The Effect of Gene Editing by CRISPR-Cas9 of miR-21 and the Indirect Target MMP9 in Metastatic Prostate Cancer

Prostate cancer (PCa) has a high prevalence and represents an important health problem, with an increased risk of metastasis. With the advance of CRISPR-Cas9 genome editing, new possibilities have been created for investigating PCa. The technique is effective in knockout oncogenes, reducing tumor resistance. MMP9 and miR-21 target genes are associated with PCa progression; therefore, we evaluated the MMP-9 and miR-21 targets in PCa using the CRISPR-Cas9 system. Single guide RNAs (sgRNAs) of MMP9 and miR-21 sequences were inserted into a PX-330 plasmid, and transfected in DU145 and PC-3 PCa cell lines. MMP9 and RECK expression was assessed by qPCR, WB, and IF. The miR-21 targets, integrins, BAX and mTOR, were evaluated by qPCR. Flow cytometry was performed with Annexin5, 7-AAD and Ki67 markers. Invasion assays were performed with Matrigel. The miR-21 CRISPR-Cas9-edited cells upregulated RECK, MARCKS, BTG2, and PDCD4. CDH1, ITGB3 and ITGB1 were increased in MMP9 and miR-21 CRISPR-Cas9-edited cells. Increased BAX and decreased mTOR were observed in MMP9 and miR-21 CRISPR-Cas9-edited cells. Reduced cell proliferation, increased apoptosis and low invasion in MMP9 and miR-21 edited cells was observed, compared to Scramble. CRISPR-Cas9-edited cells of miR-21 and MMP9 attenuate cell proliferation, invasion and stimulate apoptosis, impeding PCa evolution.

Survivin: A Potential Marker of Resistance to Somatostatin Receptor Ligands

CONTEXT

Invasive and somatostatin receptor ligand (SRL)-resistant pituitary tumors represent a challenge in the clinical practice of endocrinologists. Efforts have been made to elucidate reliable makers for both. Survivin and eukaryotic translation initiation factor-binding protein 1 (4EBP1) are upregulated in several cancers and involved in apoptosis and cell proliferation.

OBJECTIVE

We explored the role of these markers in somatotropinomas.

METHODS

Immunostains for survivin and 4EBP1, and also for somatostatin receptor type 2 (SSTR2), Ki-67, and cytokeratin 18, were analyzed in tissue microarrays containing 52 somatotropinoma samples. Tumor invasiveness was evaluated in all samples while drug resistance was evaluated in 34 patients who received SRL treatment. All these parameters were correlated with first-generation SRL (fg-SRL) responsiveness and tumor invasiveness.

RESULTS

Low survivin expression (P = 0.04), hyperintense signal on T2 weighted image (T2WI) (P = 0.01), younger age (P = 0.01), sparsely granular adenomas (SGA) (P = 0.04), high postoperative growth hormone (GH) and insulin-like growth factor-1 (IGF-1) levels (P = 0.049 and P < 0.001, respectively), and large postoperative tumor size (P = 0.02) were associated with resistance to fg-SRL. Low survivin and SSTR2 expression and high 4EBP1 expression were associated with SGA (P = 0.04, P = 0.01, and P = 0.001, respectively). Younger age (P = 0.03), large tumor pre- and postoperative (P = 0.04 and P = 0.006, respectively), low SSTR2 expression (P = 0.03), and high baseline GH and IGF-1 (P = 0.01 and P = 0.02, respectively) were associated with tumor invasiveness. However, survivin, 4EBP1, Ki-67, and granulation patterns were not associated with tumor invasion.

CONCLUSION

This study suggests that low survivin expression is predictive of resistance to fg-SRL in somatotropinomas, but not of tumor invasiveness.

Impaired Bone Microarchitecture in Premenopausal Women With Acromegaly: The Possible Role of Wnt Signaling

CONTEXT

Acromegaly can impair bone integrity, increasing the risk of vertebral fractures (VFs).

OBJECTIVE

To evaluate the impact of isolated GH/IGF-I hypersecretion on bone turnover markers, Wnt inhibitors, bone mineral density (BMD), microarchitecture, bone strength and vertebral fractures in female patients with acromegaly (Acro), compared with healthy control group (HC).

