Isolated Growth Hormone Deficiency Research Articles

Morphological changes in the central sulcus of children with isolated growth hormone deficiency versus idiopathic short stature.

In this study, the morphological changes in the central sulcus between children with isolated growth hormone deficiency (IGHD) and those with idiopathic short stature (ISS) were analyzed. Thirty children with IGHD (peak growth hormone<5µg/L) and 30 children with ISS (peak growth hormone>10.0µg/L) were included. Morphological measurements of the central sulcus were obtained from T1-weighted MRIs using BrainVISA, including the average sulcal width, maximum depth, average depth, top length, bottom length, and depth position-based profiles (DPPs). The bilateral average width of the central sulci was significantly wider, while the left maximum depth and right average depth of the central sulcus were significantly smaller, in children with IGHD than in children with ISS. There were no significant differences in the right maximum depth, left average depth, or bilateral top length and bottom length of the central sulcus between groups. The DPPs of the middle part of both central sulci (corresponding to the hand motor activation area) and the inferior part of the right central sulcus (corresponding to the oral movement area) near the Sylvian fissure were significantly smaller in children with IGHD than in controls before false discovery rate (FDR) correction. However, all the above significant DPP sites disappeared after FDR correction. There were significant morphological changes in the three-dimensional structure of the central sulcus in children with IGHD, which were the outcome of other more essential cortical or subcortical changes, resulting in their relatively slower development in motor, cognitive, and linguistic functional performance.

Short Stature Due to Isolated Growth Hormone Deficiency—Case Report

Short stature is a common cause for addressing the endocrinologist. Growth hormone deficiency is estimated to occur in 1:4000 to 1:10,000 of small stature cases [1]. Identifying and treating these children is of high importance given the psycho-social implication of small stature. I present the case of a male teenager ages 15 years 10 months old who responded well to treatment, achieving the target genetic stature.

Mutations in LAMB2 are associated with albuminuria and optic nerve hypoplasia with hypopituitarism

CONTEXT Mutations in LAMB2, encoding the basement membrane protein, laminin β2, are associated with an autosomal recessive disorder characterized by congenital nephrotic syndrome, ocular abnormalities, and neurodevelopmental delay (Pierson syndrome). CASE DESCRIPTION This report describes a 12-year-old boy with short stature, visual impairment, and developmental delay who presented with macroscopic hematuria and albuminuria. He had isolated growth hormone deficiency, optic nerve hypoplasia, and a small anterior pituitary with corpus callosum dysgenesis on his cranial magnetic resonance imaging, thereby supporting a diagnosis of optic nerve hypoplasia syndrome. Renal histopathology revealed focal segmental glomerulosclerosis. Using next-generation sequencing on a targeted gene panel for steroid-resistant nephrotic syndrome, compound heterozygous missense mutations were identified in LAMB2 (c.737G>A p.Arg246Gln, c.3982G>C p.Gly1328Arg). Immunohistochemical analysis revealed reduced glomerular laminin β2 expression compared to control kidney and a thin basement membrane on electron microscopy. Laminin β2 is expressed during pituitary development and Lamb2-/- mice exhibit stunted growth, abnormal neural retinae, and here we show, abnormal parenchyma of the anterior pituitary gland. CONCLUSION We propose that patients with genetically undefined optic nerve hypoplasia syndrome should be screened for albuminuria and, if present, screened for mutations in LAMB2.

Structural basis for activation of the growth hormone-releasing hormone receptor

Growth hormone-releasing hormone (GHRH) regulates the secretion of growth hormone that virtually controls metabolism and growth of every tissue through its binding to the cognate receptor (GHRHR). Malfunction in GHRHR signaling is associated with abnormal growth, making GHRHR an attractive therapeutic target against dwarfism (e.g., isolated growth hormone deficiency, IGHD), gigantism, lipodystrophy and certain cancers. Here, we report the cryo-electron microscopy (cryo-EM) structure of the human GHRHR bound to its endogenous ligand and the stimulatory G protein at 2.6 Å. This high-resolution structure reveals a characteristic hormone recognition pattern of GHRH by GHRHR, where the α-helical GHRH forms an extensive and continuous network of interactions involving all the extracellular loops (ECLs), all the transmembrane (TM) helices except TM4, and the extracellular domain (ECD) of GHRHR, especially the N-terminus of GHRH that engages a broad set of specific interactions with the receptor. Mutagenesis and molecular dynamics (MD) simulations uncover detailed mechanisms by which IGHD-causing mutations lead to the impairment of GHRHR function. Our findings provide insights into the molecular basis of peptide recognition and receptor activation, thereby facilitating the development of structure-based drug discovery and precision medicine.

