Edition 69 - 2018, July-August / Subject Review

Subject Review – Ed. 69

Second Report of ENDO2018, the 100th Annual Meeting of the ENDOCRINE SOCIETY – MARCH 17 – 20, 2018

Marco A. Rivarola y Alicia Belgorosky. Servicio de Endocrinología, Hospital de Pediatría Garrahan, Buenos Aires, Argentina. 

Information on ENDO 2018 can be obtained from www.endocrine.org/endo-2018. ENDO 2018 abstracts are accessible online at endocrine.org/2018 abstracts.

A selection of Oral presentations of Pediatric Endocrinology interest follows:

Session OR14 (Oral Session 14). Pediatric Endocrinology – Puberty, Sexual Differentiaton, Thyroid and Obesity.

Prevalence of Medical Comorbidities and Trajectory of Gender-Related Medical Interventions among Youth Aged 5-21 Presenting with Gender Dysphoria: A Community Based Study. Presentation Number: MON-181
Date of Presentation: March 19, 2018, 2018.

Reese Imhof, BA1, Haleigh James, MD2, Aradhana Sahoo, BS1, Monique Montenegro, BFA1, Alice Y. Chang, MD, MSc2, Aida Nadim Lteif, MD2, Nicole R. Imhof, MA, MSW2, Cesar Gonzalez, PhD2, Todd B. Nippoldt, MD2, Caroline Jane Davidge-Pitts, MBBCH2.
1Mayo Clinic School of Medicine, Rochester, MN, USA, 2Mayo Clinic, Rochester, MN, USA. Abstract

Authors sought to determine the prevalence of medical comorbidities and gender-related medical interventions among youth in a community-based setting. Data from the Rochester Epidemiology Project, a population-based cohort with an infrastructure that links medical records across multiple institutions to residents of Olmsted County, Minnesota, was utilized as the sampling frame for this study. They conducted a retrospective medical record review of all youth (up to and including age 21 years) who received medical care related to gender dysphoria (GD) in Olmsted County between 1976 and 2015. 34 pediatric patients had a GD-related diagnosis and underwent care related to GD. The mean age at diagnosis was 15 years (range 5-21). Of the patients assigned male at birth (AMAB), 15 identified as female, 2 identified as gender fluid, and 1 was unclear. Of the patients assigned female at birth (AFAB), 15 identified as male and 1 identified as gender fluid at baseline. From baseline to the most recent follow-up visit, 5 (14.7%) patients reported a different gender identity than initially reported. 61% of patients received feminizing hormone therapy (HT) for GD (mean 19 years; range: 16-22) and 25% received masculinizing HT for GD (mean 18 years; range 13-20). 2 patients received GnRH analogs prior to initiating HT. Of the patients that did not go on to receive HT, 26% reported a differing gender identity than was reported at baseline. 28% of patients AMAB and 12.5% of patients AFAB went on to receive surgical intervention to manage GD at an average age of 22 years (range 20-24). Depression and anxiety were diagnosed in 70.6% and 61.8%, respectively. 8.8% were diagnosed with autism spectrum disorders. A history of psychiatric hospitalization was identified in 47.1%. Suicidal ideation was reported by 64.7%, 23.5% had a documented suicide attempt and 44% had a history of non-suicidal self-injury. Substance abuse reported included marijuana (33%), tobacco (27%) and prescription opioids (9.1%).
Medical comorbidities in patients AMAB included dyslipidemia, occurring in 16.7%, with 66.7% diagnosed after starting estradiol therapy. Hypertension and polycythemia were most common in patients AFAB, occurring in 18.8% and 12.5% respectively; 66.7% of hypertension and 100% of polycythemia cases were diagnosed after initiating testosterone. Obesity was diagnosed in 25% AFAB, and 16.7% AMAB. One case of breast cancer was diagnosed in a patient AFAB.
Findings suggest that medical comorbidities are common among youth presenting with gender dysphoria. Youth with gender dysphoria often will utilize hormone therapy and surgical interventions to manage gender dysphoria. In addition, we found that all patients who ultimately underwent hormone or surgical intervention persisted in their gender identity from their baseline visit for gender dysphoria.

