The School of Arts & Sciences

Department of Natural Sciences

Osman El Maarri

Dr. El-Maarri joined LAU in spring 2016 after establishing a carrier in biomedical research at the University of Bonn, Germany. He studied biology at AUB and went further to study Biomedical Engineering at Bogazici University (Istanbul) where he pursued a Ph.D. in molecular genetics. Since 1998, he worked at Max Plank Institute for Molecular Genetics (Berlin) and at the Institute of Experimental Hematology and Transfusion Medicine at the medical faculty of the University of Bonn. He established several research directions related to biological research and medical genetics. His main research interest is medical genetics that include intracellular trafficking, cellular modeling of genetic diseases (using stem cells), and genetics/epigenetic deregulations associated with human diseases. 


Original Research Articles

  1. Jarjanazi, H., Timur, A., El-Maarri, O., and Caglayan, S. H., “Analysis of two microsatellite repeat polymorphisms of factor VIII gene in the Turkish population,” British Journal of Hematology, pp 589-593, March 1998.
  2. El-Maarri, Osman, Olek, A., Balaban, B., Montag, M., Van Der Ven H, Urman, B., Olek, K., Caglayan, S. H., Walter, J. and Oldenburg, J., “Methylation Levels at Selected CpG Sites in the Factor VIII and FGFR3 Genes in Mature Male and Female Germ Cells: Implications For Male Driven Evolution”, American Journal of Human Genetics, 63, 1001-1008, October, 1998.
  3. El-Maarri, Osman, Oldenburg, J. and Caglayan, S, “Intron 22-specific long PCR for the Xba I polymorphism in the factor VIII gene”, British Journal of Hematology, 105: issue 4: 1120-1122, June, 1999.
  4. El-Maarri, Osman, Kavakli, K., and Caglayan, S. H., “Intron 22 Inversion in the Turkish Hemophilia A Patients: Prevalence and Haplotype Analysis“, Hemophilia, July, 169-173, 1999.
  5. Oldenburg, Johannes, Rost, S, El-Maarri, Osman, Leuer, M, Olek K., Muler C.R. and Schwaab R, “ De novo factor VIII intron 22 inversion in a female carrier presents as a somatic mosaicism”, Blood, 15 October, Vol. 96, No 8, 2905-2906, 2000.
  6. Martina Paulsen, El-Maarri Osman, Engermann S, Franck O, Shrodicke M, Davis KR, Bowden LM, Reik W, and Jeorn Walter, “Characterization and sequence analysis of the  mouse distal chromosome 7 imprinting cluster”, Human Molecular Genetics, Vol 9, No 12, July 22, 1829-1841, 2000.
  7. Prissette Marine, El-Maarri Osman, Arnaud Danielle, Walter Joern and Philipe Avner, Methylation profiles of  DXPas34 locus during the onset of X-inactivation, Human Molecular Genetics, Vol 10, No 1, Jan, pp 31-38, 2001.
  8. Osman El-Maarri, Karin Buiting, Edwin G. Peery, Peter M. Kroisel, Basak Balaban, Klaus Wagner, Bulent Urman, Julia Heyd, Christina Lich, Camilynn I. Brannan, Jِrn Walter and Bernhard Horsthemke, Maternal methylation imprints in 15q11-q13 are established after fertilization, Nature Genetics,Vol 27, pp 341-344, March 2001.
  9. Irina Stancheva, Osman El-Maarri, Joern Walter, Alain Niveleau and Richard R. Meehan, DNA Methylation at promoter regions regulates the timing of gene activation in Xenopus laevis embryos, Developmental Biology,  2002 Mar 1; Vol 243, pp155-65.
  10. Osman El-Maarri, Ursula Herbiniaux, Joern Walter and Johannes Oldenburg, A rapid, quantitative, non-radioactive bisulfite-SNuPE-IP RP HPLC assay for methylation analysis at specific CpG sites, Nucleic Acid Research, 2002, Vol 30, no 6 e25.