Disruption of the GHRH receptor and its impact on children and adults: The Itabaianinha syndrome.

Since 1994, we have been studying an extended kindred with 105 subjects (over 8 generations) residing in Itabaianinha County, in the Brazilian state of Sergipe, who have severe isolated GH deficiency (IGHD) due to a homozygous inactivating mutation (c.57 + 1G > A) in the GH releasing hormone (GHRH) receptor (GHRHR) gene. Most of these individuals have never received GH replacement therapy. They have low GH, and very low and often undetectable levels of serum IGF-I. Their principal physical findings are proportionate short stature, doll facies, high-pitched-voice, central obesity, wrinkled skin, and youthful hair with delayed pigmentation, and virtual absence of graying. The newborns from this cohort are of normal size, indicating that GH is not needed for intra-uterine growth. However, these IGHD individuals exhibit a myriad of phenotypic changes throughout the body, with a greater number of beneficial than harmful consequences. This GHRH signal disruption syndrome has been a valuable model to study the GH roles in body size and function. This reviews summarized the findings we have reported on this cohort.

Genetic spectrum and predictors of mutations in four known genes in Asian Indian patients with growth hormone deficiency and orthotopic posterior pituitary: an emphasis on regional genetic diversity.

Regional variation in prevalence of genetic mutations in growth hormone deficiency (GHD) is known. Study phenotype and prevalence of mutations in GH1, GHRHR, POU1F1, PROP1 genes in GHD cohort. One hundred and two patients {Isolated GHD (IGHD): 79; combined pituitary hormone deficiency (CPHD): 23} with orthotopic posterior pituitary were included. Auxologic, hormonal and radiological details were studied. All four genes were analysed in IGHD patients. POU1F1 and PROP1 were studied in CPHD patients. Of 102, 19.6% were familial cases. Height SDS, mean (SD) was - 5.14 (1.63). Peak GH, median (range) was 0.47ng/ml (0-6.59), 72.5% patients had anterior pituitary hypoplasia (APH). Twenty mutations (novel: 11) were found in 43.1% patients (n = 44, IGHD-36, CPHD-8). GHRHR mutations (n = 32, p.Glu72* = 24) were more common than GH1 mutations (n = 4) in IGHD cohort. POU1F1 mutations (n = 6) were more common than PROP1 mutations (n = 2) in CPHD cohort. With few exceptions, this prevalence pattern is contrary to most studies in world-literature. No patients with peak GH > 4ng/ml had mutations, signifying it as negative predictor. While many parameters were significant on univariate analysis, only positive family history and lower median peak GH levels were significant predictors of mutations on multivariate analysis in IGHD patients. At variance with world literature, we found reverse predominance of GHRHR over GH1 mutations, POU1F1 over PROP1 mutations and predominance of GHRHR p.Glu72* mutations thus re-affirming the regional diversity in GHD genetics. We report positive and negative predictors of mutations in GHD.

Evaluation of the Final Adult Height and Its Determinants in Patients with Growth Hormone Deficiency: A Single-centre Experience from the South-Eastern Region of Turkey

Objective:The aim was to determine the final adult height (FAH) achieved by recombinant human growth hormone (rhGH) treatment, the factors affecting FAH and the success of attaining the genetic potential.Methods:Data of 133 patients treated with rhGH therapy were reviewed retrospectively. Patients were grouped according to diagnosis, either isolated GH deficiency (IGHD) or multiple pituitary hormone deficiency (MPHD), and by sex, and pubertal status at the beginning of treatment.Results:The mean age of initiation of treatment was 12.3±2.18 years, and the mean duration of rhGH treatment was 3.65±1.5 years. The mean height standard deviation score (SDS) at diagnosis was -3.11±0.75 SD. All patients received a standardized GH dose of 0.033 mg/kg/day. Mean FAH-SDS was -1.8±0.77 and delta height-SDS (the change in height SDS between the beginning and end of treatment) was 1.28±0.94 SD. FAH-SDS was -1.79±0.86 SD in males; -1.82±0.64 in females (p=0.857); -1.94±0.71 at the beginning of treatment in pubertal patients and -1.68±0.81 in prepubertal patients (p=0.056); -1.84±0.89 in patients with IGHD and -0.47±0.2 in patients with MPHD (p˃0.05). In multiple regression analysis, First year delta height-SDS was the most predictive factor for both FAH-SDS and delta height-SDS.Conclusion:The majority of our patients achieved a final height compatible with their genetic potential as well as population standards when treated with rhGH even having started at a relatively late age. First year delta height-SDS was a predictive factor for FAH.