Characterization of a Large Cohort of Subjects with Disorders of Sex Development Admitted to a Single Pediatric Hospital

Presentation Number: MON-182
Date of Presentation: March 19, 2018, 2018

Maria Sol Touzon, Biochemistry1, Mariana Costanzo, MD2, Esperanza Beatriz Berensztein, PHD2, Pablo Cesar Ramirez, PhD2, Natalia Perez Garrido, PhD2, Roxana Marcela Marino, PhD2, Laura Galluzo, MD2, Elisa Vaiani, MD2, Marta Graciela Cristina Ciaccio, MD2, Marco A. Rivarola, MD1, Svetlana A. Yatsenko, PhD3, Gabriela Guercio, MD,PHD1, Aleksandar Rajkovic, MD, PHD3, Alicia Belgorosky, MD,PHD1.
1Hospital de Pediatria Garrahan, CONICET, Buenos Aires Capital Fed, Argentina, 2Hospital de Pediatria Garrahan, Buenos Aires Capital Fed, Argentina, 3Magee-Womens Research Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.

Abstract

Disorders of sex development (DSD) are those congenital conditions in which development of chromosomal, gonadal, or anatomical sex is atypical. The aim of this study is to characterize a cohort of (n=326) DSD patients followed at Garrahan Pediatric Hospital. The patients (P) were classified in 3 groups (G1, G2, G3) according to karyotype: G1 sex chromosome DSD n=49, G2 46,XY DSD n=83 families (F) and G3 46,XX DSD n=194 F.
In G1 clinical phenotype shows female normal external genitalia in 35%, with a significantly higher incidence of gonadal tumors, compared to the atypical external genitalia. In G2 and G3 genomic DNA and in G3, also gonadal DNA, were analyzed. Sequence by Sanger and copy number variations (CNVs) by MLPA of candidate genes were studied. In G3 whole exome sequencing (WES) and whole genome CGH+SNP microarray were included only for SRY-negative cases. In G2, the patients with disorders of gonadal development (n=40) showed deleterious gene mutations in SRY (2 siblings), NR5A1 (7 F) and WT1 (9 P). In patients with disorders of androgen synthesis (n=7), StAR was mutated in 1P, CYP17A1 in 1P, HSD3B2 in 2P and POR in 2P. In patients with disorders of androgen action (n=36), AR showed mutations in 14 F (22 family members) and SRD5A2 in 2 P.
The 46,XX DSD group encompasses patients with androgen excess (n=177): CAH due to CYP11B11F, HSD3B21P,CYP21A2161F and POR 7P; aromatase deficiency 7P.

The 46,XX-SRY negative patients were divided in 2 groups for the result analysis: nonsyndromic DSD (n=13) and syndromic DSD (n=4).Clinically significant chromosomal alterations were detected in 2/4 with syndromic DSD. A complex deletion/duplication rearrangement involving the 12p, a loss in copy number in the 9q31.2 region as well as multiple contiguous stretches of homozygosity were identified in the child of related parents (coefficient of consanguinity of 1/8). The second patient was found to carry an 11.2 Mb deletion in 1p chromosome, containing multiple genes implicated into ovarian development. WES analysis revealed 2 novel mutations in the fourth zinc finger domain of WT1 in 3 isolated DSD patients. Histological studies showed bilateral dysgenetic testes in two of them and bilateral ovotestes with gonadoblastoma and dysgerminoma in the other. It has recently been reported that the alteration in WT1 might lead to an  upregulation of testis determining genes and a reduced activation of FOXL2 promoter. In this cohort, no gene alteration was found in 40% of disorders of gonadal development of both 46,XX and 46,XY. This suggests that noncoding regions of the DNA, environmental factors and/or epigenetic pathways might represent a new challenge for understanding the etio-pathogenesis of DSD.

Copy Number Variants (CNV) in Syndromic Patients with Disorders of Sex Development

Presentation Number: MON-183
Date of Presentation: March 19, 2018, 2018

Jose Antonio Diniz Faria, MD1, Rafael Loch Batista, MD2, Nathalia Lisboa Rosa Almeida Gomes, MD3, Daniela Moraes, MD1, Mirian Yumie Nishi, BSC4, Evelin Zanardo, PHD1, Leslie Kulikowski, PHD1, Elaine Maria Frade Costa, MD,PHD5, Berenice Bilharinho Mendonca, MD6, Sorahia Domenice, PHD1.
1Universidade de Sao Paulo, Sao Paulo, Brazil, 2Hospital Das Clinicas, Sao Paulo SP, Brazil, 3Univ de Sao Paulo, Belo Horizonte, Brazil, 4HC FMUSP, Sao Paulo, Brazil, 5University of Sao Paulo, Sao Paulo, Brazil, 6Univ Sao Paulo Fac Med, Sao Paulo, Brazil.

