title: A human ALDH1A2 gene variant is associated with increased newborn kidney size and serum retinoic acid.
abstract: Nephron number varies widely between 0.3 and 1.3 million per kidney in humans. During fetal life, the rate of nephrogenesis is influenced by local retinoic acid (RA) level such that even moderate maternal vitamin A deficiency limits the final nephron number in rodents. Inactivation of genes in the RA pathway causes renal agenesis in mice; however, the impact of retinoids on human kidney development is unknown. To resolve this, we tested for associations between variants of genes involved in RA metabolism (ALDH1A2, CYP26A1, and CYP26B1) and kidney size among normal newborns. Homozygosity for a common (1 in 5) variant, rs7169289(G), within an Sp1 transcription factor motif of the ALDH1A2 gene, showed a significant 22% increase in newborn kidney volume when adjusted for body surface area. Infants bearing this allele had higher umbilical cord blood RA levels compared to those with homozygous wild-type ALDH1A2 rs7169289(A) alleles. Furthermore, the effect of the rs7169289(G) variant was evident in subgroups with or without a previously reported hypomorphic RET 1476(A) proto-oncogene allele that is critical in determining final nephron number. As maternal vitamin A deficiency is widespread in developing countries and may compromise availability of retinol for fetal RA synthesis, our study suggests that the ALDH1A2 rs7169289(G) variant might be protective for such individuals.
authors.affiliation: Department of Pediatrics, Montreal Children's Hospital Research Institute, McGill University, and Département de Médecine, Centre Hospitalier de l'Université de Montréal,Montreal, Quebec, Canada.
authors.forename: Reyhan
authors.initials: R
authors.lastname: El Kares
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Manolescu
authors.forename: Lajmi
authors.initials: L
authors.lastname: Lakhal-Chaieb
authors.forename: Alexandre
authors.initials: A
authors.lastname: Montpetit
authors.forename: Zhao
authors.initials: Z
authors.lastname: Zhang
authors.forename: Pangala V
authors.initials: PV
authors.lastname: Bhat
authors.forename: Paul
authors.initials: P
authors.lastname: Goodyer
mesh_terms: D000483:Alleles; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism*; D003906:Developing Countries; D005838:Genotype; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007668:Kidney / Q000378:metabolism; D007674:Kidney Diseases / Q000150:complications / Q000235:genetics; D009399:Nephrons / Q000196:embryology / Q000378:metabolism; D038081:Organogenesis / Q000235:genetics; D010088:Oxidoreductases / Q000235:genetics; D000090063:Proto-Oncogene Mas; D011519:Proto-Oncogenes; D000072516:Retinoic Acid 4-Hydroxylase; D012176:Retinoids / Q000235:genetics / Q000378:metabolism; D014212:Tretinoin / Q000378:metabolism*; D014801:Vitamin A / Q000235:genetics; D014802:Vitamin A Deficiency / Q000150:complications / Q000235:genetics
chemical_list: C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D012176:Retinoids; D014801:Vitamin A; D014212:Tretinoin; D003577:Cytochrome P-450 Enzyme System; D010088:Oxidoreductases; C000607079:CYP26B1 protein, human; C000607080:Cyp26a1 protein, mouse; C000607081:Cyp26b1 protein, mouse; D000072516:Retinoic Acid 4-Hydroxylase