Morphological changes of the cerebral cortex between children with isolated growth hormone deficiency and idiopathic short stature

The growth hormone (GH)-insulin-like growth factor-I (IGF-I) axis plays an important role in normal brain development, and GH deficiency inevitably affects the growth of the cerebral cortex. This study was designed to analyze morphological differences in gray matter volume, cortical surface area, and gray matter thickness between children with isolated growth hormone deficiency (IGHD) and children with idiopathic short stature (ISS). Twenty-four children with IGHD (mean age 9.42 years, peak GH < 5 μg/l) and 24 controls with ISS (mean age 9.21 years, peak GH > 10 μg/l) were included. High-resolution three-dimensional T1-weighted MRIs were acquired at participants’ first visit. Measurements of gray matter volume, cortical surface area and gray matter thickness were obtained using FreeSurfer. The total and regional differences between groups were statistically analyzed. Correlations between the FreeSurfer results and GH and IGF-I levels were also obtained. The gray matter volume, cortical surface area and gray matter thickness of the total brain and of the bilateral hemispheres of children with IGHD were significantly smaller than those of children with ISS (all P values < 0.05). All the measurements had similar cortical distributions between groups but varied across regions. Cortical regions with significant differences in the mean gray matter volume and surface area were mainly distributed around the bilateral central sulci and the lateral and basal parts of the temporal lobes (all P values < 0.05). There were negative correlations between gray matter volume, cortical surface area and GH levels, and the right hemispheric and total cortical surface area correlated significantly with GH levels (all P values < 0.05) in children with IGHD. There were significant positive correlations between gray matter volume, cortical surface area and IGF-I levels (all P values < 0.05) in both groups, except for in left hemispheric gray matter volume in children with ISS. Children with IGHD have significant morphological changes in the cerebral cortex, which were partially influenced by GH and IGF-I levels. These cortical changes may be related to deficits in their relatively slower development in intelligence, motor performance, and other functions.

Identification of novel candidate pathogenic genes in pituitary stalk interruption syndrome by whole-exome sequencing.

Pituitary stalk interruption syndrome (PSIS) is a type of congenital malformation of the anterior pituitary, which leads to isolated growth hormone deficiency or multiple hypothalamic‐pituitary deficiencies. Many genetic factors have been explored, but they only account for a minority of the genetic aetiology. To identify novel PSIS pathogenic genes, we conducted whole‐exome sequencing with 59 sporadic PSIS patients, followed by filtering gene panels involved in pituitary development, holoprosencephaly and midline abnormality. A total of 81 heterozygous variants, distributed among 59 genes, were identified in 50 patients, with 31 patients carrying polygenic variants. Fourteen of the 59 pathogenic genes clustered to the Hedgehog pathway. Of them, PTCH1 and PTCH2, inhibitors of Hedgehog signalling, showed the most frequent heterozygous mutations (22%, seven missense and one frameshift mutations were identified in 13 patients). Moreover, five novel heterozygous null variants in genes including PTCH2 (p.S391fs, combined with p.L104P), Hedgehog acyltransferase (p.R280X, de novo), MAPK3 (p.H50fs), EGR4 (p.G22fs, combined with LHX4 p.S263N) and SPG11 (p.Q1624X), which lead to truncated proteins, were identified. In conclusion, genetic mutations in the Hedgehog signalling pathway might underlie the complex polygenic background of PSIS, and the findings of our study could extend the understanding of PSIS pathogenic genes.

