title: Early assessment of hypothalamic-pituitary-gonadal function in patients with congenital hypothyroidism of central origin.
abstract: BACKGROUND
  Early recognition of gonadotropic dysfunction could enable well-timed growth and maturation and prevent damage to gonads and external genitalia. The adaptation of the Dutch neonatal screening program for congenital hypothyroidism in the mid 1990s resulted in enhanced detection of congenital hypothyroidism of central origin (CH-C), with high likelihood of multiple pituitary hormone deficiency, including gonadotropin (Gn) deficiency.
  
  
  OBJECTIVE
  We analyzed GnRH test results and baseline Gn and sex hormone measurements in 15 infants with CH-C to examine these diagnostic tools for assessment of the integrity of the hypothalamus-pituitary-gonad axis in young infants.
  
  
  METHODS
  In a nationwide prospective study (1994-1996), patients were referred to our department if neonatal CH screening results were indicative of CH-C. When CH-C was confirmed, GnRH tests and baseline Gn and sex hormone measurements took place at the age of 3 months, when euthyroid status had been accomplished by T4 supplementation, and if necessary, cortisol supplementation was installed.
  
  
  METHODS
  The study took place at the Department of Pediatric Endocrinology, Emma Children's Hospital, Academic Medical Center, University of Amsterdam (referral center).
  
  
  METHODS
  The study included 15 neonates (five girls and 10 boys) with CH-C, detected by neonatal screening, in whom investigation of the hypothalamus-pituitary-gonad axis could be performed at 3 months of age.
  
  
  METHODS
  Results of GnRH tests and baseline Gn and sex hormone measurements were assessed.
  
  
  RESULTS
  GnRH tests at 3 months of age showed a pattern indicative of endogenous GnRH stimulation in nine infants and a blunted response in six. Baseline Gn and sex hormone concentrations except estradiol (P = 0.053) were significantly different between responders and nonresponders.
  
  
  CONCLUSIONS
  The GnRH test and baseline measurements of Gn and sex hormone serum concentrations at 3 months of age are promising options in the assessment of hypothalamic-pituitary-gonadal function in infants with CH-C of both sexes.
authors.affiliation: Department of Pediatric Endocrinology, Emma Children's Hospital, G8-205, Academic Medical Center, University of Amsterdam, PO Box 22700, 1100 DE Amsterdam, The Netherlands. tijn1@planet.nl
authors.forename: David A
authors.initials: DA
authors.lastname: van Tijn
authors.forename: Eelco J
authors.initials: EJ
authors.lastname: Schroor
authors.forename: Henriette A
authors.initials: HA
authors.lastname: Delemarre-van de Waal
authors.forename: Jan J M
authors.initials: JJ
authors.lastname: de Vijlder
authors.forename: Thomas
authors.initials: T
authors.lastname: Vulsma
mesh_terms: D003409:Congenital Hypothyroidism / Q000503:physiopathology*; D004958:Estradiol / Q000097:blood; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D007987:Gonadotropin-Releasing Hormone; D006801:Humans; D007030:Hypothalamo-Hypophyseal System / Q000503:physiopathology*; D007223:Infant; D007231:Infant, Newborn; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D010913:Pituitary-Adrenal System / Q000503:physiopathology*; D011446:Prospective Studies; D013739:Testosterone / Q000097:blood
chemical_list: D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone; D004958:Estradiol; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone