Scheiber-Mojdehkar B, Khatami M. Association between trinucleotide CAG repeats of the DNA polymerase gene (POLG) with age of onset of Iranian Friedreich’s ataxia patients. Neurol Sci. 2008 Dec; 29(6):489-93.Heidari MM, Khatami M, Talebi AR. The POLG Gene Polymorphism in Iranian Varicocele-Associated Infertility Patients. Iran J Basic Med Sci. 2012 Mar; 15(2):739-44.Jensen M, Leffers H, Petersen JH, Nyboe Andersen A, Jorgensen N, Carlsen E, et al. Frequent polymorphism of the mitochondrial DNA polymerase gamma gene (POLG) in patients with normal spermiograms and unexplained subfertility. Hum Reprod. 2004 Jan; 19(1):65-70.Taanman JW, Schapira AH. Analysis of the trinucleotide CAG repeat from the DNA polymerase gamma gene (POLG) in patients with Parkinson’s disease. Neurosci Lett. 2005 Mar 7; 376(1):56-9.Wong LJ, Naviaux RK, Brunetti-Pierri N, Zhang Q, Schmitt ES, Truong C, et al. Molecular and clinical genetics of mitochondrial diseases due to POLG mutations. Hum Mutat. 2008 Sep; 29(9):E150-72.Kumleh HH, Riazi GH, Houshmand M, Sanati MH, Gharagozli K, Shafa M. Complex I deficiency in Persian multiple sclerosis patients. Journal of the Neurological Sciences. 2006 4/15/; 243(1–2):65-9.Ebers GC, Sadovnick AD, Dyment DA, Yee IML, Willer CJ, Risch N. Parent-of-origin effect in multiple sclerosis: observations in half-siblings. The Lancet. 2004; 363(9423):1773-4.Harding A, Sweeney M, Miller D, Mumford C, Kellar-Wood H, Menard D, et al. Occurrence of a multiple sclerosis-like illness in women who have a Leber’s hereditary optic neuropathy mitochondrial DNA mutation. Brain: a journal of neurology.1992; 115(4):979-89.Ahari SE, Houshmand M, Panahi MS, Kasraie S, Moin M, Bahar MA. Investigation on mitochondrial tRNA (Leu/Lys), NDI and ATPase 6/8 in Iranian multiple sclerosis patients. Cell Mol Neurobiol. 2007 Sep; 27(6):695-700.Mahad DJ, Ziabreva I, Campbell G, Lax N, White K, Hanson PS, et al. Mitochondrial changes within axons in multiple sclerosis. Brain: a journal of neurology. 2009 May; 132(Pt 5):1161-74

Increased Prevalence 12308 A > G mutation in Mitochondrial tRNALeu (CUN) Gene Associated with earlier Age of Onset in Friedreich Ataxia