Questioning the Value of Brain Magnetic Resonance Imaging in the Evaluation of Children with Isolated Growth Hormone Deficiency

Background: Isolated growth hormone deficiency (IGHD) is a relatively common disorder. Current diagnostic protocol requires a brain magnetic resonance imaging (MRI) study of the hypothalamus and the hypophysis to determine the cause after establishment of the diagnosis. This study aimed to examine the yield of brain MRI in the evaluation of children with IGHD and to define clinical and laboratory parameters that justify its performance. Methods: A retrospective chart review of all children (<18 years) diagnosed with IGHD was conducted at 3 pediatric endocrinology units between 2008 and 2018. Results: The study included 192 children (107 boys) with confirmed IGHD. The mean age ± standard deviation (SD) at diagnosis was 8.2 ± 3.7 years (median 8.5 years, range 0.8–15.9). The mean height SD score (SDS) at diagnosis was –2.25 ± 0.73. The mean height deficit SDS (defined as the difference between height SDS at diagnosis and mid-parental height SDS) was –1.7 ± 0.9. Fifteen children (7.8%) had pathological MRI findings. No space-occupying lesion was detected. Children with pathological MRIs had greater height deficit SDS and lower peak growth hormone levels on provocative tests compared to children with normal MRIs: –2.3 ± 1.2 vs. –1.6 ± 0.8 (p = 0.02) and 4.4 ± 1.9 vs. 5.7 ± 1.3 (p = 0.01), respectively. Conclusion: Our preliminary data indicate that most brain MRIs performed for routine evaluation of children with IGHD are not essential for determining cause. Further studies with larger cohorts are needed in order to validate this proposed revision of current protocols.

Discriminatory performance of insulin-like growth factor 1 and insulin-like growth factor binding protein-3 by correlating values to chronological age, bone age, and pubertal status for diagnosis of isolated growth hormone deficiency.

PurposeThe discriminatory performance of insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein-3 (IGFBP-3) was investigated by correlating their values with chronological age (CA), bone age (BA), and pubertal status (PS) for diagnosis of isolated growth hormone deficiency (IGHD).MethodsWe evaluated IGF-1 and IGFBP-3 levels in 310 short-stature subjects subdivided into 2 groups: IGHD (n=31) and non-IGHD (n=279). IGF-1 and IGFBP-3 were assayed using immune-radiometric assay and transformed into standard deviation score (SDS) according to CA, BA, and PS.ResultsThe highest sensitivity was found in IGF-1-SDS for CA and IGFBP-3-SDS for CA (22.6% and 30.0%, respectively). The highest specificity was found in IGF-1-SDS for PS and IGFBP-3-SDS for PS (98.2% and 94.4%, respectively). Groups with the highest positive predictive values were IGF-1-SDS for BA and IGFBP-3-SDS for BA (10.9% and 5.1%, respectively). Highest negative predictive values were seen in IGF-1-SDS for CA and IGFBP-3-SDS for CA (98.4% and 98.4%, respectively).ConclusionsIGF-1-SDS for CA, instead of IGF-1-SDS for BA or PS, could be used as a standard variable for IGHD screening. The sufficiently high specificity of IGF-1-SDS for PS suggests that this value is a useful tool for identification of IGHD.

Long-term mortality after childhood growth hormone treatment: the SAGhE cohort study

Recombinant human growth hormone has been used for more than 30 years and its indications have increased worldwide. There is concern that this treatment might increase mortality, but published data are scarce. We present data from the entire dataset of all eight countries of the Safety and Appropriateness of Growth hormone treatments in Europe (SAGhE) consortium, with the aim of studying long-term overall and cause-specific mortality in young adult patients treated with recombinant human growth hormone during childhood and relating this to the underlying diagnosis. This cohort study was done in eight European countries (Belgium, France, Germany, Italy, The Netherlands, Sweden, Switzerland, and the UK). Patients were classified a priori based on pre-treatment perceived mortality risk from their underlying disease and followed up for cause-specific mortality. Person-years at risk of mortality and expected rates from general population data were used to calculate standardised mortality ratios (SMRs). The cohort comprised 24 232 patients treated with recombinant human growth hormone during childhood, with more than 400 000 patient-years of follow-up. In low-risk patients with isolated growth hormone deficiency or idiopathic short stature, all-cause mortality was not significantly increased (SMR 1·1, 95% CI 0·9-1·3). In children born small for gestational age, all-cause mortality was significantly increased when analysed for all countries (SMR 1·5, CI 1·1-1·9), but this result was driven by the French subcohort. In patients at moderate or high risk, mortality was increased (SMR 3·8, 3·3-4·4; and 17·1, 15·6-18·7, respectively). Mortality was not associated with mean daily or cumulative doses of recombinant human growth hormone for any of the risk groups. Cause-specific mortality from diseases of the circulatory and haematological systems was increased in all risk groups. In this cohort, the largest, to our knowledge, with long-term follow-up of patients treated with recombinant human growth hormone during childhood, all-cause mortality was associated with underlying diagnosis. In patients with isolated growth hormone deficiency or idiopathic short stature, recombinant human growth hormone treatment was not associated with increased all-cause mortality. However, mortality from certain causes was increased, emphasising the need for further long-term surveillance. European Union.

