title: Absence of GH-releasing hormone (GHRH) mutations in selected patients with isolated GH deficiency.
abstract: BACKGROUND
  Although numerous reports of mutations in GH1 and GHRHR (GHRH receptor) causing isolated GH deficiency (IGHD) have been published, mutations in GHRH itself have not been hitherto reported but are obvious candidates for GH deficiency.
  
  
  OBJECTIVE
  The aim of this study was to identify mutations in GHRH in a large cohort of patients with IGHD.
  
  
  METHODS
  DNA was isolated from 151 patients diagnosed with IGHD at national and international centers. Seventy-two patients fulfilled all the following criteria: severe short stature (height sd score ≤ -2.5), low peak GH after stimulation (peak ≤ 5 ng/ml), eutopic posterior pituitary lobe, and absence of mutations in GH1 and GHRHR and therefore were strong candidates for GHRH mutations. The coding sequence and splice sites of GHRH were amplified by PCR with intronic primers and sequenced.
  
  
  RESULTS
  In five of 151 patients (four of 42 from Brazil), the GHRH c.223 C>T, p.L75F change was identified in heterozygosity. This variant has been previously reported as a polymorphism and is more frequent in African than European and Asian populations. Six allelic variants (five novel) that do not predict change of amino acids or splice sites were identified in five patients: c.147 C>T, p.S49S, IVS1 -70 G>A, IVS1 -74 T>C, IVS3 -47 del1, and IVS3 +7 G>A /IVS3+41 G>A. No functional mutations were found in this cohort.
  
  
  CONCLUSIONS
  GHRH mutations were not identified in a selected cohort of patients with IGHD, suggesting that, if they exist, they may be an extremely rare cause of IGHD. Other, as-yet-unidentified genetic factors may be implicated in the genetic etiology of IGHD in our cohort.
authors.affiliation: Unidade de Endocrinologia do Desenvolvimento, Laboratorio de Hormonios e Genetica Molecular, LIM/42, Disciplina de Endocrinologia, Hospital das Clinicas, Faculdade de Medicina da Universidade de São Paulo, São Paulo 05403-900, Brazil.
authors.forename: Marcela M
authors.initials: MM
authors.lastname: França
authors.forename: Alexander A L
authors.initials: AA
authors.lastname: Jorge
authors.forename: Kyriaki S
authors.initials: KS
authors.lastname: Alatzoglou
authors.forename: Luciani R S
authors.initials: LR
authors.lastname: Carvalho
authors.forename: Berenice B
authors.initials: BB
authors.lastname: Mendonca
authors.forename: Laura
authors.initials: L
authors.lastname: Audi
authors.forename: Antonio
authors.initials: A
authors.lastname: Carrascosa
authors.forename: Mehul T
authors.initials: MT
authors.lastname: Dattani
authors.forename: Ivo J P
authors.initials: IJ
authors.lastname: Arnhold
mesh_terms: D000328:Adult; D000483:Alleles; D015331:Cohort Studies; D005260:Female; D056726:Genetic Association Studies; D013007:Growth Hormone-Releasing Hormone / Q000235:genetics*; D019382:Human Growth Hormone / Q000172:deficiency* / Q000235:genetics*; D006801:Humans; D008297:Male; D009154:Mutation; D011110:Polymorphism, Genetic
chemical_list: D019382:Human Growth Hormone; D013007:Growth Hormone-Releasing Hormone