How to Cite this Article: Heidari MM, Khatami M, Houshmand M, Mahmoudi E, Nafissi Sh .Increased Prevalence 12308 A > G mutation in MitochondrialtRNALeu (CUN) Gene Associated with earlier Age of Onset in Friedreich Ataxia. Iranian Journal of Child Neurology 2011;5(4):25-31.Objective Friedreich ataxia (FRDA) is an inherited recessive disorder. Mitochondrial DNA is a candidate modifying factor for FRDA.The purpose of this study was to investigate the relationship between the tRNALeu (CUN) 12308 A> G mutation and age of onset in Friedreich ataxia.Materials & Methods The 12308 A> G substitution in mitochondrial tRNALeu (CUN) was examined in DNA samples from 30 Friedreich ataxia patients and 48 control subjects by temporal temperature gradient gel electrophoresis (TTGE) and sequencing. Logistic regression was used to determine of cutoff age of onset.ResultsTwenty-two patients had the 12308 A> G mutation, and we found that its overall prevalence was significantly higher in 20 patients aged 17 years or younger than in 2 patients aged over 17 years (90% versus 10%). The 12308 A> G mutation lies in a region that has been highly conserved between species.Conclusion Our results show that the 12308 A > G mutation is associated with earlier age of onset in Friedreich ataxia. Thus, this mutation might cause the younger age of onset in FRDA.References Grabczyk E, Usdin K. The GAA*TTC triplet repeat expanded in Friedreich ataxia impedes transcription elongation by T7 RNA polymerase in a length and supercoil dependent manner. Nucleic Acids Res 2000;28(14):2815-22.Sakamoto N, Chastain PD, Parniewski P, Ohshima K, Pandolfo M, Griffith JD, et al. Sticky DNA: self association properties of long GAA.TTC repeats in R.R.Y triplex structures from Friedreich ataxia. Mol Cell1999;3(4):465-75.Lodi R, Cooper JM, Bradley JL, Manners D, Styles P, Taylor DJ, et al. Deficit of in vivo mitochondrial ATP production in patients with Friedreich ataxia. Proc Natl Acad Sci U S A 1999;96(20):11492-5.Babcock M, de Silva D, Oaks R, Davis-Kaplan S, Jiralerspong S, Montermini L, et al. Regulation of mitochondrial iron accumulation by Yfh1p, a putative homolog of frataxin. Science 1997;276(5319):1709-12.Wilson RB, Roof DM. Respiratory deficiency due to loss of mitochondrial DNA in yeast lacking the frataxin homologue. Nat Genet 1997;16(4):352-7.Ramazzotti A, Vanmansart V, Foury F. Mitochondrial functional interactions between frataxin and Isu1p, the iron-sulfur cluster scaffold protein, in Saccharomycescerevisiae. FEBS Lett 2004;557(1-3):215-20.Foury F, Cazzalini O. Deletion of the yeast homologue of the human gene associated with Friedreich ataxiaelicits iron accumulation in mitochondria. FEBS Lett1997;411(2-3):373-7.Foury F, Talibi D. Mitochondrial control of iron homeostasis. A genome wide analysis of gene expression in a yeast frataxin-deficient strain. J Biol Chem 2001;276(11):7762-8.Koeppen AH. Friedreich ataxia: pathology, pathogenesis, and molecular genetics. J Neurol Sci 2011;303(1-2):1-12.Kish SJ, Bergeron C, Rajput A, Dozic S, Mastrogiacomo F, Chang LJ, et al. Brain cytochrome oxidase in Alzheimer’s disease. J Neurochem 1992;59(2):776-9.Schapira AH. Mitochondrial complex I deficiency in Parkinson’s disease. Adv Neurol 1993;60(1):288-91.Lu F, Selak M, O’Connor J, Croul S, Lorenzana C, Butunoi C, et al. Oxidative damage to mitochondrial DNA and activity of mitochondrial enzymes in chronicactive lesions of multiple sclerosis. J Neurol Sci2000;177(2):95-103.Bradley JL, Blake JC, Chamberlain S, Thomas PK, Cooper JM, Schapira AH. Clinical, biochemical and molecular genetic correlations in Friedreich ataxia. Hum Mol Genet 2000;9(2):275-82.Rotig A, de Lonlay P, Chretien D, Foury F, Koenig M, Sidi D, et al. Aconitase and mitochondrial iron-sulphur protein deficiency in Friedreich ataxia. Nat Genet1997;17(2):215-7.van den Ouweland JM, Bruining GJ, Lindhout D, Wit JM, Veldhuyzen BF, Maassen JA. Mutations in mitochondrial tRNA genes: non-link age with syndromes of Wolfram and chronic progressive external ophthalmoplegia. Nucleic Acids Res 1992;20(4):679-82.Harding AE. Friedreich ataxia: a clinical and genetic study of 90 families with an analysis of early diagnostic criteria and intrafamilial clustering of clinical features. Brain 1981;104(3):589-620.Geoffroy G, Barbeau A, Breton G, Lemieux B, Aube M, Leger C, et al. Clinical description and roentgenologic evaluation of patients with Friedreich ataxia. Can J Neurol Sci 1976;3(4):279-86.Campuzano V, Monter mini L, Molto MD, Pianese L, Cossee M, Cavalcanti F, et al. Friedreich ataxia: autosomal recessive disease caused by an intronic GAA triplet repeat expansion. Science 1996;271(5254):1423-7.Tan DJ, Bai RK, Wong LJ. Comprehensive scanning of somatic mitochondrial DNA mutations in breast cancer. Cancer Res 2002;62(4):972-6.Sanchez M, Anitua E, Azofra J, Andia I, Padilla S, Mujika I. Comparison of surgically repaired Achilles tendon tearsusing platelet-rich fibrin matrices. Am J Sports Med2007;35(2):245-51.Anderson S, Bankier AT, Barrell BG, de Bruijn MH, Coulson AR, Drouin J, et al. Sequence and organization of the human mitochondrial genome. Nature1981;290(5806):457-65.22. Marmolino D. Friedreich ataxia: past, present and future.Brain Res Rev 2011;67(1-2):311-30.Houshmand M, Mahmoudi T, Panahi MS, Seyedena Y,Saber S, Ataei M. Identification of a new human mt DNA polymorphism (A14290G) in the NADH dehydrogenase subunit 6 gene. Braz J Med Biol Res 2006;39(6):725-30.Rona RJ, Reynolds A, Allsop M, Morris RW, Morgan M, Mandalia S. Audit from preschool developmental surveillance of vision, hearing, and language referrals. Arch Dis Child 1991;66(8):921-6.Heidari MM, Houshmand M, Hosseinkhani S, Nafissi S, Scheiber-Mojdehkar B, Khatami M. A novel mitochondrial heteroplasmic C13806A point mutation associated with Iranian Friedreich ataxia. Cell Mol Neurobiol 2009;29(2):225-33.Covarrubias D, Bai RK, Wong LJ, Leal SM. Mitochondrial DNA variant interactions modify breast cancer risk. J Hum Genet 2008;53(10):924-8.Pulkes T, Sweeney MG, Hanna MG. Increased risk of stroke in patients with the A12308G polymorphism in mitochondria. Lancet 2000;356(9247):2068-9.Wei YH. Oxidative stress and mitochondrial DNA mutations in human aging. Proc Soc Exp Biol Med1998;217(1):53-63.Hess JF, Parisi MA, Bennett JL, Clayton DA. Impairment of mitochondrial transcription termination by a point mutation associated with the MELAS subgroup of mitochondrial encephalomyopathies. Nature 1991;351(6323):236-9.