Cerebral vasoreactivity, a surrogate marker of cerebrovascular disease, is not impaired in subjects with lifetime, untreated, congenital isolated GH deficiency.

Cerebrovascular disease (CeVD) is a major cause of death and disability. The role of the GH/IGF-I axis on CeVD risk is controversial. Patients with GH deficiency (GHD) in the setting of hypopituitarism often exhibit CeVD predisposing factors, like low nitric oxide generation, endothelial dysfunction, increased visceral fat mass, increased levels of LDL cholesterol, and increased intima-media thickness, a surrogate marker of atherosclerosis. However, several confounders such as the primary hypothalamic-pituitary lesion, hormonal replacement therapies, consequences of surgery and radiotherapy, may influence this relationship. Therefore, we decided to assess cerebral vasoreactivity, a surrogate marker of CeVD, in adult subjects with untreated isolated GHD (IGHD) due to the same homozygous null mutation in the GHRH receptor gene. A cross-sectional study was carried out in 25 adult IGHD subjects and 25 age- and gender-matched controls. Interview, physical examination, laboratory data, intima-media thickness measurement, and transcranial Doppler were performed. The intracranial hemodynamics (mean flow velocity, pulsatility and resistance indexes) were measured, and the response to the vasodilatory stimulus by breath-holding maneuver (breath-holding index) was calculated. IGHD and control groups were similar in Framingham risk score and intima-media thickness. Similarly, there was no difference in mean flow velocity, pulsatility, resistance, and breath-holding index. Lifetime, untreated IGHD does not cause impaired cerebral vasoreactivity.

A Genome-Wide Pharmacogenetic Study of Growth Hormone Responsiveness.

ContextIndividual patients vary in their response to growth hormone (GH). No large-scale genome-wide studies have looked for genetic predictors of GH responsiveness.ObjectiveTo identify genetic variants associated with GH responsiveness.DesignGenome-wide association study (GWAS).SettingCohorts from multiple academic centers and a clinical trial.PatientsA total of 614 individuals from 5 short stature cohorts receiving GH: 297 with idiopathic short stature, 276 with isolated GH deficiency, and 65 born small for gestational age.InterventionAssociation of more than 2 million variants was tested.Main Outcome MeasuresPrimary analysis: individual single nucleotide polymorphism (SNP) association with first-year change in height standard deviation scores. Secondary analyses: SNP associations in clinical subgroups adjusted for clinical variables; association of polygenic score calculated from 697 genome-wide significant height SNPs with GH responsiveness.ResultsNo common variant associations reached genome-wide significance in the primary analysis. The strongest suggestive signals were found near the B4GALT4 and TBCE genes. After meta-analysis including replication data, signals at several loci reached or retained genome-wide significance in secondary analyses, including variants near ST3GAL6. There was no significant association with variants previously reported to be associated with GH response nor with a polygenic predicted height score.ConclusionsWe performed the largest GWAS of GH responsiveness to date. We identified 2 loci with a suggestive effect on GH responsiveness in our primary analysis and several genome-wide significant associations in secondary analyses that require further replication. Our results are consistent with a polygenic component to GH responsiveness, likely distinct from the genetic regulators of adult height.