Abstract

Introduction: Disorders of sex development (DSD) are congenital conditions in which chromosomal, gonadal or genital sex is atypical and affects 1:2500 live new born. Several genes and endocrine disruptors have been associated with DSD. Microarray techniques were used to clarify the diagnosis of DSD patients and several pathogenic copy number variations (CNVs) were identified, especially among the patients with multiples malformation. Our aim was to analyze a cohort of syndromic DSD patients for causative and potential new genes related to DSD. Methods: DNA samples for ten Brazilian syndromic DSD patients (four 46,XX DSD and six 46,XY DSD patients) with multiple malformations and no molecular diagnose were studied. Illumina beadarray 850K were performed to identify the presence of CNVs. No filter for CNV length was used, and those encompassing more than 10 beads consecutively were analyzed. Results: Seventy-eight CNVs (46 deletions and 32 duplications) were found plus 21 Loss of Hetorezigosity (LOH). CNVs length ranged from 5Kb to 11.5Mb. Four pathogenic CNVs in three different patients were identified. Seventeen variants of unknown significance (VUS) were also identified and the remaining were called benign. Patient 1:Born with atypical genitalia (micropenis, perineal hypospadias and bilateral cryptorchidism) associated with anorectal anomaly, facial dysmorphism and development delay. 46,XY,del(10q26) karyotype was present. A 11.5Mb deletion located on chromosome 10q25.3-q26.2 was identified, and FGFR2 was one of the deleted genes. FGFR2 has been associated with male sex differentiation in mice and humans, and previous CNV encompassing this region was associated with multiple malformative defects and atypical genitalia. Patient 2: Male born without atypical genitalia performed a microarray analysis due to multiple dysmorfism associated with epilepsy and autism. 46,XX karyotype with Yp SRY+ was identified. A 1.7Mb deletion was also identified at 3q29 region. Partial Y translocation containing SRY is a well-known cause of 46,XX testicular DSD. In this patient, the concomitance of 3q29 deletion cause probably the multiple malformative defects in a 46,XX testicular DSD patient. Patient 3: Born with penile agenesis, topic testis and anorectal anomaly. Dysmorphic limbs and facial were also present. She underwent a genital feminization surgery, bilateral gonadectomy and reared as female. Development delay and difficult to control epilepsy begun after her first year of life. She presented a 46,XY karyotype. Pathogenic 277Kb deletion was identified on chromosome 20q13.13 encompassing the KCNB1 gene, which is associated with infantile epileptic syndrome and development delay. Conclusion: The use of SNP array allowed the identification of submicroscopic deletions that potentially contribute to the disease cause in 20% of syndromic DSD patients.

DEAH-box Helicase 37 Defects are a Novel Cause of 46,XY Gonadal Dysgenesis and Embryonic Regression Testicular Syndrome (ERTS).

Presentation Number: MON-184
Date of Presentation: March 19, 2018, 2018

Natahlia Lisboa Rosa Almeida Gomes, MD1, Thatiana Evilen Silva, MSc2, Antonio Marcondes Lerario, MD3, Rafael Loch Batista, MD4, Jose Antonio Faria Junior, MD5, Daniela Rodrigues Moraes, MD5, Mirian Yumie Nishi, BSC6, Elaine Maria Frade Costa, MD,PHD7, Sorahia Domenice, MD, PhD5, Berenice Bilharinho Mendonca, MD8.
1Hospital das Clínicas – Univ de Sao Paulo, Sao Paulo, Brazil, 2Univ of Sao Paulo, Sao Paulo, Brazil, 3University of Michigan, Ann Arbor, MI, USA, 4Hospital Das Clinicas, Sao Paulo, Brazil, 5Univ de Sao Paulo, Sao Paulo, Brazil, 6HC FMUSP, Sao Paulo, Brazil, 7University of Sao Paulo, Sao Paulo, Brazil, 8Univ Sao Paulo Fac Med, Sao Paulo, Brazil.