Novel and heteroplasmic mutations in mitochondrial tRNA genes in Brugada syndrome

  Background: Brugada syndrome (BrS) is a rare cardiac arrhythmia characterized by sudden death associated with electrocardiogram patterns characterized by incomplete right bundle-branch block and ST-segment elevations in the anterior precordial leads. This syndrome predominantly is seen in younger males with structurally normal hearts. Mitochondrial variants particularly mt-tRNA mutations, are hot spots that lead to cardiological disorders. Previous studies have shown that mutations in mitochondrial tRNA genes play an important causal or modifying role in BrS. The present study aims to evaluate the involvement of mitochondrial tRNA genes in arrhythmogenic BrS. Methods: In this study, 40 Iranian patients were investigated for the presence of the mutations in 6 mitochondrial tRNA genes (tRNA Ile, Met, Gln, Asn, Ala and Trp) by PCR-SSCP analysis. Results: There were 4 mutations in tRNA genes, that for first time, were found in BrS patients and these mutations were not in controls. Three of them were heteroplasmic and located in tRNAGln (T4377A) and tRNAMet (G4407A and C4456T) which were assessed as pathogenic mutations. A homo­plasmic variant (5580T > C) in tRNATrp gene was located within the junction region between tRNATrp and tRNAAla genes. This mutation may disturb the processing of mt-tRNATrp. Conclusions: The results of this study suggest that mutations in mitochondrial tRNA genes might lead to deficiencies in translational process of critical proteins of the respiratory chain and potentially lead to BrS in Iranian subjects. (Cardiol J 2018; 25, 1: 113–119