SUN-067 Pituitary Dysfunction in Children with Ectopic Posterior Pituitary

Background: Imaging studies aid in the detection of structural abnormalities that may be associated with pituitary dysfunction, such as ectopic posterior pituitary (EPP). The location of the ectopic lobe can vary, but it is most commonly located along the median eminence in the floor of the third ventricle. An EPP could result from complete or partial defective neural migration during embryogenesis, which could explain the different loci of EPP. Affected individuals have either severe isolated growth hormone deficiency (IGHD) or combined pituitary hormone deficiencies (CPHD); diabetes insipidus is not a feature, indicating that the EPP is functioning normally. Aim: To detect the prevalence of IGHD or CPHD in children with EPP. In addition, to evaluate the association between the location of EPP and pituitary dysfunction. Methods: A retrospective chart review of MRI reports at St. Christopher’s Hospital for Children (SCHC) from 2006-2018 that were found to have EPP. Pituitary hormone function was evaluated in the majority of the patient population. Results: Of the 26 patients with EPP, [16 males (M) and 10 females (F)], mean chronologic age was 5.98+5.18 yrs, only 20 patients had an endocrine evaluation at SCHC. Of the 20 children, 14 had CPHD and 4 had IGHD.Patients were classified into 3 groups (upper, middle & lower) according to EPP location along the pituitary stalk. Of the 21 patients with upper EPP, 17 had pituitary dysfunction (14 with CPHD, 3 with IGHD). Of the 4 children with middle EPP, only 1 had pituitary dysfunction which was IGHD. One patient had lower EPP with hyperprolactinemia. Diabetes insipidus was not identified in any of the children. Conclusion: Our study supports previous reports that CPHD and IGHD are frequent in patients with EPP. Similarly, our data further demonstrate that no cases of diabetes insipidus have been reported in children with EPP.In our study, EPP is most commonly located along the upper third of pituitary stalk at the median eminence level, with a higher prevalence of CPHD and IGHD, a finding similar to prior studies. No CPHD was reported in middle/lower but IGHD was found in the middle EPP group.

SAT-LB19 Is There a Need to Use Gadolinium Contrast for Pituitary MRI in the Evaluation of Pediatric Short Stature and Growth Hormone Deficiency?

SAT-LB19 Is There a Need to Use Gadolinium Contrast for Pituitary MRI in the Evaluation of Pediatric Short Stature and Growth Hormone Deficiency?

SAT-295 An Extremely Rare Novel Missense Variant C.912G≫A; P.M304I in SOX3 Gene Is Responsible for X-Linked GH Deficiency in a Brazilian Boy Without Mental Retardation

SOX3 (SRY-related HMG-box gene 3), located in the X chromosome, spans only one exon and is expressed in the infundibulum, diencephalon and hypothalamus. Alterations in SOX3, mainly deletions or insertions in the polyalanine tract, were associated with mental retardation, isolated GH deficiency (IGHD) or combined pituitary hormone deficiencies (CPHD). Missense variants are rare and only two were reported. Our aim was to find a molecular cause in patients with pituitary hormone deficiency and determine genotype-phenotype correlation. Twenty-eight patients (15F:13M) 24 CPHD:4 IGHD were selected for the study. Whole blood DNA was extracted using the Salting Out method. Library preparation was performed following Agilent’s SureSelectXT customized gene panel protocol containing 654 genes known to cause endocrine diseases. Illumina NextSeq 500 platform was used for sequencing at SELA. Alignment to genome reference hg19 was performed using BWA-MEM. Variants were called with FreeBayes and annotated by Annovar. Allele frequency ≤1% for exonic regions was considered in 1000 Genomes, gnomAD, ABraOM and SELA populational databases for variant filtering. Family segregation was done using Sanger sequencing. RNA and protein analysis were performed using mfold and YASARA, respectively. Protein models were made by I-Tasser. SOX3 missense variant (c.912G>A/p.M304I) was found in one male patient, without mental retardation, diagnosed with IGHD at the age of 7 years. After GH replacement, he reached final height at the age of 18 within family target height. Pituitary image showed an ectopic posterior pituitary, hypoplastic anterior pituitary and thin pituitary stalk. SOX3 (c.912G>A/p.M304I) variant in hemizygous state was absent in populational data banks. In silico prediction algorithms SIFT, PolyPhen, and Mutation Assessor were predicted as damaging. Family segregation showed normal mother and sister carriers of the variant, while father, brother and uncle (from mother’s side), all phenotypically normal, did not harbor the variant. RNA In silico analysis pointed that the variant causes mRNA structure change. Protein stability dropped from 677.46 kcal/mol in wild type to 666.69 kcal/mol in p.M304I, making it less stable. Protein Interaction analysis with DNA binding motif (PDB 2LE4) required two times less energy in mutant (376.19 kcal/mol) than wild type protein (646.77 kcal/mol), leading to a less stable interaction. We conclude that one among 28 patients presented a rare novel variant in SOX3 associated to IGHD in a patient without mental retardation and compatible with an X-linked inheritance pattern.