Abstract

Background: A novel candidate gene for 46,XY disorders of sex development (DSD) due to gonadal dysgenesis (GD) has emerged after the identification of the predicted deleterious variant p.R308Q in DHX37 by whole-exome sequencing in 6 patients with micropenis and ETRS from 4 unrelated families of our cohort. The DHX37 encodes a DEAD box protein, a putative RNA helicase, which expression´s pattern in male germ cells in different stages of maturation suggests it should have a role on gonadal development.
Objective: To investigate the allelic variants identified in DHX37 in a large cohort of 46,XY DSD patients by target massively parallel sequencing (TMPS).
Patients and methods: We studied 75 sporadic and 2 familial cases from the same non-consanguineous family. Twenty six patients had complete gonadal dysgenesis (CGD), 14 patients had partial gonadal dysgenesis (PGD) and 37 patients were classified as DSD of unknown etiology (UDSD). An amplicon-based capture panel of 63 genes related to DSD, including DHX37, for targeted sequencing was designed. Sequencing was performed in the Illumina MiSEQ platform. Paired-end reads were aligned to the hg19 assembly of the human genome with BWA-MEM. Variants were called and annotated, with Platypus and ANNOVAR, respectively.
Results: TMPS identified 6 different heterozygous missense variants in DHX37 in 9 patients, including 5 patients with PGD (3 of them had ERTS), 3 UDSD patients and one CGD patient. At least 8 prediction site tools classified them as deleterious. Four novel variants (p.T304M; p.R674W; p.A492P; p.S595F) and the previously reported p.R308Q, identified in one CGD patient of this cohort, are localized in highly conserved gene regions and are absent in population databases; the p.L426V is found in a frequency of 0,0002. The p.S595F was identified in the familial cases and the p.R674W was found in two patients with ERTS and one PGD female patient, who also harbored the novel candidate variant p.P368R in GATA4. Another possible digenic variant was observed in one UDSD patient, who had a novel likely pathogenic variant in NR5A1 (p.G26V)All the segregated DHX37variants disclosed a sex-limited dominant inheritance.
Conclusion: The identification of several novel and a previous known deleterious variants in DHX37, as monogenic or as digenic inheritance, in 7 sporadic and in 2 familial cases of 46,XY DSD patients, reinforces DHX37 as a novel and strong candidate gene for the spectrum of GD phenotypes.

The Assessment of Parent-Reported Outcomes in Conditions Affecting Sex Development in the Routine Clinic Setting

Presentation Number: MON-185
Date of Presentation: March 19, 2018, 2018

Zoe Macqueen, BSc (Hons)1, Melissa Gardner, MA2, David E. Sandberg, PhD2, Andreas Kyriakou, MD1, Avril Mason, MBCHB1, M Guftar Shaikh, MB ChB MD1, Jarod Sze Choong Wong, MD1, S Faisal Ahmed, MBChB,MD,FRCPCH1.
1Developmental Endocrinology Research Group, Royal Hospital for Children, University of Glasgow, Glasgow, United Kingdom, 2Child Health & Evaluation Research Center, University of Michigan, Ann Arbor, MI, USA.

Abstract

BACKGROUND: There are substantial gaps in our understanding of the psychosocial impact of chronic conditions affecting sex development (DSD) on parents and affected individuals. AIMS: To explore whether patient-reported outcomes (PRO), assessed by standardised questionnaires, could be integrated within routine paediatric endocrine clinics. METHODS: A parent Self-Report questionnaire for caregivers of children Proxy-Report questionnaire assessing the child’s adaptation through generic and validated DSD-specific PROs was also developed. Each subscale was scored and presented as a standard deviation score (SDS) relative to DSD or community samples. Parents of 86 children who attended the endocrine clinics were approached and questionnaires were returned in 72 (84%). Questionnaires were completed by parents of 32 children with conditions affecting sex development (28 mothers, 6 fathers), 29 children (25 mothers, 5 fathers) with endocrine conditions and 11 (9 mothers, 4 fathers) with bone conditions. RESULTS: Both questionnaires were found acceptable for use in the clinic setting and took less than 10 minutes to complete. Although Proxy-Report scales scores generally fell in the positive range, the median (range) SDS score on the Self-Report subscale Future Concerns was -0.07 (-2.14, 1.73) for mothers of children with conditions affecting sex development. This was significantly lower compared to mothers of children with endocrine conditions +1.34 (-2.00, +1.73) and bone conditions +0.90 (+0.11, +1.73); (p<0.005). The group differences on Future Concerns were also seen for fathers of children with conditions affecting sex development -3.04 (-4.21, -0.30) compared to -0.37 (-1.30, +1.17) for endocrine conditions (p<0.005) and +0.48 (-2.13, +1.00) for children with bone conditions (p<0.05). Paternal Self-Report subscale scores (Healthcare Communication, Disclosure, and Future Concerns) for children with conditions affecting sex development were lower than DSD reference data (p<0.05), whereas scores for Medications and Clinic Experience were higher than the DSD reference data (p<0.005). Mothers of children with conditions affecting sex development had lower parent-focused Stigma subscale scores compared to the DSD reference data (p<0.05). CONCLUSIONS: Assessment of PROs in the routine endocrine clinic setting is feasible and has identified that parents of children with conditions affecting sex development report greater levels of stress, particularly relating to future concerns, compared to parents of children with other endocrine and bone conditions. These questionnaires can be used as a routine health care evaluation and their use may allow greater targeting of support and development of clinical benchmarks.

