title: Type 2 deiodinase Thr92Ala polymorphism is associated with disrupted placental activity but not with dysglycemia or adverse gestational outcomes: a genetic association study.
abstract: OBJECTIVE
  To study whether the D2 Thr92Ala polymorphism-a genetic marker that is associated with reduced thyroid type 2 deiodinase (D2) activity, increased insulin resistance, and risk for type 2 diabetes-is associated with disrupted placental D2 activity and with glycemic control and gestational outcomes.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Tertiary hospital in Brazil.
  
  
  METHODS
  Consecutive singleton-pregnancy patients, 18-45 years old.
  
  
  METHODS
  Clinical examination and genotyping of the D2 Thr92Ala polymorphism, with placental samples collected and assayed for D2 mRNA and activity.
  
  
  METHODS
  Glucose homeostasis and gestational outcomes.
  
  
  RESULTS
  A total of 294 patients were included in the study. The clinical and laboratory characteristics were similar among the D2 genotypes. No differences were observed in D2 placental mRNA levels, but D2 activity was decreased in patients with the Ala92Ala genotype (0.35 ± 0.15 vs. 1.96 ± 1.02 fmol/mg/min.). Newborn serum thyroid-stimulating hormone levels (TSHneo) did not differ according to maternal D2 Thr92Ala genotype. Also, maternal glucose control, insulin resistance evaluated by the homeostasis model assessment (HOMA-IR), and gestational outcomes did not differ across D2 genotypes.
  
  
  CONCLUSIONS
  The D2 Ala92Ala genotype is associated with reduced placental D2 activity but is not associated with dysglycemia, increased insulin resistance, or worse gestational outcomes.
authors.affiliation: Thyroid Section, Endocrine Division, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. Electronic address: jmdora@gmail.com.
authors.forename: José Miguel
authors.initials: JM
authors.lastname: Dora
authors.affiliation: Thyroid Section, Endocrine Division, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Simone M
authors.initials: SM
authors.lastname: Wajner
authors.affiliation: Thyroid Section, Endocrine Division, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Juliano Dalla
authors.initials: JD
authors.lastname: Costa
authors.affiliation: Thyroid Section, Endocrine Division, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Rafaela Vanin
authors.initials: RV
authors.lastname: Pinto Ribeiro
authors.affiliation: Thyroid Section, Endocrine Division, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Leonardo Barbosa
authors.initials: LB
authors.lastname: Leiria
authors.affiliation: Thyroid Section, Endocrine Division, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Mariah G
authors.initials: MG
authors.lastname: Lopes
authors.affiliation: Thyroid Section, Endocrine Division, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Aline
authors.initials: A
authors.lastname: Vitali da Silva
authors.affiliation: Thyroid Section, Endocrine Division, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Daisy
authors.initials: D
authors.lastname: Crispim
authors.affiliation: Thyroid Section, Endocrine Division, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Ana Luiza
authors.initials: AL
authors.lastname: Maia
mesh_terms: D000293:Adolescent; D000328:Adult; D000409:Alanine / Q000235:genetics; D001786:Blood Glucose / Q000235:genetics* / Q000378:metabolism; D003430:Cross-Sectional Studies; D005260:Female; D056726:Genetic Association Studies / Q000379:methods*; D006801:Humans; D007231:Infant, Newborn; D007333:Insulin Resistance / Q000502:physiology*; D007453:Iodide Peroxidase / Q000235:genetics*; D008875:Middle Aged; D010920:Placenta / Q000502:physiology*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000453:epidemiology; D013912:Threonine / Q000235:genetics; D055815:Young Adult; D000097564:Iodothyronine Deiodinase Type II
chemical_list: D000409:Alanine; D001786:Blood Glucose; D007453:Iodide Peroxidase; D013912:Threonine; D000097564:Iodothyronine Deiodinase Type II
keywords: Glucose homeostasis; Thr92Ala polymorphism; insulin resistance; iodothyronine deiodinase type II; pregnancy