OR16-04 OTX2 Mutations in Congenital Hypopituitarism Patients

The transcription factor OTX2 is implicated in pituitary, ocular and craniofacial development. Mutations have been described in patients with variable congenital hypopituitarism (CH) ranging from isolated growth hormone deficiency (IGHD) to combined pituitary hormone deficiency (CPHD) with/without an ectopic posterior pituitary (EPP).We aimed (i) to establish the contribution of OTX2 mutations in the etiology of CH in a sub-cohort of patients and to study their functional consequences and (ii) establish a detailed human OTX2 expression profile in a hypothalamo-pituitary (HP) context. We screened 127 patients from national (n=103) and international centers (n=24) on the septo-optic dysplasia (SOD) spectrum with variable eye abnormalities. Eye abnormalities included micro/anophthalmia, retinal dystrophy and/or coloboma in 29 of these patients, with the rest having optic nerve hypoplasia (ONH). An EPP was reported on MRI in 35 patients. The cohort previously tested negative for mutations in HESX1, SOX2, SOX3, PROKR2 and GH1. Transactivation assays involved a dual-luciferase reporter in murine hypothalamic GT1-7 neurons transiently transfected with OTX2 constructs. In situ hybridization was performed to analyze human brain OTX2 expression during embryogenesis. Seven heterozygous OTX2 changes were identified: two chromosomal deletions spanning OTX2 in patients with micro/anophthalmia, GHD and an EPP, with one patient having cerebellar hypoplasia. Three missense substitutions resulting in truncated proteins: (i) the previously reported p.S138* and (ii) p.C170*, in two patients with retinal dystrophy, EPP and IGHD respectively, and (iii) the novel p.E79* in a patient with micro/anophthalmia, EPP and CPHD. A novel insertion-deletion resulting in a truncated protein p.S167* in a patient with microphthalmia, GHD, ONH, EPP and an enlarged abnormal pituitary, and a novel deletion resulting in a frameshift p.Val139Aspfs*39 in a patient with microcephaly, microphthalmia, ONH and an EPP were also identified. The human OTX2 variants caused a significant reduction in transactivation compared to wild type. Our gene expression data identified human OTX2 transcripts in the posterior pituitary, retina, ear, thalamus, choroid plexus, and in the hypothalamus during embryogenesis, but not in RP. To conclude, we identified OTX2 variants in 7 unrelated CH patients with eye abnormalities including 3 with retinal dystrophy and one with a cerebellar abnormality. As OTX2 is involved at multiple levels during HP development, these patients should be monitored for evolving endocrinopathies. Human OTX2 is expressed in the posterior pituitary, the retina and the ear at CS19 and 20 (between 6-7 weeks gestation), and in areas of the hindbrain at CS23, but not in RP at any stage analyzed in this study. The endocrine phenotypes in patients with OTX2 mutations are most likely of hypothalamic origin.

MON-LB014 Autosomal Dominant Growth Hormone Deficiency Due to a Novel c.178g&amp;gt;A Mutation in the GH1 Gene Is Caused by Alternative Splicing to Produce a Small GH Isoform