Growth Hormone Therapy Improves Final Height in Individuals with 45,X/46,X,+Y Variants Disorders of Sex Development (DSD)

Presentation Number: MON-186
Date of Presentation: March 19, 2018, 2018

Jose Antonio Diniz Faria, MD1, Rafael Loch Batista, MD2, NATHALIA LISBOA ROSA ALMEIDA GOMES, MD3, DANIELA RODRIGUES MORAES, MD4, MIRIAM NISHI, PHD4, FLAVIA S CUNHA, MD4, Alexander Augusto Lima Jorge, MD,PHD5, Elaine Maria Frade Costa, MD,PHD5, Berenice Bilharinho Mendonca, MD6, SORAHIA DOMENICE, PHD4.
1Universidade de Sao Paulo, Salvador, Brazil, 2Hospital Das Clinicas, Sao Paulo SP, Brazil, 3Univ de Sao Paulo, Belo Horizonte, Brazil, 4Universidade de Sao Paulo, SAO PAULO, Brazil, 5University of Sao Paulo, Sao Paulo, Brazil, 6Univ Sao Paulo Fac Med, Sao Paulo, Brazil.

Abstract

Introduction: Disorders of sex development (DSD) affects 1:2500 individuals and comprehend a wide range of conditions presenting atypical chromosomal, gonadal or anatomical sex. Chromosomal 45,X/46,XY DSD may present variable phenotypes. The external genitalia can range from normal female to wide spectrum of atypical genitalia and Mullerian ducts are often present. Turner syndrome stigma can be present and short stature is the main clinical sign identified in 45,X/46,XY DSD patients. rhGH has been proposed to treat short stature in these patients similarly to Turner syndrome, even though they have not GH deficiency. Literature has not yet reached a consensus of 45,X/46,XY DSD rhGH therapy benefits. Objective: to evaluate the final height (FH) of 45,X/46,XY DSD patients comparing the FH among rhGH treated and non-treated patients. Patients and Methods: Patients with chromosomal DSD that reached final height were invited to participate. Retrospective analysis of medical records were performed. Data regarding final height, mean parental height, rhGH therapy, duration and dose of rhGH therapy, bone age at the beginning of the treatment. Twenty-five patients were included (12 males and 13 females). Patients karyotype varied from 45,X/46,XY in 17 patients (68%), 45,X/46,X,+Y variants in 7 patients (28%) and 45,X/46,XY/47,XXY in 1 patient (4%). Target height (TH) was established in 72% of patients and did not differ between the groups. Shapiro-Wilk test was used to determine normality. Parametric data were analyzed using Student T test and non-parametric with Mann-Whitney test. Continuous variables were described as mean and standard deviation. Values of p< 0.05 were considered statistically significant. Results: Ten patients (6 males, 4 females) received 0.05mg/Kg/day of rhGH for 58.2 months (51.2 in females vs 62.8 months in males) and 15 patients (6 males, 9 females) did not use rhGH. Mean FH was 150.5±6.4cm(-3.5SD) vs 162.1±6.6cm(-1.9SD) in males and 148.8±6.2cm(-2.2SD) vs 153.4±3.7cm(-1,5SD) in females of the rhGH untreated group and rhGH treated group, respectively. Mean FH was significantly higher in the male rhGH treated group than in the male untreated group (p=0,011), but not for female group (p=0,20). A significant difference in mean FH was also observed when rhGH treated patients (157.2 ±6.9cm) vs untreated patients (148.5±6.4cm) were compared without stratifying by sex (p=0.001). The FH/TH were 0.93 and 0.95 for males and females rhGH treated and 0.89 and 0.94 for males and females untreated, respectively. Conclusion: The treatment with pharmacological doses of rhGH of DSD patients with sex chromosome abnormalities 45,X/46,XY or 45,X/46,X,+Y variants showed a significant improvement of their final adult height.