The association between TNP2 gene polymorphisms and Iranian infertile men with varicocele: A case-control study

Background: Numerous researches have provided great evidence that revealed the relationship between varicocele and sperm DNA damage. Objective: Because of the crucial role of nuclear transition proteins (TPs) in sperm DNA condensation and integrity, this case-control study was designed to study TNP2 gene nucleotide variations in Iranian patients with varicocele. Materials and Methods: PCR-SSCP and DNA sequencing were used to search for mutations in exons 1 & 2 of the TNP2 gene in 156 infertile patients with varicocele and 150 fertile men. Results: The results of sequencing showed three variants at positions c.301C > T (p.R101C), c.391C > T (p.R131 W), and g.IVS1-26G >C (rs8043625) of TNP2 gene. It was found that varicocele risk in men who have the CC genotype of g.IVS1-26G >C SNP is higher than those who don’t have these genotypes (according to Co-dominant model, Dominant model, Recessive model, and Over-dominant model). The haplotype-based analysis showed that (C/C/T) and (C/T/T) haplotypes were a risk factor of in patients with varicocele compared to controls (OR = 3.278, p = 0.000 and OR= 9.304, p = 0.038, respectively). Conclusion: Because of the significant difference in the genotype and allele frequencies of g.IVS1-26G >C SNP in the intronic region of TNP2 in patients with varicocele compared with controls and also because of the high conservation of this SNP position during evolution, this SNP may be involved in some important processes associated with the expression of this gene like mRNA splicing, but the exact mechanism is not clear

Mitochondrial mutations in protein coding genes of respiratory chain including complexes IV, V, and MT-TRNA genes are associated risk factors for congenital heart disease

Most studies aiming at unraveling the molecular events associated with cardiac congenital heart disease (CHD) have focused on the effect of mutations occurring in the nuclear genome. In recent years, a significant role has been attributed to mitochondria for correct heart development and maturation of cardiomyocytes. Moreover, numerous heart defects have been associated with nucleotide variations occurring in the mitochondrial genome, affecting mitochondrial functions and cardiac energy metabolism, including genes encoding for subunits of res-piratory chain complexes. Therefore, mutations in the mitochondrial genome may be a major cause of heart dis-ease, including CHD, and their identification and characterization can shed light on pathological mechanisms occurring during heart development. Here, we have analyzed mitochondrial genetic variants in previously re-ported mutational genome hotspots and the flanking regions of mt-ND1, mt-ND2, mt-COXI, mt-COXII, mt-ATPase8, mt-ATPase6, mt-COXIII, and mt-tRNAs (Ile, Gln, Met, Trp, Ala, Asn, Cys, Tyr, Ser, Asp, and Lys) en-coding genes by polymerase chain reaction-single stranded conformation polymorphism (PCR-SSCP) in 200 pa-tients with CHD, undergoing cardiac surgery. A total of 23 mitochondrial variations (5 missense mutations, 8 synonymous variations, and 10 nucleotide changes in tRNA encoding genes) were identified and included 16 novel variants. Additionally, we showed that intracellular ATP was significantly reduced (P=0.002) in CHD pa-tients compared with healthy controls, suggesting that the mutations have an impact on mitochondrial energy production. Functional and structural alterations caused by the mitochondrial nucleotide variations in the gene products were studied in-silico and predicted to convey a predisposing risk factor for CHD. Further studies are necessary to better understand the mechanisms by which the alterations identified in the present study contribute to the development of CHD in patients.info:eu-repo/semantics/publishedVersio

Molecular Analysis of rs2070744 and rs1799983 Polymorphisms of NOS3 Gene in Iranian Patients With Multiple Sclerosis