DESIGN, SETTING, AND PATIENTS

Cross-sectional study including 83 premenopausal women without any pituitary deficiency:18 acromegaly in remission (AcroR), 12 in group with active acromegaly (AcroA), and 53 HC. Serum procollagen type 1 N-terminal propeptide, β-carboxy-terminal crosslinked telopeptide of type 1 collagen, osteocalcin, sclerostin, and DKK1 were measured in blood samples. dual-energy X-ray absorptiometry, high-resolution peripheral quantitative computed tomography (HR-pQCT) and vertebral fractures evaluation were also assessed simultaneously.

MAIN OUTCOME AND RESULTS

AcroA showed significantly lower sclerostin and higher DKK1 compared with HC. On HR-pQCT of tibia and radius, Acro showed impairment of trabecular (area and trabecular number), increased cortical porosity, and increased cortical area and cortical thickness compared with HC. The only significant correlation found with HR-pQCT parameters was a positive correlation between cortical porosity and serum DKK1 (R = 0.45, P = 0.044). Mild VFs were present in approximately 30% of patients.

CONCLUSIONS

Eugonadal women with acromegaly without any pituitary deficiency showed increased cortical BMD, impairment of trabecular bone microstructure, and increased VF. Sclerostin was not correlated with any HR-pQCT parameters; however, DKK1 was correlated with cortical porosity in tibia (P = 0.027). Additional studies are needed to clarify the role of Wnt inhibitors on bone microarchitecture impairment in acromegaly.

Genetics, clinical features and outcomes of non-syndromic pituitary gigantism: experience of a single center from Sao Paulo, Brazil

PURPOSE

Non-syndromic pituitary gigantism (PG) is a very rare disease. Aryl hydrocarbon receptor-interacting protein (AIP) and G protein-coupled receptor 101 (GPR101) genetic abnormalities represent important etiologic causes of PG and may account for up to 40% of these cases. Here, we aimed to characterize the clinical and molecular findings and long-term outcomes in 18 patients (15 males, three females) with PG followed at a single tertiary center in Sao Paulo, Brazil.

METHODS

Genetic testing for AIP and GPR101 were performed by DNA sequencing, droplet digital PCR and array comparative genomic hybridization (aCGH).

RESULTS

Pathogenic variants in the AIP gene were detected in 25% of patients, including a novel variant in splicing regulatory sequences which was present in a sporadic male case. X-LAG due to GPR101 microduplication was diagnosed in two female patients (12.5%). Of interest, these patients had symptoms onset by age 5 and 9 years old and diagnosis at 5 and 15 years, respectively. X-LAG, but not AIP, patients had a significantly lower age of symptoms onset and diagnosis and a higher height Z-score when compared to non-X-LAG. No other differences in clinical features and/or treatment outcomes were observed among PG based on their genetic background.

CONCLUSION

We characterize the clinical and molecular findings and long-term outcome of the largest single-center PG cohort described so far.

ESR1 polymorphism (rs2234693) influences femoral bone mass in patients with Turner syndrome

Most patients with Turner syndrome (TS) need hormone replacement therapy because of hypergonadotropic hypogonadism; individual outcomes, however, are highly variable. Our objective was to assess the influence of five estrogen receptor 1 gene (ESR1) polymorphisms (rs543650, rs1038304, rs2046210, rs2234693 and rs9340799) on adult height, breast development, uterine volume and bone mineral density (BMD). We studied 91 TS patients from a tertiary hospital using adult estrogen dose. In our group, ESR1 rs2234693 was associated with femoral neck and total hip BMD, and it accounted for around 10% of BMD variability in both sites (P < 0.01). Patients homozygous for C allele in this polymorphism had significantly lower femoral neck BMD (0.699 ± 0.065 g/cm2 vs 0.822 ± 0.113 g/cm2, P = 0.008) and total hip BMD (0.777 ± 0.118 g/cm2 vs 0.903 ± 0.098 g/cm2, P = 0.009) than patients homozygous for T allele. The other four ESR1 polymorphisms were not able to predict any of the above estrogen therapy outcomes in an isolated manner. Patients homozygous for the haplotype GCG formed by polymorphisms rs543650, rs2234693 and rs9340799 had an even more significantly lower femoral neck BMD (0.666 ± 0.049 vs 0.820 ± 0.105 g/cm2, P = 0.0047) and total hip BMD (0.752 ± 0.093 vs 0.908 ± 0.097 g/cm2, P = 0.0029) than patients homozygous for haplotypes with a T allele in rs2234693. In conclusion, homozygosity for C allele in ESR1 rs2234693 and/or for GCG haplotype appears to be associated with lower femoral neck and total hip BMD. We believe that the identification of polymorphisms related to estrogen outcomes may contribute to individualization of treatment in TS.