  11. Petra Hajkova, Silvia Erhardt, Natasha Lane, Thomas half, Osman El-Maarri, Wolf Reik, Jeorn Walter, Azim Surani, Epigenetic reprogramming in mouse primordial germ cells, Mechanisms of Development, 2002 Sep, Vol 117, p15.
  12. Karin Buiting, Stephanie Groß, Christina Lich, Gabriele Gillessen-Kaesbach, Osman El-Maarri, and Bernhard Horsthemke, Epimutations in Prader-Willi and Angelman syndrome: a molecular study of 136 patients with an imprinting defect, American Journal of Human Genetics, 2003 Mar;72(3):571-7.
  13. Osman El-Maarri, Muhieddine Seoud, Philippe Coullin, Ursula Herbiniaux, Johannes Oldenberg, Guy Rouleau, Rima Slim, Maternal alleles acquiring paternal methylation patterns in biparental complete hydatidiform moles, Human Molecular Genetics, 2003 Jun 15;12(12):1405-13.
  14. Osman El-Maarri, Herbiniaux U, Graw J, Schroder J, Terzic A, Watzka M, Brackmann HH, Schramm W, Hanfland P, Schwaab R, Muller CR, Oldenburg J. Detailed RNA analysis in haemophilia A patients with previously undetectable mutations, Journal of thrombosis and Heamostasis, 2005 Feb;3(2):332-9.
  15. Osman El-Maarri, Seoud M, Riviere JB, Oldenburg J, Walter J, Rouleau G, Slim R. Patients with familial biparental hydatidiform moles have normal methylation at imprinted genes. Eur J Hum Genet. 2005 Apr;13(4):486-90.
  16. Osman El-Maarri, Singer H, Klein C, Watzka M, Herbiniaux U, Brackmann H, Schröder J, Graw J, Müller CR, Schramm W, Schwaab R, Haaf T, Hanfland P, Oldenburg J, Lack of F8 mRNA: a novel mechanism leading to Hemophilia A, Blood, 2006 Apr 1;107(7):2759-65.
  17. Loreth RM, Osman El-Maarri, Schroder J, Budde U, Herrmann FH, Oldenburg J. Haemophilia A in a female caused by coincidence of a Swyer syndrome and a missense mutation in factor VIII gene. Thromb Haemost. 2006 Apr;95(4):747-8.
  18. Schroder J, Osman El-Maarri, Schwaab R, Muller CR, Oldenburg J. Factor VIII intron-1 inversion: frequency and inhibitor prevalence. J Thromb Haemost. 2006 May;4(5):1141-3.
  19. Berber E, Fidanci ID, Un C, Osman El-Maarri, Aktuglu G, Gurgey A, Celkan T, Meral A, Oldenburg J, Graw J, Akar N, Caglayan H. Sequencing of the factor 8(F8) coding regions in 10 Turkish hemophilia A patients reveals three novel pathological mutations, and one rediagnosis of von Willebrand’s disease type 2N. Haemophilia. 2006 Jul;12(4):398-400.
  20. Djuric U, Osman El-Maarri, Lamb B, Kuick R, Seoud M, Coullin P, Oldenburg J, Hanash S, Slim R. Familial molar tissues due to mutations in the inflammatory gene, NALP7, have normal postzygotic DNA methylation. Hum Genet. 2006 Oct;120(3):390-5.
  21. Pavlova A, Osman El-Maarri, Luxembourg B, Lindhoff-Last E, Kochhan L, Bruhn H, Delev D, Watzka M, Seifrid E, Oldenburg J. Multiplex PCR followed by DHPLC based detection of heterozygous large deletions in the antithrombin gene. Haematologica. 2006 Sep;91(9):1264-7
  22. Mikeska T, Bock C, Osman El-Maarri, Hubner A, Ehrentraut D, Schramm J, Felsberg J, Kahl P, Buttner R, Pietsch T, Waha A. Optimization of quantitative MGMT promoter methylation analysis using pyrosequencing and combined bisulfite restriction analysis. J Mol Diagn. 2007 Jul;9(3):368-81.
