FGFR1 and PROKR2 rare variants found in patients with combined pituitary hormone deficiencies.

The genetic aetiology of congenital hypopituitarism (CH) is not entirely elucidated. FGFR1 and PROKR2 loss-of-function mutations are classically involved in hypogonadotrophic hypogonadism (HH), however, due to the clinical and genetic overlap of HH and CH; these genes may also be involved in the pathogenesis of CH. Using a candidate gene approach, we screened 156 Brazilian patients with combined pituitary hormone deficiencies (CPHD) for loss-of-function mutations in FGFR1 and PROKR2. We identified three FGFR1 variants (p.Arg448Trp, p.Ser107Leu and p.Pro772Ser) in four unrelated patients (two males) and two PROKR2 variants (p.Arg85Cys and p.Arg248Glu) in two unrelated female patients. Five of the six patients harbouring the variants had a first-degree relative that was an unaffected carrier of it. Results of functional studies indicated that the new FGFR1 variant p.Arg448Trp is a loss-of-function variant, while p.Ser107Leu and p.Pro772Ser present signalling activity similar to the wild-type form. Regarding PROKR2 variants, results from previous functional studies indicated that p.Arg85Cys moderately compromises receptor signalling through both MAPK and Ca(2) (+) pathways while p.Arg248Glu decreases calcium mobilization but has normal MAPK activity. The presence of loss-of-function variants of FGFR1 and PROKR2 in our patients with CPHD is indicative of an adjuvant and/or modifier effect of these rare variants on the phenotype. The presence of the same variants in unaffected relatives implies that they cannot solely cause the phenotype. Other associated genetic and/or environmental modifiers may play a role in the aetiology of this condition

Genetic Predictors Of Long-term Response To Growth Hormone (gh) Therapy In Children With Gh Deficiency And Turner Syndrome: The Influence Of A Socs2 Polymorphism

