Abstract 19944: A PDE5A Gene Mutation Affecting Risk of Myocardial Infarction

• Published in: Circulation (New York, N.Y.) N.Y.), 2014-11, Vol.130 (suppl_2)
• Main Authors: Dang, Tan An, Braenne, Ingrid, Aherrahrou, Redouane, Tennstedt, Stephanie, Kessler, Thorsten, Hengstenberg, Christian, Erdmann, Jeanette, Schunkert, Heribert
• Format: Article
• Language: English
• ISSN: 0009-7322; 1524-4539
• DOI: 10.1161/circ.130.suppl_2.19944

Abstract only INTRODUCTION: Multiple frequent genetic variants were shown to affect myocardial infarction (MI) risk. Genetic causes for familial clustering of MI are less clear. We aimed to identify and characterize the molecular underpinnings of premature MI in a family with 9 affected individuals. METHODS AND RESULTS: Employing cosegregation analysis and exome sequencing we identified a mutation in the phosphodiesterase 5A ( PDE5A ) gene in all affected individuals (LOD score 3.16). It is located in an alternative promoter site of PDE5A and leads to a premature stop codon in one of the PDE5A isoforms (p.Lys7Ter). PDE5A encodes for three isoforms catalyzing cGMP, a second messenger mediating vasodilation and platelet passivation. Effects of the stop codon were investigated by western blot analysis after in vitro mutagenesis. Overexpression in HEK cells did not reveal a loss of transcript but the expression of a N-terminally truncated protein. Deeper analyses of translation initiation by deletion of possible transcription starts via in vitro mutagenesis uncovered a protein lacking 91 amino acids compared to the full-length isoform. Activity of the truncated PDE5A was measured using PDEGlo (Promega). Moreover, the effect of the variant on the alternative promoter site was analyzed by luciferase assays. Therefore, a 600 bp fragment containing either the mutated or WT allele was cloned into a pGL4.10 vector (Promega). Overexpression in HEK cells showed 40% increase of promoter activity with the mutated allele (p