  23. El-Maarri Osman, Becker T, Junen J, Manzoor SS, Diaz-Lacava A, Schwaab R, Wienker T, Oldenburg J. Gender specific differences in levels of DNA methylation at selected loci from human total blood: a tendency toward higher methylation levels in males. Hum Genet. 2007 Dec;122(5):505-14.
  24. Müller J, El-Maarri Osman, Oldenburg J, Pötzsch B, Mayer G. Monitoring the progression of the in vitro selection of nucleic acid aptamers by denaturing high-performance liquid chromatography. Anal Bioanal Chem. 2008 Feb;390(4):1033-7.
  25. Pavlova A, Förster T, Delev D, Schröder J, El-Maarri O, Müller-Reible C, Oldenburg J. Heterozygous large deletions of Factor 8 gene in females identified by multiplex PCR-LC. Haemophilia. 2008 May;14(3):599-606.
  26. El-Maarri O, Kareta MS, Mikeska T, Becker T, Diaz-Lacava A, Junen J, Nüsgen N, Behne F, Wienker T, Waha A, Oldenburg J, Chédin F. A systematic search for DNA methyltransferase polymorphisms reveals a rare DNMT3L variant associated with subtelomeric hypomethylation. Hum Mol Genet. 2009 May 15;18(10):1755-68. Epub 2009 Feb 26.
  27. El-Maarri O, Walier M, Behne F, van Üüm J, Singer H, Diaz-Lacava A, Nuesgen N, Niemann B, Watzka M, Reinsberg, J, van der Ven H, Wienker T, Stoffel-Wagner B, Schaab R, Oldenburg J. Methylation at Global LINE-1 Repeats in Human Blood Are Affected by Gender but Not by Age or Natural Hormone Cycles. Plos One. 2011: 6: e16252.
  28. Setty P, Gessi M, Waha A, Hammes J, El-Maarri O, Pietsch T and Waha A. Sensitive Determination of BRAF Copy Number in Clinical Samples by Pyrosequencing. Diagn Mol Pathol. 2011 Sep;20(3):148-57
  29. Schreiner F, El-Maarri O, Gohlke B, Stutte S, Nuesgen N, Mattheisen M, Fimmers R, Bartmann P, Oldenburg J, Woelfle J. Association of COMT genotypes with S-COMT promoter methylation in growth-discordant monozygotic twins and healthy adults. BMC Med Genet. 2011 Sep 1;12(1):115.
  30. Nieratschker V, Grosshans M, Frank J, Strohmaier J, von der Goltz C, El-Maarri O, Witt SH, Cichon S, Nöthen MM, Kiefer F, Rietschel M. Epigenetic alteration of the dopamine transporter gene in alcohol-dependent patients is associated with age. Addict Biol. 2012 Apr 16. doi: 10.1111/j.1369-1600.2012.00459.x. [Epub ahead of print]
  31. Dauksa A, Gulbinas A, Barauskas G, Pundzius J, Oldenburg J, El-Maarri O. Whole blood DNA aberrant methylation in pancreatic adenocarcinoma shows association with the course of the disease: a pilot study. PLoS One. 2012;7(5):e37509.
  32. Singer H, Walier M, Nuesgen N, Meesters C, Schreiner F, Woelfle J, Wineker T, Kalsscheuer V, Becker T, Schwaab R, Oldenburg J and El-Maarri O. Methylation of Specific LINE-1 Promoter Regions are Lower on the Inactive X Chromosome, Have a Tendency of Being Higher on Autosomes in Smaller Genomes and Show Considerable Variability in Healthy Individuals. Hum Mol Genetics. 2012 Jan 1;21(1):219-35.
  33. Pezeshkpoor B, Rost S, Oldenburg J, El-Maarri O. Identification of a third rearrangement at Xq28 that causes severe hemophilia A as a result of homologous recombination between inverted repeats. J Thromb Haemost. 2012 Aug;10(8):1600-8.
  34. Daugela L, Walier M, Nüsgen N, Schwaab R, Oldenburg J, and El-Maarri O. Measurements of DNA methylation at seven loci in various tissues of CD1 mice. PLoS One. 2012;7(9):e44585.
