title: IGF-I levels in prepubertal and pubertal children with Down syndrome.
abstract: BACKGROUND
  Growth retardation is a main feature of Down syndrome but it is still unclear whether an alteration of the GH/IGF-I axis is present in this condition. Concerning IGF-I levels, they have been found reduced by some authors but normal by others.
  
  
  METHODS
  On these bases, IGF-I levels have been assessed from prepubertal to late pubertal stages of gonadal maturation in a large group of children and adolescents with Down syndrome (DS, 68 M, 45 F, 12.5 +/- 0.6 yr; prepubertal n = 39, pubertal n = 74) with those in a group of normal children and adolescents (NS, 75 M, 87 F; 11.1 +/- 0.4 yr; prepubertal n = 94, pubertal n = 68).
  
  
  RESULTS
  Within each group, IGF-I levels were gender-independent while showed age-related variations with positive association with pubertal stage--peaking up in pubertal stage IV--(DS: r = 0.6, NS: r = 0.4, both p < 0.0001) and testosterone (DS: r = 0.6, NS: r = 0.5, p < 0.001) or estradiol (DS: r = 0.6, NS: r = 0.5, p < 0.001) levels. Considering whole groups, mean IGF-I levels in DS were slightly but significantly lower than those in NS (257.9 +/- 12.5 vs 310.8 +/- 12.6 micrograms/l, p < 0.02). Analyzing individual IGF-I levels in DS with respect to normal ranges per pubertal stage, more than 85% of IGF-I levels resulted within the normal limits. These results demonstrate that IGF-I levels in DS patients are generally within the normal range--though a slight reduction of mean IGF-I levels is present--and follow normal age-related variations with clear cut increase at puberty and positive association with gonadal steroid levels.
  
  
  CONCLUSIONS
  This evidence points toward the need to clarify the GH/IGF-I axis function and activity in DS patients.
authors.affiliation: Department of Pediatrics, Oasi Institute (IRCCS), Troina, Enna.
authors.forename: L
authors.initials: L
authors.lastname: Ragusa
authors.forename: M R
authors.initials: MR
authors.lastname: Valetto
authors.forename: C
authors.initials: C
authors.lastname: Proto
authors.forename: A
authors.initials: A
authors.lastname: Alberti
authors.forename: C
authors.initials: C
authors.lastname: Romano
authors.forename: A
authors.initials: A
authors.lastname: Rossodivita
authors.forename: G
authors.initials: G
authors.lastname: Corneli
authors.forename: C
authors.initials: C
authors.lastname: Baffoni
authors.forename: F
authors.initials: F
authors.lastname: Lanfranco
authors.forename: G
authors.initials: G
authors.lastname: Aimaretti
authors.forename: F
authors.initials: F
authors.lastname: Colabucci
authors.forename: E
authors.initials: E
authors.lastname: Ghigo
mesh_terms: D015415:Biomarkers / Q000097:blood; D002648:Child; D004314:Down Syndrome / Q000097:blood*; D005260:Female; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D011627:Puberty / Q000097:blood*
chemical_list: D015415:Biomarkers; D007334:Insulin-Like Growth Factor I