Design and Patients: Genotypes were correlated with adult height data of 65 Turner syndrome (TS) and 47GHdeficiency (GHD) patients treated with rhGH, by multiple linear regressions. Generalized multifactor dimensionality reduction was used to evaluate gene-gene interactions.Background: There is great interindividual variability in the response to GH therapy. Ascertaining genetic factors can improve the accuracy of growth response predictions. Suppressor of cytokine signaling (SOCS)-2 is an intracellular negative regulator of GH receptor (GHR) signaling. CopyrightObjective: The objective of the study was to assess the influence of a SOCS2 polymorphism (rs3782415) and its interactive effect with GHR exon 3 and -202 A/C IGFBP3 (rs2854744) polymorphisms on adult height of patients treated with recombinant human GH (rhGH).Results: Baseline clinical data were indistinguishable among patients with different genotypes. Adult height SD scores of patients with at least one SOCS2 single-nucleotide polymorphism rs3782415-C were 0.7 higher than those homozygous for the T allele (P < .001). SOCS2 (P = .003), GHR-exon 3 (P=.016) and-202 A/C IGFBP3 (P=.013) polymorphisms, together with clinical factors accounted for 58% of the variability in adult height and 82% of the total height SD score gain. Patients harboring any two negative genotypes in these three different loci (homozygosity for SOCS2 T allele; the GHR exon 3 full-length allele and/or the -202C-IGFBP3 allele) were more likely to achieve an adult height at the lower quartile (odds ratio of 13.3; 95% confidence interval of 3.2-54.2, P = .0001).Conclusion: The SOCS2 polymorphism (rs3782415) has an influence on the adult height of children with TS andGHDafter long-term rhGH therapy. Polymorphisms located inGHR, IGFBP3, and SOCS2 loci have an influence on the growth outcomes of TS and GHD patients treated with rhGH. The use of these genetic markers could identify among rhGH-treated patients those who are genetically predisposed to have less favorable outcomes.999E1808E1813Geffner, M.E., Dunger, D.B., Future directions: Growth prediction models (2007) Horm Res., 68, pp. 51-56Flores-Morales, A., Greenhalgh, C.J., Norstedt, G., Rico-Bautista, E., Negative regulation of growth hormone receptor signaling (2006) Mol Endocrinol., 20, pp. 241-253Greenhalgh, C.J., Rico-Bautista, E., Lorentzon, M., SOCS2 negatively regulates growth hormone action in vitro and in vivo (2005) J Clin Invest., 115, pp. 397-406Wassenaar, M.J., Dekkers, O.M., Pereira, A.M., Impact of the exon 3-deleted GH receptor polymorphism on baseline height and the growth response to recombinant human growth hormone therapy in growth hormone deficient(GHD)andnon-GHDchildren with short stature: A systematic review and meta-analysis (2009) J Clin Endocrinol Metab., 94, pp. 3721-3730Renehan, A.G., Solomon, M., Zwahlen, M., Growth hormone receptor polymorphism and growth hormone therapy response in children: A Bayesian meta-analysis (2012) AmJ Epidemiol., 175, pp. 867-877Costalonga, E.F., Antonini, S.R., Guerra-Junior, G., Mendonca, B.B., Arnhold, I.J., Jorge, A.A., The-202 A allele of insulin-like growth factor binding protein-3 (IGFBP3) promoter polymorphism is associated with higher IGFBP-3 serum levels and better growth response to growth hormone treatment in patients with severe growth hormone deficiency (2009) J Clin Endocrinol Metab., 94, pp. 588-595Braz, A.F., Costalonga, E.F., Montenegro, L.R., The interactive effect of GHR-exon 3 and-202 A/C IGFBP3 polymorphisms on rhGH responsiveness and treatment outcomes in patients with Turner syndrome (2012) J Clin Endocrinol Metab., 97, pp. E671-E677Weedon, M.N., Lango, H., Lindgren, C.M., Genome-wide association analysis identifies 20 loci that influence adult height (2008) Nat Genet., 40, pp. 575-583Gudbjartsson, D.F., Walters, G.B., Thorleifsson, G., Manysequence variants affecting diversity of adult human height (2008) Nat Genet., 40, pp. 609-615Chan, Y., Holmen, O.L., Dauber, A., Common variants show predicted polygenic effects on height in the tails of the distribution, except in extremely short individuals (2011) PLoS Genet., 7, p. e1002439Lou, X.Y., Chen, G.B., Yan, L., A generalized combinatorial approach for detecting gene-by-gene and gene-by-environment interactions with application to nicotine dependence (2007) Am J Hum Genet., 80, pp. 1125-1137Lango Allen, H., Estrada, K., Lettre, G., Hundreds of variants clustered in genomic loci and biological pathways affect human height (2010) Nature., 467, pp. 832-838Lanktree, M.B., Guo, Y., Murtaza, M., Meta-analysis of dense genecentric association studies reveals common and uncommon variants associated with height (2011) Am J Hum Genet., 88, pp. 6-18Ranke, M.B., Lindberg, A., Albertsson-Wikland, K., Wilton, P., Price, D.A., Reiter, E.O., Increased response, but lower responsiveness, to growth hormone (GH) in very young children (aged 0-3 years) with idiopathicGHDeficiency: Analysis of data from KIGS (2005) J Clin Endocrinol Metab., 90, pp. 1966-1971Ranke, M.B., Lindberg, A., Chatelain, P., Prediction of long-term response to recombinant human growth hormone in Turner syndrome: Development and validation of mathematical models. KIGS International Board. Kabi International Growth Study (2000) J Clin Endocrinol Metab., 85, pp. 4212-4218Ranke, M.B., Lindberg, A., Cowell, C.T., Prediction of response to growth hormone treatment in short children born small for gestational age: Analysis of data from KIGS (Pharmacia International Growth Database) (2003) J Clin Endocrinol Metab., 88, pp. 125-131Clayton, P., Chatelain, P., Tato, L., Apharmacogenomic approach to the treatment of children withGHdeficiency or Turner syndrome (2013) Eur J Endocrinol., 169, pp. 277-289Stevens, A., Clayton, P., Tato, L., Pharmacogenomics of insulinlike growth factor-I generation during GH treatment in children with GH deficiency or Turner syndrome (2014) Pharmacogenomics J., 14, pp. 54-6