Introduction: Multiple Sclerosis (MS) is a disease of central nervous system that mainly causes lesions or plaques in the spinal cord and brain. The purpose of this study was to analyze the relation between c.-813C>T (rs2070744) and c.894G>T (rs1799983) polymorphisms of NOS3 gene and MS in Iranian patients. Methods: A total of 78 patients with MS and 80 healthy controls were screened for NOS3 (rs2070744 and rs1799983) Single Nucleotide Polymorphisms (SNPs) by tetra-primer multiplex ARMS-PCR and PCR-RFLP. Results: Genotype frequencies of the c.-813C>T polymorphism in patients compared to controls were as follows: 53.8% to 80.0% for TT genotype, 41.0% to 18.8% for TC genotype, and 5.1% versus 1.2% for CC genotype (P=0.001). The frequencies of GG genotype was 57.7% and 78.8% and for GT genotype of c.894G>T polymorphism in patients compared to control subjects was 42.3% and 21.2%, respectively (P=0.004). Conclusion: Our results indicate that the studied NOS3 polymorphisms may be associated with MS in Iranian patients

The Study of Nitric Oxide Synthase 3 (NOS3) T-786C and 4a4b Gene Polymorphism in Iranian Men with Varicocele

Background and Objectives: Varicocele is one of the most common causes of male infertility. Varicocele is an abnormal dilatation and tortuosity of veins of the pampiniform plexus, which drain the testis. Studies have shown that elevated level of oxidative stress markers, such as nitric oxide (NO) in the dilated veins of patients with varicocele impair testicular function. The aim of this study, was to investigate the relationship between nitric oxide synthase 3 (NOS3), T-786C, and 4a4b gene polymorphism as a common genetic factor with the risk of varicocele in Iranian men.   Methods: The association of NOS3 T-786C and 4a4b gene polymorphisms in 60 Iranian men with varicocele and 61 control samples, were investigated using Multiplex-ARMS PCR and conventional PCR techniques. Data were statistically analyzed by t-test at the significance level of p<0.05.   Results: The results revealed that among 60men with varicocele, 95% had -786 TTgenotype, 3.3% had heterozygotic genotype T-786C, and 1.6%, were CC in T-786C polymorphism. In addition, just 5% were heterozygote (ab) in 4a4b polymorphism and 95% had wild type genotype (aa), which was not statistically significant.   Conclusion: In this study, the majority of individuals had wild-type genotypes TT and aa in T-786C and 4a4b polymorphisms, respectively. According to this data, no significant differences were found between NOS3 gene T-786C and 4a4b polymorphisms in the individuals with varicocele. It is worth noting that further studies should be performed to confirm these finding

Relationship of the MTHFD1 (rs2236225), eNOS (rs1799983), CBS (rs2850144) and ACE (rs4343) gene polymorphisms in a population of Iranian pediatric patients with congenital heart defects

Congenital heart defects are structural cardiovascular malformations that arise from abnormal formation of the heart or major blood vessels during the fetal period. To investigate the association of 4 single nucleotide polymorphisms (SNPs) in the MTHFD1, eNOS, CBS and ACE genes, we evaluated their relationship with CHD in Iranian patients. In this case–control study, a total of 102 children with CHD and 98 control children were enrolled. Four SNPs including MTHFD1 G1958A, eNOS G894T, CBS C-4673G and ACE A2350G were genotyped by PCR-SSCP, Multiplex ARMS PCR and PCR-RFLP methods and confirmed by direct sequencing. We genotyped 102 patients and 98 controls for four polymorphisms by statistically analysis. There were three SNPs including MTHFD1 G1958A, eNOS G894T and ACE A2350G which might increase the risk of CHD, but CBS C-4673G was not significantly different between patients and controls. (P = 0.017, P = 0.048, P = 0.025 and P = 0.081 respectively). The allele frequencies of three SNPs for MTHFD1 G1958A, eNOS G894T and ACE A2350G in CHD are higher than that in control. Our results show that there is a significant relationship between MTHFD1 G1958A, eNOS G894T and ACE A2350G polymorphisms with CHD. Therefore, The AA and GA genotypes of MTHFD1 G1958A, TT and GT genotypes of eNOS G894T and the AA and GA genotypes of ACE A2350G are susceptible factors for CHD and may increase the risk of CHD