Session OR33. Disorders of the Female Reproductive Axis – PCOS, POI, and Metabolism

OR33-2Unbiased Genome-wide Analyses Reveal Insulin Receptor Recruitment to Novel Genomic Sites in Pancreatic Islets

Presentation Number: OR33-2
Date of Presentation: June 17th, 2013

Shweta Bhatt*1, Rachael Martinez2, Tze Howe Charn3, Michael Molla2 and Rohit N Kulkarni4
1Joslin Diabetes Center and Harvard Medical School, Boston, MA, 2Joslin Diabetes Center, Boston, MA, 3Stanford University, San Francisco, CA, 4Joslin Diabetes Center and Harvard Medical School, Boston, MA

Abstract

Growth hormone receptors, like the Insulin Receptor (IR), are expressed ubiquitously and mediate critical metabolic actions of insulin in target tissues to regulate glucose homeostasis. Their precise role in the pathogenesis of metabolic disorders such as type 2 diabetes continues to be unraveled by the identification of novel downstream targets. We report, for the first time, the nuclear presence of IR protein in pancreatic beta cells and hepatocytes, two target tissues important for the regulation of whole body glucose homeostasis. Further investigation in pancreatic beta cells revealed a ligand (glucose and/or insulin, IGF1) and time dependent nuclear translocation of IR protein by live-cell imaging, immuno-staining and western blot analyses (n=3). Further, bioinformatics analyses revealed a consensus sequence (SRKRRS) in IR, conserved across species, and critical for its nuclear translocation, as confirmed by site-directed mutagenesis, nuclear-cytoplasmic fractionation and western blot analyses (n=3). Interestingly, this phenomenon was consistent in mouse, human islets and isolated beta cells and mutations associated with defects in insulin processing in humans. To explore the underlying molecular mechanism, we subjected mouse pancreatic islets to ex-vivo treatment with ligands (glucose and/or insulin, IGF1) followed by (a) genome-wide chromatin immuno-precipitation sequencing (ChIPseq) analysis for IR protein to assess genomic recruitment or (b) microarray gene expression analysis to study transcript regulation. Indeed, we observed IR recruitment to 9663 genomic sites, enriched in distal intergenic and intronic regions (similar to classic nuclear receptors), and associated with 6778 unique genes. Interestingly, a significant number of these genomic targets, several with established roles in glucose homeostasis (Mafa, Igf1r, Skp2, Insig2, Foxc1, Mapk1, Wnt5a, p21 etc.), were regulated by ligand in microarray and Q-PCR analyses, suggesting functional relevance (n=3; p<0.001). Consistently, this regulation was blocked in mouse islets or beta cells obtained from beta-cell specific IR knockout (bIRKO) animals and human islets subjected to shRNA mediated IR knockdown, suggesting an essential role of IR in this regulation. In summary, our unbiased approach identifies new primary targets of IR worthy of further investigation, to identify novel pathways and understand disease mechanism(s) for therapeutic intervention.

Session OR02 – Recent Progress in Adrenal Tumors

OR02-1 – Kisspeptin and Kisspeptin Receptor May Be Involved in the Regulation of Adrenocortical Development and Steroid Hormone Secretion.

Annabel Sophie Berthon, PhD1, Nikolaos Settas, PhD1, Andreas Giannakou, MD1, Angela Delaney, MD2, Fabio Rueda Faucz, PhD3, Constantine A. Stratakis, MD, PhD41NIH, Bethesda, MD, USA, 2National Institutes of Health, Bethesda, MD, USA, 3NIH/NICHD, Bethesda, MD, USA, 4NICHD/NIH, Rockville, MD, USA.