  35. Pezeshkpoor B, Zimmer N, Marquardt N, Nanda I, Haaf T, Budde U, Oldenburg J, and El-Maarri O. Deep intronic ‘mutations’ cause mild hemophilia A: Application of Next Generation Sequencing in patients without detectable mutation in F8 cDNA. J Thromb Haemost. 2013 Sep;11(9):1679-87.
  36. Schreiner F, Gohlke B, Stutte S, Bartmann P, Hecher K, Oldenburg J, El-Maarri O, Woelfle J. 11p15 DNA-methylation analysis in monozygotic twins with discordant intrauterine development due to severe twin-to-twin transfusion syndrome. Clin Epigenetics. 2014 Mar 28;6(1):6.
  37. Heike Singer, Arijit Biswas, Nicole Zimmer, Christiane Messaed, Johannes Oldenburg, Rima Slim and Osman El-Maarri, NLRP7 inter-domain interactions: The NACHT-associated domain (NAD) is the physical mediator for oligomeric assembly. Molecular Human Reproduction, 2014 Oct. 20 (10):990-1001.
  38. Albertas Dauksa, Antanas Gulbinas, Zilvinas Endzinas, Johannes Oldenburg and Osman El-Maarri. DNA methylation at selected CpG sites in peripheral blood leukocytes is predictive of gastric cancer. Anti Cancer Research. 2014 Oct;34(10):5381-8.
  39. B. Pezeshkpoor, B.D.M., Theophilus, A.M. Guilliatt, J. Oldenburg, M.D. Williams and O. El-Maarri. The novel identification and characterization of a breakpoint in F8 gene leading to severe haemophilia A: the importance of an individualized approach to gene analysis. Hemophilia. In press: 2015 Jan 27. doi: 10.1111/hae.12606. [Epub ahead of print]
  40. Nicole Nuesgen, Wolfgang Göring, Albertas Dauksa, Arijit Biswas, Amit Sharma, Ioanna Dimitriou, Mohammad Ahmer Jamil, Heike Singer, Rolf Fimmers, Holger Fröhlich, Johannes Oldenburg, Antanas Gulbinas, Wolfgang Schulz and Osman El-Maarri. Analysis of global and locus-specific LINE-1 methylation in tumors reveals the presence of ‘seed’ CpGs prone to hypomethylation. Clinical Epigenetics, In press.
  41. Heike Singer, Arijit Biswas, Nicole Zimmer, Johannes Oldenburg and Osman El-Maarri. NLRP7, the defected protein in hydatidiform molar pregnancy (HYDM1), interact with the transcriptional repressor ZBTB16, PLOS One, Under review.
  42. Amit Sharma, Nicole Nuesgen, Mohammad Ahmer Jamil, Felix Schreiner, Lutz Priebe, Per Hoffmann, Stefan Herns, Markus Nöthen, Holger Fröhlich, Johannes Oldenburg, Joachim Woelfle, and Osman El-Maarri. DNA methylation signature in total blood reveals distinct characteristics of human X-chromosome numerical abnormality, submitted to Clinical Epigenetics. 2015 Jul 28;7:76. doi: 10.1186/s13148-015-0112-2. eCollection 2015.
  43. Hilger AC, Halbritter J, Pennimpede T, van der Ven A, Sarma G, Braun DA, Porath JD, Kohl S, Hwang DY, Dworschak GC, Hermann BG, Pavlova A, El-Maarri O, Nöthen MM, Ludwig M, Reutter H, Hildebrandt F. Targeted Resequencing of 29 Candidate Genes and Mouse Expression Studies Implicate ZIC3 and FOXF1 in Human VATER/VACTERL Association. Hum Mutat. 2015 Dec;36(12):1150-4. doi: 10.1002/humu.22859. Epub 2015 Sep 14.
  44. Pezeshkpoor B, Berkemeier AC, Czogalla KJ, Oldenburg J, El-Maarri O. Evidence of pathogenicity of a mutation in 3’ untranslated region causing mild haemophilia A. Haemophilia. 2016 Jul;22(4):598-603. doi: 10.1111/hae.12923. Epub 2016 May 24.
  45. Skewed X-chromosome inactivation and XIST locus methylation levels do not contribute to the lower prevalence of Parkinson’s disease in females. Sharma A, Kaut O, Pavlova A, Fröhlich H, Ahmad A, Schmitt I, El-Maarri O, Oldenburg J, Wüllner U. Neurobiol Aging. 2017 Sep;57:248.e1-248.e5.