New Insights Into Pheochromocytoma Surveillance of Young Patients With VHL Missense Mutations

Context

Von Hippel-Lindau (VHL) disease is an autosomal dominant syndrome caused by germline mutations in the VHL gene. Guidelines recommend pheochromocytoma (PHEO) biochemical screening should start at age 5 years.

Objective

Genotype–phenotype correlations in VHL, focusing on PHEO penetrance in children, were studied.

Design

We retrospectively evaluated 31 individuals (median age at diagnosis was 26 years) with diagnosed VHL disease.

Results

PHEO was diagnosed in six children with VHL. A large PHEO (5 cm) was detected in a 4-year-old boy with p.Gly114Ser mutation. PHEO penetrance was 55% starting at age 4 years. VHL missense mutations were identified in 11 of 22 families (50%), frameshift mutations in four (18.2%), stop codon in three (13.6%), splicing site in two (9.1%), and large gene deletion in two (9.1%). The codon 167 (n = 10) was a hotspot for VHL mutations and was significantly associated with PHEO (90% vs. 38%; P = 0.007). PHEOs and pancreatic neuroendocrine tumors (PNETs) were strongly associated with VHL missense mutations compared with other mutations (89.5% vs. 0% and 73.7% vs. 16.7%; P = 0.0001 and 0.002, respectively). In contrast, pancreatic cysts (91.7% vs. 26.3%; P = 0.0001), renal cysts (66.7% vs. 26.3%; P = 0.027), and central nervous system hemangioblastomas (91.7% vs. 47.3%; P = 0.012) were more frequent in VHL with nonmissense mutations.

Conclusion

VHL missense mutations were highly associated with PHEO and PNETs. Our data support that in children with VHL harboring missense mutations, biochemical screening for PHEO should be initiated at diagnosis.

Association between KISS1 rs5780218 promoter polymorphism and onset of growth hormone secreting pituitary adenoma

OBJECTIVES

This study analyzed the KISS1 c.-145delA (rs5780218) promoter polymorphism in a cohort of patients with growth hormone secreting pituitary adenoma (somatotropinoma) and controls, to investigate its role in the incidence of acromegaly and to assess patient/tumor characteristics. Material and methods rs5780218 allelic and genotypic distributions were compared between 49 somatotropinoma patients and 167 healthy controls. rs5780218 was also assessed in relation to patient characteristics and tumor aggressiveness, as characterized by tumor invasion and resistance to conventional therapy. The relationship between KISS1 mRNA expression and the rs5780218 genotype was also assessed in available pituitary tumor samples.

RESULTS

The homozygous -/- variant genotype was associated with high rates of somatotropinoma (P<0.01), but not with tumor invasiveness, patient characteristics or hormonal remission. KISS1 mRNA expression was much lower in somatotropinomas carrying the deleted allele than in homozygous wild type AA.

CONCLUSIONS

In this pilot study, the rs5780218 promoter polymorphism was evaluated in pituitary adenoma, and showed a possible association with the incidence of somatotropinoma but not with tumor progression.

Differential gene expression of sirtuins between somatotropinomas and nonfunctioning pituitary adenomas

Sirtuins 1-7 (SIRT) are a highly conserved family of histone deacetylases involved in the regulation of longevity that have a considerable impact in transcription, DNA repair regulation, telomeric stability, cell senescence and apoptosis. In the present study, SIRT1-7 mRNA levels were evaluated in 37 somatotropinomas and 31 nonfunctioning pituitary adenomas (NFPAs) using qPCR and relation to tumor size, invasiveness and Ki-67 proliferative index was made. Overexpression of SIRT1 was observed in 86.5% of somatotropinomas versus 41.9% of NFPAs (P < 0.01). SIRT3 was more underexpressed in NFPAs than somatotropinomas (77.4 and 40.5%, respectively, P < 0.01) as well as SIRT4 and SIRT7. Despite the lack of association between sirtuins and invasiveness or Ki-67 index, SIRT1 and SIRT3 expressions were related to tumor size. Mean of the largest diameter was smaller in adenomas with SIRT1 overexpression than with normal expression (P < 0.01) and SIRT3 underexpression was associated with larger tumors (P < 0.01). In conclusion, a pronounced difference in sirtuins expression was identified between pituitary adenomas, suggesting that these genes are potential markers of pituitary adenomas and could be employed in the characterization of somatotropinomas and NFPAs. The role of sirtuins in pathogenesis of pituitary tumors merits further investigation and possibly will provide new molecular insight about their progression.

