title: Thyroxine-Based Screening for Congenital Hypothyroidism in Neonates with Down Syndrome.
abstract: To ascertain whether thyroxine (T4)-based screening programs for congenital hypothyroidism (initial measurement of total T4 [tT4] followed by thyroid stimulating hormone [TSH] measurement in patients with tT4 <10th percentile) identifies congenital hypothyroidism in all neonates with Down syndrome.
  
  
  
  Retrospective cohort study of 159 neonates with Down syndrome, born during the period 1998-2007 were included. Screening test results were compared with those of the general population. All primary care physicians of these infants were contacted and infants' thyroid status verified.
  
  
  
  tT4 concentrations in children with Down syndrome were significantly lower, and TSH higher than those in the general population; tT4 concentrations did not correlate with screening TSH concentrations. Twenty children with Down syndrome were treated with L-thyroxin within the first month of life although only 10 babies had been identified by the routine screening test.
  
  
  
  T4-based screening does not identify many cases of congenital hypothyroidism in neonates with Down syndrome. We recommend that neonates with Down syndrome be screened by simultaneous measurements of both tT4 and TSH.
authors.affiliation: Department of Pediatrics, Shaare Zedek Medical Center, Affiliated with the Hebrew University School of Medicine, Jerusalem, Israel.
authors.forename: Ira
authors.initials: I
authors.lastname: Erlichman
authors.affiliation: Department of Neonatology, Shaare Zedek Medical Center, Affiliated with the Hebrew University School of Medicine, Jerusalem, Israel.
authors.forename: Francis B
authors.initials: FB
authors.lastname: Mimouni
authors.affiliation: Department of Pediatrics, Shaare Zedek Medical Center, Affiliated with the Hebrew University School of Medicine, Jerusalem, Israel.
authors.forename: Matityahu
authors.initials: M
authors.lastname: Erlichman
authors.affiliation: Department of Neonatology, Shaare Zedek Medical Center, Affiliated with the Hebrew University School of Medicine, Jerusalem, Israel. Electronic address: schimmel@szmc.org.il.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Schimmel
mesh_terms: D016022:Case-Control Studies; D015331:Cohort Studies; D003409:Congenital Hypothyroidism / Q000175:diagnosis* / Q000188:drug therapy; D004314:Down Syndrome / Q000150:complications*; D020249:Hormone Replacement Therapy; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D015997:Neonatal Screening / Q000379:methods*; D012189:Retrospective Studies; D013960:Thyroid Function Tests; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood* / Q000627:therapeutic use
chemical_list: D013972:Thyrotropin; D013974:Thyroxine
keywords: Down syndrome; T4; TSH; congenital hypothyroidism