Study of major genetic factors involved in pituitary tumorigenesis and their impact on clinical and biological characteristics of sporadic somatotropinomas and non-functioning pituitary adenomas

Genetic and functional aberrations of guanine nucleotide-binding protein, alpha stimulating (GNAS), aryl hydrocarbon receptor interacting protein (AIP), and pituitary tumor transforming gene (PTTG) are among the most prominent events in pituitary tumorigenesis. A cohort of Brazilian patients with somatotropinomas (n=41) and non-functioning pituitary adenomas (NFPA, n=21) from a single tertiary-referral center were evaluated for GNAS and AIP mutations and gene expression of AIP and PTTG. Results were compared to the clinical and biological (Ki67 and p53 expression) characteristics of tumors and their response to therapy, if applicable. Genetic analysis revealed that 27% of somatotropinomas and 4.8% of NFPA harbored GNAS mutations (P=0.05). However, no differences were observed in clinical characteristics, tumor extension, response to somatostatin analog therapy, hormonal/surgical remission rates, Ki67 index, and p53 expression between mutated and non-mutated somatotropinomas patients. PTTG overexpression (RQ mean=10.6, min=4.39, max=11.9) and AIP underexpression (RQ mean=0.56, min=0.46-max=0.92) were found in virtually all cases without a statistically significant relationship with clinical and biological tumor features. No patients exhibited somatic or germline pathogenic AIP mutations. In conclusion, mutations in GNAS and abnormal PTTG and AIP expression had no impact on tumor features and treatment outcomes in this cohort. Our data support some previous studies and point to the need for further investigations, probably involving epigenetic and transcriptome analysis, to improve our understanding of pituitary tumor behavior

Supplementary Material for: GH-Releasing Hormone Receptor Gene: A Novel Splice-Disrupting Mutation and Study of Founder Effects

<b><i>Background:</i></b> Mutations in GH-releasing hormone receptor gene <i>(GHRHR)</i> are emerging as the most common cause of autosomal recessive isolated GH deficiency (IGHD). <b><i>Objective:</i></b> To search for <i>GHRHR</i> mutations in patients with familial or sporadic IGHD and to investigate founder effects in recurring mutations. <b><i>Methods:</i></b> The coding region of <i>GHRHR</i> was entirely amplified and sequenced from DNA of 18 patients with IGHD (16 unrelated) with topic posterior pituitary lobe on MRI. Haplotypes containing promoter SNPs and microsatellites flanking <i>GHRHR</i> were analyzed in patients with c.57+1G>A (IVS1+1G>A) mutation of our previously published kindred and also a Brazilian patient and 2 previously reported Japanese sisters with c.1146G>A (p.E382E) mutation. <b><i>Results:</i></b> A novel homozygous intronic <i>GHRHR</i> c.752-1G>A (IVS7-1G>A) mutation, predicting loss of the constitutive splice acceptor site, was identified in two siblings with IGHD. A compound heterozygous c.[57+1G>A];[1146G>A] and a heterozygous c.527C>T (p.A176V) were found in two sporadic cases. Haplotype analysis provided evidence for a founder effect for the c.57+1G>A mutation and independent recurrence for the c.1146G>A mutation. <b><i>Conclusion:</i></b> We report a novel splice-disrupting mutation in <i>GHRHR</i> in 2 siblings and provide evidence that all c.57+1G>A (IVS1+1G>A) mutant chromosomes have the same haplotype ancestor, indicating the occurrence of a founder effect in Brazilian patients with IGHD