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.

Cabergoline and prolactinomas: lack of association between DRD2 polymorphisms and response to treatment

BACKGROUND

About 80% of prolactinomas respond to dopamine agonists (DA) with hormonal normalization and tumor shrinkage. Mechanisms of DA resistance include reduction of dopamine receptor subtype 2 (DRD2) expression, short and long isoform ratio and post-receptor mechanisms. It was suggested that polymorphisms in the gene encoding dopamine receptor subtype 2 gene (DRD2) could be associated with variable effectiveness of cabergoline (CAB).

OBJECTIVE

To assess the influence of DRD2 polymorphisms in responsiveness of CAB treatment in patients with prolactinoma.

STUDY DESIGN AND PATIENTS

Cross-sectional retrospective case-control study analyzing the frequency of five DRD2 polymorphisms in 148 patients with prolactinoma and 349 healthy subjects. The association of genetic variants and clinical characteristics with CAB responsiveness was performed in 118 patients (mean age at diagnosis 29 years; range 11-61 years) with hormonal evaluation. Patients with prolactin (PRL) normalization were considered as responders.

RESULTS

No association in genotypes and allele proportions was found comparing patients and controls. On pharmacogenetic study, 118 patients on CAB were included and 20% were non-responders. No association was found between clinical characteristics (gender, age, PRL level and tumor size at diagnosis) and polymorphisms of DRD2 with CAB responsiveness. Otherwise, there was association between polymorphisms rs1076560 (allele A) and rs1800497 (allele T) and the presence of macroadenomas.

CONCLUSION

No correlation was found between DRD2 polymorphisms and CAB responsiveness in patients with prolactinoma. More data are necessary in order to assess the influence of DRD2 genotyping on DA treatment response.

SOCS2 polymorphisms are not associated with clinical and biochemical phenotypes in acromegalic patients

PURPOSE

Suppressor of cytokine signaling 2 (SOCS2) is a STAT5b-regulated gene and one of its functions is to influence growth and development through negative regulatory effects on GH/IGF-1 pathway. So, we evaluate the potential influence of SOCS2 single nucleotide polymorphisms (SNPs) on clinical and laboratorial characteristics of a large cohort of Brazilian patients with acromegaly.

METHODS

Four SOCS2 SNPs (rs3782415, rs3816997, rs3825199 and rs11107116) were selected and genotyped by real-time PCR using specific Taqman probe assays. A total of 186 patients (116 women, age range 26-88 years) were evaluated.

RESULTS

No association of SOCS2 genotypes was observed with none of the following clinical and laboratorial characteristics: age, sex, body mass index, comorbidities, basal GH, oral glucose tolerance test GH nadir, IGF-I, ULNR-IGF-I.

CONCLUSION

Despite of the key role of SOCS2 in the regulation of GH receptor signaling, we did not find any significant association between SOCS2 polymorphisms and acromegaly.

Influence of growth hormone receptor (GHR) exon 3 and -202A/C IGFBP-3 genetic polymorphisms on clinical and biochemical features and therapeutic outcome of patients with acromegaly

BACKGROUND

The association of GHR-exon 3 and -202 A/C IGFBP3 polymorphisms with clinical presentation, biochemical measurements and response to therapies in acromegaly have been suggested.

OBJECTIVE

To evaluate the presence of these polymorphisms in acromegaly and their influence on clinical and laboratorial characteristics of patients at diagnosis and after treatment in a large cohort of acromegalic patients.

PATIENTS AND METHODS

This is a cross-sectional study developed in a single tertiary reference center. Clinical data were obtained from the medical records of 186 acromegalic patients (116 women, age range 21-88 years). GH and IGF1 levels and GHR-exon 3 and -202 A/C IGFBP3 polymorphisms were evaluated in the same hospital.

RESULTS

At diagnosis, serum GH concentrations were lower in patients with GHR-d3 genotype than those with GHR-fl, whereas an association of lower IGFBP3 levels with d3 allele was observed only after neurosurgical or medical treatments. However, these associations were not confirmed in posterior statistical analysis.

CONCLUSION

Our results suggest that GHR-exon 3 and -202 A/C IGFBP3 polymorphisms did not show any consistent association on clinical and laboratorial features of acromegalic patients even after treatment.

