title: Evidence for a functional genetic polymorphism of the human retinoic acid-metabolizing enzyme CYP26A1, an enzyme that may be involved in spina bifida.
abstract: BACKGROUND
  CYP26A1, together with CYP26B1 and CYP26C1, are key enzymes of all-trans retinoic acid (RA) inactivation and their specific and restricted expression in developing embryos participate in the fine tuning RA levels. As RA is a critical regulator of gene expression during embryonic development, the imbalance between the synthesis and degradation of RA during embryogenesis could contribute to malformations and developmental defects.
  
  
  METHODS
  A PCR-single strand conformation polymorphism (PCR-SSCP) strategy was developed to screen for CYP26A1 sequence variations that could affect the enzyme expression and/or activity and applied to DNA samples from 80 unrelated Caucasians, comprising 40 French healthy volunteers and 40 Italian patients with spina bifida. The consequence of the 1-bp deletion identified in the coding sequence was investigated by an in vitro functional assay using COS-7 cells.
  
  
  RESULTS
  A total of 7 polymorphisms were identified, comprising 1 nucleotide deletion in the coding sequence (g.3116delT) that results in a frameshift and consequently in the creation of a premature stop codon. The g.3116delT mutation is of particular interest because it was identified in a patient with spina bifida and likely encodes a truncated protein with no enzymatic activity, as demonstrated by our preliminary in vitro data.
  
  
  CONCLUSIONS
  Despite the fact that our findings could not show any evidence that the CYP26A1 genetic polymorphism has implications in the pathogenesis of spina bifida, this work represents the first description of a functional genetic polymorphism affecting the coding sequence of the human CYP26A1 gene.
authors.affiliation: Equipe d'accueil EA2679, Faculté de Médecine, Lille Cedex, France.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Rat
authors.forename: Ingrid
authors.initials: I
authors.lastname: Billaut-Laden
authors.forename: Delphine
authors.initials: D
authors.lastname: Allorge
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Lo-Guidice
authors.forename: Marie
authors.initials: M
authors.lastname: Tellier
authors.forename: Christelle
authors.initials: C
authors.lastname: Cauffiez
authors.forename: Nicolas
authors.initials: N
authors.lastname: Jonckheere
authors.forename: Isabelle
authors.initials: I
authors.lastname: van Seuningen
authors.forename: Michel
authors.initials: M
authors.lastname: Lhermitte
authors.forename: Antonio
authors.initials: A
authors.lastname: Romano
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Guéant
authors.forename: Franck
authors.initials: F
authors.lastname: Broly
mesh_terms: D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics*; D006801:Humans; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D018807:Polymorphism, Single-Stranded Conformational; D000072516:Retinoic Acid 4-Hydroxylase; D016135:Spinal Dysraphism / Q000201:enzymology* / Q000235:genetics; D014212:Tretinoin / Q000378:metabolism*
chemical_list: D014212:Tretinoin; D003577:Cytochrome P-450 Enzyme System; C000607079:CYP26B1 protein, human; C000607082:Cyp26b1 protein, rat; D000072516:Retinoic Acid 4-Hydroxylase