Abstract
Knockout mice for Kisspeptin receptor, Kiss1r, (KRKO) and its ligand Kisspeptin, Kiss1, (KissKO) replicate the phenotype of isolated hypogonadotropic hypogonadism (IHH) that was described in association with these genes in humans. Recently, it has been shown that Kisspeptin may be involved in human fetal adrenal development and function. To better understand Kisspeptin’s role in the adrenal cortex, we studied adrenal function and morphology in both male and female KRKO and KissKO mice that do not go through normal puberty. Two fetal markers, 20αHSD and Cyp17, were expressed in eosinophilic cells, which are accumulated at the border between the cortex and the medulla. These cells may be derived from the fetal zone that should disappear at puberty in male and during the first pregnancy in female mice. Interestingly, KRKO and KissKO females (but not males) showed corticosterone and aldosterone hypersecretion. Although hypercorticosteronism corrected overtime, hyperaldosteronism persisted at age 14 months and correlated with overexpression of the transcription factor Star. To determine if KISS1 and KISS1R genes are involved in the development of primary aldosteronism (PA) and hypercortisolism (Cushing syndrome-CS) in humans, we sequenced these 2 genes in a cohort of 65 patients with PA and/or CS. In the KISS1 gene, we identified two polymorphisms (c.-89G>A and c.417_417delA) with a higher frequency in our cohort compared to the 1000GP dataset (14% vs 8% and 33% vs 22%, respectively). Interestingly, we found a mutation (p.H90D, rs201073751) previously reported for causing central precocious puberty (CPP) in a patient with CS without CPP. The analysis of this patient’s adrenal tumor did not reveal any somatic mutations. Moreover, we discovered three rare variants in KISS1R gene, two missense and one synonymous, in three different patients with PA: rs141767649 (p.C95W), rs73507527 (p.A189T) and rs115335009 (p.R229R). The two missense variants have been previously associated with IHH and Kallmann syndrome, respectively. Our findings suggest that KISS1 and KISS1R may play a role in adrenal function in mice and possibly adrenocortical steroid hormone secretion abnormalities in humans, beyond the recently described role in fetal adrenocortical development.

SUN-609. Data Mining And Computational Analysis Of Human Growth Hormone Gene (gh1) Sequence In Normal Population To Identify Potential Variants With Disease Causing Effects.

Amit V. Pandey, PhD, PD.
University Children’s Hospital Bern, Bern, Switzerland.

Abstract

BACKGROUND: Mutations in GH1 gene cause isolated growth hormone deficiency (IGHD). Several disease-causing mutations from patients with IGHD have been reported1, 2. These mutations have been shown to: (a) produce shorter isoforms of GH that does not bind to growth hormone receptor, (b) cause diminished secretion of GH or (c) result in misfolded or truncated GH protein. A large amount of genomics data from sequencing studies from non-clinical population is now available which shows several hundred genetic variations in GH1 gene. Role of common polymorphic variants in GH1 gene in relation to effects of GH protein has not been systematically studied. AIM: Searching the genomics data to find and analyse the effects of potentially disease-causing variants in GH1 gene. METHODS: We used hidden Markov Model methods to generate position specific scoring matrices for analysing the sequence conservation of GH amino acids across species using both the structural and the genomics data. A potential list of structurally and functionally important residues was compiled for further analysis. Computational molecular dynamics using AMBER and docking to GH receptor using Autodock-VINA was performed to study the effects of potentially disease-causing variants after in-silico mutagenesis.
RESULTS: Several potentially disease-causing variants were found in the GH1 gene from sequencing data deposited from non-clinical samples. Three different categories of changes in amino acid sequence of GH were observed. Mutations at interface of GH-GHR interactions were predicted to affect binding and affinity of GH towards GHR, while some mutations were found to cause structural instabilities in GH affecting proper folding. Certain other changes at amino terminus of GH protein sequences were predicted to change localization and secretion properties. An overview of most important variants with potential to cause IGHD were presented. CONCLUSIONS: Identification of potentially negative effects from some variations in GH1 gene from non-clinical populations can be utilized to study links to growth variations and distribution of certain common variants in GH1 gene. Identification of potentially disease-causing variants in GH1 will help in further functional characterization of these variants when these are later found in patients and linked to growth hormone deficiency.


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