Evaluation of Downstream Regulatory Element Antagonistic Modulator Gene in Human Multinodular Goiter

Background

DREAM (Downstream Regulatory Element Antagonistic Modulator) is a neuronal calcium sensor that was suggested to modulate TSH receptor activity and whose overexpression provokes an enlargement of the thyroid gland in transgenic mice. The aim of this study was to investigate somatic mutations and DREAM gene expression in human multinodular goiter (MNG).

Material/Methods

DNA and RNA samples were obtained from hyperplastic thyroid glands of 60 patients (54 females) with benign MNG. DREAM mutations were evaluated by PCR and direct automatic sequencing, whereas relative quantification of mRNA was performed by real-time PCR. Over- and under-expression were defined as a 2-fold increase and decrease in comparison to normal thyroid tissue, respectively. RQ M (relative quantification mean); SD (standard deviation).

Results

DREAM expression was detected in all nodules evaluated. DREAM mRNA was overexpressed in 31.7% of MNG (RQ M=6.26; SD=5.08), whereas 53.3% and 15% had either normal (RQ M=1.16; SD=0.46) or underexpression (RQ M=0.30; SD=0.10), respectively. Regarding DREAM mutations analysis, only previously described intronic polymorphisms were observed.

Conclusions

We report DREAM gene expression in the hyperplastic thyroid gland of MNG patients. However, DREAM expression did not vary significantly, and was somewhat underexpressed in most patients, suggesting that DREAM upregulation does not significantly affect nodular development in human goiter.

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.

Study of the association between 3111T/C polymorphism of the CLOCK gene and the presence of overweight in schoolchildren

OBJECTIVES

To evaluate the association between 3111T/C polymorphism of the CLOCK gene and the presence of obesity and sleep duration in children aged 6-13 years. In adults, this genetic variant has been associated with duration of sleep, ghrelin levels, weight, and eating habits. Although short sleep duration has been linked to obesity in children, no study has aimed to identify the possible molecular mechanisms of this association to date.

METHODS

Weight, height, and circumferences were transformed into Z-scores for age and gender. Genotyping was performed using TaqMan methodology. A questionnaire regarding hours of sleep was provided to parents. The appropriate statistical tests were performed.

RESULTS

This study evaluated 370 children (45% males, 55% females, mean age 8.5 ± 1.5 years). The prevalence of overweight was 18%. The duration of sleep was, on average, 9.7hours, and was inversely related to age (p<0.001). Genotype distribution was: 4% CC, 31% CT, and 65% TT. There was a trend toward higher prevalence of overweight in children who slept less than nine hours (23%) when compared to those who slept more than ten hours (16%, p=0.06). Genotype was not significantly correlated to any of the assessed outcomes.

CONCLUSIONS

The CLOCK 3111T/C polymorphism was not significantly associated with overweight or sleep duration in children in this city.

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

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.

OBJECTIVE

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).

DESIGN AND PATIENTS

Genotypes were correlated with adult height data of 65 Turner syndrome (TS) and 47 GH deficiency (GHD) patients treated with rhGH, by multiple linear regressions. Generalized multifactor dimensionality reduction was used to evaluate gene-gene interactions.

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 and GHD after long-term rhGH therapy. Polymorphisms located in GHR, 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.

Role of gonadotropin-releasing hormone receptor mutations in patients with a wide spectrum of pubertal delay

OBJECTIVE

To analyze the GNRHR in patients with normosmic isolated hypogonadotropic hypogonadism (IHH) and constitutional delay of growth and puberty (CDGP).

DESIGN

Molecular analysis and in vitro experiments correlated with phenotype.

SETTING

Academic medical center.

PATIENT(S)

A total of 110 individuals with normosmic IHH (74 male patients) and 50 with CDGP.

INTERVENTION(S)

GNRHR coding region was amplified and sequenced.

MAIN OUTCOME MEASURE(S)

Novel variants were submitted to in vitro analysis. Frequency of mutations and genotype-phenotype correlation were analyzed. Microsatellite markers flanking GNRHR were examined in patients carrying the same mutation to investigate a possible founder effect.

RESULT(S)

Eleven IHH patients (10%) carried biallelic GNRHR mutations. In vitro analysis of novel variants (p.Y283H and p.V134G) demonstrated complete inactivation. The founder effect study revealed that Brazilian patients carrying the p.R139H mutation shared the same haplotype. Phenotypic spectrum in patients with GNRHR mutations varied from complete GnRH deficiency to partial and reversible IHH, with a relatively good genotype-phenotype correlation. One boy with CDGP was heterozygous for the p.Q106R variant, which was not considered to be pathogenic.