Introduction: Growth hormone (GH) plays a vital role in human physiology. Mutations in GH1 cause isolated growth hormone deficiency (GHD). The most frequent cause of familial growth hormone deficiency is Type II autosomal dominant GHD (isolated GHD type II) due to several heterozygous GH1 mutations. These mutations have been shown to (a) produce shorter isoforms of GH that do not bind to growth hormone receptors, (b) cause diminished secretion of GH, or (c) result in misfolded GH protein. Methods: Genomic DNA from patients with familial GHD was enriched for the coding exons using hybrid capture technology, and GH1 was sequenced using Next Generation Sequencing technology. The p.A34T mutant protein was expressed in bacteria, and binding to GHR was studied by surface plasmon resonance technology. Computational prediction of transcription indicated that alternative splicing is likely to produce a shorter GH variant with skipping of exon 3 in GH1. Mammalian cell-based studies incorporating transfection of whole GH1 gene containing exons/introns were used to study transcriptional effects. RNA was isolated from cells transfected with WT and mutant GH1 gene and analyzed by RT PCR using primers in the second and fifth exons of GH1 that could identify all possible isoforms of GH1 mRNA. Results: GHD was identified in three female siblings aged 3.25-6.33 years (Ht SDS -3.21 to -1.13, peak GH 2.9-6.6 ng/mL); their mother had previously been diagnosed with GHD at age 12.33 years (Ht SDS -3.44, GH peak < 2 ng/mL). Sequencing of GH1 identified a novel heterozygous variant (c.178G>A; p.Ala34Thr) not found in the Broad ExAc dataset representing >60,000 children without the severe childhood-onset disease. Functional studies using whole gene transfection showed that the c.178G>A mutation leads to alternate splicing resulting in increased production of the shorter 17.5kD isoform of GH due to exon 3 skipping. Results were confirmed by quantitative RT-PCR as well as GH secretion assays, which showed a lower level of GH production from cells transfected with the GH1 gene containing the c.178G>A mutation. The SPR based receptor binding assay and cell proliferation assay using bacterially expressed proteins showed that once produced, the GH protein with the A34T mutation behaves similar to WT GH protein. All these results confirm that the cause of GHD due to the c.178G>A mutation in GH1 is due to altered transcription leading to the production of the shorter 17.5 kD isoform of GH protein and not due to the amino acid change A34T that is caused by the mutation. Conclusion: The presence of a heterozygous GH1 variant (c.178G>A, p.Ala34Thr) in four individuals with GHD suggests that this is a novel cause of IGHD type II. Production of the smaller 17.5 kD GH isoform results in reduced overall GH secretion and loss of binding to GHR due to competition with the normal GH protein, explaining the dominant-negative phenotype.

SUN-LB2 Undescended Testicle and Short Stature as Manifestation of Pituitary Stalk Interruption Syndrome a Report From Saudi Arabia

BackgroundPituitary stalk interruption syndrome (PSIS) is a congenital disease with isolated growth hormone deficiency or multiple anterior pituitary hormone deficiencies. Here, the authors report a case of PSIS from Saudi Arabia.Clinical CaseA 16 year old Saudi boy presented to the endocrine clinic with short stature and undescended testis, status post bilateral orchidopexy. He was delivered by caesarean section because of breech presentation and birth asphyxia. Investigation revealed underdeveloped secondary sexual characteristics with decreased facial and pubic hair growth. The patient height was 134 cm whereas the bone age was 9 - 11 years. Pelvis examination showed a scrotum with bilateral 1 mL testes and the stretch penile length was 3 cm.The patient laboratory investigations showed hemoglobin level of 13 g/dL, serum sodium 140 mmol/L, serum potassium 4.1 mmol/L, serum chloride 102 mmol/L, calcium 9.1 mg/dL, random blood sugar 110 mg/dL and albumin 3.8 mg/dL. A pituitary hormone profile showed hypopituitarism with thyroid, and adrenal sparing. The patient free T4 was 17.3 pmol/L (9-25 pmol/L) and synacthen test revealed a morning baseline cortisol level of 6.5 µg/dL (normal = 4.3-22.4 ug/dL) with adrenocorticotrophic hormone of 9.8 pmol/L (1.1 - 13.2 pmol/L). Insulin-like growth factor 1 level 50 ng/dL (normal = 193.0 - 731.0 ug/L), follicle-stimulating hormone 0.35 µIU/mL (normal, 0.0-10.0), and leutinizing hormone 0.4 µIU/mL (normal = 1.2-7.8). The patient’s morning testosterone level showed 8 ng/dL (normal = 280-800 ng/dL) and prolactin 116 mIU/L (normal = 86 - 324 mIU/L). There were no symptom suggestive of posterior pituitary involvement like polyuria and polydipsia as urine and serum osmolality. The MRI examination showed no pituitary gland identified in the sella turcica and no clear pituitary stalk. A T1 hyperintense focus with post-contrast enhancement was identified posterior to the optic chiasma representing an ectopic posterior pituitary gland. The growth hormone and testosterone therapy were added to medical therapy of the patients and no thyroid or hydrocortisone replacement therapy was given. Conclusion: Despite the fact that this is a rare disorder, it should always be kept in the differential diagnosis of a patient presenting with short stature. Patients with this disease have an excellent opportunity to reach normal height if they present before the joining of epiphyses.