Review articles:

1.       Johannes Oldenburg, Osman El-Maarri, Rainer Schwaab, Inhibitor development in correlation to factor VIII genotypes. Haemophilia. 2002 Mar; 8 Suppl 2:23-9.

2.       Oldenburg J, Osman El-Maarri. New insight into the molecular basis of hemophilia A. Int J Hematol. 2006 Feb;83(2):96-102.

3.       Osman El-Maarri and Rima Slim, Familial Hydatidiform molar pregnancy: the germ line imprinting defect hypothesis?, in DNA Methylation: Basic mechanisms, Currents Topics in Microbiology and Immunology, Vol. 301, 2006, 2006;301:229-41.

4.       Pezeshkpoor B, Pavlova A, Oldenburg J, El-Maarri O. F8 genetic analysis strategies when standard approaches fail. Hamostaseologie. 2014 May 12;34(2):167-73.

5.       de Brasi C, El-Maarri O, Perry DJ, Oldenburg J, Pezeshkpoor B, Goodeve A. Genetic testing in bleeding disorders. Haemophilia. 2014 May;20 Suppl 4:54-8.

Books chapters:

1.      Petra Hajkova, Osman El-Maarri, Sabine Engelmann, Joachim Oswald, Alexandre Olek, and Joern Walter: DNA-methylation analysis by the bisulfite-assisted genomic sequencing method. A chapter in the series of Methods in Molecular Biology: Elsievier publisher, Methylation analysis. Methods Mol Biol. 2002; 200: 143-54.

2.      Osman El-Maarri, Johannes Oldenburg and Joern Walter; SIRPH: a rapid quantitative SNuPE-IP RP HPLC method for simultaneous methylation analysis at multiple CpG sites. A chapter in a book about dHPLC applications: “Genetic Variance Detection, Nuts and Bolts of DHPLC in Genomics”; DNA press 2003 (LLC), editor: Karl Hecker. Pp 151-162.

3.      Osman El-Maarri, Manfred Kueper, Johannes Oldenburg, Jeorn Walter; Quantitative DNA-Methylation Analysis by the Bisulfite Conversion Method.  A chapter in ‘PCR Technology: Current Innovations’ second edition; CRC press 2004, editors: Thomas Weissensteiner, Hugh G. Griffin and Annette Griffin. Pp 175-185.

4.      Osman El-Maarri, DNA methylation and human diseases. A chapter in the book “Peroxisomal disorders and regulation of genes” (Kluwer/Plenum, 2003) editors: Frank Roels, Myriam Baes and Sylvia De Bie. Pp 135-144.

5.      Osman El-Maarri, Methods: DNA methylation. A chapter in the book “Peroxisomal disorders and regulation of genes” (Kluwer/Plenum, 2003) editors: Frank Roels, Myriam Baes and Sylvia De Bie. Pp 197-204.

6.      Osman El-Maarri. SIRPH analysis: SNuPE with IP-RP-HPLC for quantitative measurements of DNA methylation at specific CpG sites. Methods Mol Biol. 2004; 287:195-205.

7.      Heike Singer, Nicole Nuesgen and Osman El-Maarri, SIRPH: an HPLC based SNuPE for quantitative methylation measurement at specific CpG sites. Methods Mol Biol. 2011;791:89-100. doi: 10.1007/978-1-61779-316-5_7.

Academic Degrees

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