title: Original tandem duplication in FXIIIA gene with splicing site modification and four amino acids insertion causes factor XIII deficiency.
abstract: : Recessive mutations of F13A gene are reported to be responsible of FXIIIA subunit deficiency (FXIIIA). In all, some intronic nucleotide changes identified in this gene were investigated by in-silico analysis and occasionally supported by experimental data or reported in some cases as a polymorphism. To determine the molecular defects responsible of congenital factor XIII deficiency in Libyan patient, molecular analysis was performed by direct DNA sequencing of the coding regions and splice junctions of the FXIIIA subunit gene (F13A). A splicing minigene assay was used to study the effect of this mutation. Bioinformatics exploration was fulfilled to conceive consequences on protein. A 12-bp duplication straddling the border of intron 9 and exon 10 leads to two 3' acceptor splice sites, resulting in silencing of the downstream wild 3' splice site. It caused an in-frame insertion of 12 nucleotides into mRNA and four amino acids into protein. Bioinformatic analysis predicts that the insertion of four amino acids affects the site 3 of calcium binding site, which disturbs the smooth function of the FXIIIA peptide causing the factor XIII deficiency. This study showed that a small duplication seems to weaken the original 3' splice site and enhance the activation of a new splice site responsible for an alternative splicing. It would be interesting to examine the underlying molecular mechanism involved in this rearrangement.
authors.affiliation: aLaboratoire de Génétique Moléculaire Humaine, Faculté de Médecine de Sfax, Université de Sfax, Sfax, Tunisia bCentre de Recherche, Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Quebec City, Québec, Canada cService d'Hématologie. C.H.U., Hédi Chaker de Sfax dLaboratoire de Biochimie et de Génie Enzymatique des Lipases, ENIS, Université de Sfax, Sfax, Tunisia.
authors.forename: Nacim
authors.initials: N
authors.lastname: Louhichi
authors.forename: Ikhlass
authors.initials: I
authors.lastname: Haj Salem
authors.forename: Moez
authors.initials: M
authors.lastname: Medhaffar
authors.forename: Nabil
authors.initials: N
authors.lastname: Miled
authors.forename: Ahmad F
authors.initials: AF
authors.lastname: Hadji
authors.forename: Leila
authors.initials: L
authors.lastname: Keskes
authors.forename: Faiza
authors.initials: F
authors.lastname: Fakhfakh
mesh_terms: D000596:Amino Acids; D005177:Factor XIII Deficiency / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D012326:RNA Splicing / Q000235:genetics*; D020080:Tandem Repeat Sequences / Q000235:genetics*; D014162:Transfection
chemical_list: D000596:Amino Acids