title: ALDH1A2 (RALDH2) genetic variation in human congenital heart disease.
abstract: BACKGROUND
  Signaling by the vitamin A-derived morphogen retinoic acid (RA) is required at multiple steps of cardiac development. Since conversion of retinaldehyde to RA by retinaldehyde dehydrogenase type II (ALDH1A2, a.k.a RALDH2) is critical for cardiac development, we screened patients with congenital heart disease (CHDs) for genetic variation at the ALDH1A2 locus.
  
  
  METHODS
  One-hundred and thirty-three CHD patients were screened for genetic variation at the ALDH1A2 locus through bi-directional sequencing. In addition, six SNPs (rs2704188, rs1441815, rs3784259, rs1530293, rs1899430) at the same locus were studied using a TDT-based association approach in 101 CHD trios. Observed mutations were modeled through molecular mechanics (MM) simulations using the AMBER 9 package, Sander and Pmemd programs. Sequence conservation of observed mutations was evaluated through phylogenetic tree construction from ungapped alignments containing ALDH8 s, ALDH1Ls, ALDH1 s and ALDH2 s. Trees were generated by the Neighbor Joining method. Variations potentially affecting splicing mechanisms were cloned and functional assays were designed to test splicing alterations using the pSPL3 splicing assay.
  
  
  RESULTS
  We describe in Tetralogy of Fallot (TOF) the mutations Ala151Ser and Ile157Thr that change non-polar to polar residues at exon 4. Exon 4 encodes part of the highly-conserved tetramerization domain, a structural motif required for ALDH oligomerization. Molecular mechanics simulation studies of the two mutations indicate that they hinder tetramerization. We determined that the SNP rs16939660, previously associated with spina bifida and observed in patients with TOF, does not affect splicing. Moreover, association studies performed with classical models and with the transmission disequilibrium test (TDT) design using single marker genotype, or haplotype information do not show differences between cases and controls.
  
  
  CONCLUSIONS
  In summary, our screen indicates that ALDH1A2 genetic variation is present in TOF patients, suggesting a possible causal role for this gene in rare cases of human CHD, but does not support the hypothesis that variation at the ALDH1A2 locus is a significant modifier of the risk for CHD in humans.
authors.affiliation: InCor - HC FMUSP, São Paulo, Brasil. mari.pavan@gmail.com
authors.forename: Marilene
authors.initials: M
authors.lastname: Pavan
authors.forename: Viviane F
authors.initials: VF
authors.lastname: Ruiz
authors.forename: Fábio A
authors.initials: FA
authors.lastname: Silva
authors.forename: Tiago J
authors.initials: TJ
authors.lastname: Sobreira
authors.forename: Roberta M
authors.initials: RM
authors.lastname: Cravo
authors.forename: Michelle
authors.initials: M
authors.lastname: Vasconcelos
authors.forename: Lívia P
authors.initials: LP
authors.lastname: Marques
authors.forename: Sonia M F
authors.initials: SM
authors.lastname: Mesquita
authors.forename: José E
authors.initials: JE
authors.lastname: Krieger
authors.forename: Antônio A B
authors.initials: AA
authors.lastname: Lopes
authors.forename: Paulo S
authors.initials: PS
authors.lastname: Oliveira
authors.forename: Alexandre C
authors.initials: AC
authors.lastname: Pereira
authors.forename: José
authors.initials: J
authors.lastname: Xavier-Neto
mesh_terms: D000080924:Aldehyde Dehydrogenase 1 Family; D002460:Cell Line; D002884:Chromosomes, Human, Pair 15; D005091:Exons; D020022:Genetic Predisposition to Disease; D014644:Genetic Variation; D055106:Genome-Wide Association Study; D006330:Heart Defects, Congenital / Q000235:genetics*; D006801:Humans; D015810:Linkage Disequilibrium; D009154:Mutation; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide; D017510:Protein Folding; D050697:Retinal Dehydrogenase / Q000235:genetics; D013771:Tetralogy of Fallot / Q000235:genetics
chemical_list: D000080924:Aldehyde Dehydrogenase 1 Family; C545372:ALDH1A2 protein, human; D050697:Retinal Dehydrogenase