CONCLUSION(S)

GNRHR mutations are a frequent cause of congenital normosmic IHH and should be the first candidate gene for genetic screening in this condition, especially in autosomal recessive familial cases. The founder effect study suggested that the p.R139H mutation arises from a common ancestor in the Brazilian population. Finally, mutations in GNRHR do not appear to be involved in the pathogenesis of CDGP.

Incidental mild hyperglycemia in children: two MODY 2 families identified in Brazilian subjects

Maturity-onset diabetes of the young (MODY) is characterized by an autosomal dominant mode of inheritance, early onset of hyperglycemia, and defects of insulin secretion. MODY subtypes described present genetic, metabolic, and clinical differences. MODY 2 is characterized by mild asymptomatic fasting hyperglycemia, and rarely requires pharmacological treatment. Hence, precise diagnosis of MODY is important for determining management and prognosis. We report two heterozygous GCK mutations identified during the investigation of short stature. Case 1: a prepubertal 14-year-old boy was evaluated for constitutional delay of growth and puberty. During follow-up, he showed abnormal fasting glucose (113 mg/dL), increased level of HbA1c (6.6%), and negative β-cell antibodies. His father and two siblings also had slightly elevated blood glucose levels. The mother had normal glycemia. A GCK heterozygous missense mutation, p.Arg191Trp, was identified in the proband. Eighteen family members were screened for this mutation, and 11 had the mutation in heterozygous state. Case 2: a 4-year-old boy investigated for short stature revealed no other laboratorial alterations than elevated glycemia (118 mg/dL); β-cell antibodies were negative. His father, a paternal aunt, and the paternal grandmother also had slightly elevated glycemia, whereas his mother had normal glycemia. A GCK heterozygous missense mutation, p.Glu221Lys, was identified in the index patient and in four family members. All affected patients had mild elevated glycemia. Individuals with normal glycemia did not harbor mutations. GCK mutation screening should be considered in patients with chronic mild early-onset hyperglycemia, family history of impaired glycemia, and negative β-cell antibodies.

Mutational analysis of TAC3 and TACR3 genes in patients with idiopathic central pubertal disorders

OBJECTIVE

To investigate the presence of variants in the TAC3 and TACR3 genes, which encode NKB and its receptor (NK3R), respectively, in a large cohort of patients with idiopathic central pubertal disorders.

SUBJECTS AND METHODS

Two hundred and thirty seven patients were studied: 114 with central precocious puberty (CPP), 73 with normosmic isolated hypogonadotropic hypogonadism (IHH), and 50 with constitutional delay of growth and puberty (CDGP). The control group consisted of 150 Brazilian individuals with normal pubertal development. Genomic DNA was extracted from peripheral blood and the entire coding region of both TAC3 and TACR3 genes were amplified and automatically sequenced.

RESULTS

We identified one variant (p.A63P) in NKB and four variants, p.G18D, p.L58L (c.172C>T), p.W275* and p.A449S in NK3R, which were absent in the control group. The p.A63P variant was identified in a girl with CPP, and p.A449S in a girl with CDGP. The known p.G18D, p.L58L, and p.W275* variants were identified in three unrelated males with normosmic IHH.

CONCLUSION

Rare variants in the TAC3 and TACR3 genes were identified in patients with central pubertal disorders. Loss-of-function variants of TACR3 were associated with the normosmic IHH phenotype.

GH-releasing hormone receptor gene: a novel splice-disrupting mutation and study of founder effects

BACKGROUND

Mutations in GH-releasing hormone receptor gene (GHRHR) are emerging as the most common cause of autosomal recessive isolated GH deficiency (IGHD).

OBJECTIVE

To search for GHRHR mutations in patients with familial or sporadic IGHD and to investigate founder effects in recurring mutations.

METHODS

The coding region of GHRHR 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 GHRHR 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.

RESULTS

A novel homozygous intronic GHRHR 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.

CONCLUSION

We report a novel splice-disrupting mutation in GHRHR 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.

Novel mutation in the gonadotropin-releasing hormone receptor (GNRHR) gene in a patient with normosmic isolated hypogonadotropic hypogonadism

We report a novel GNRHR mutation in a male with normosmic isolated hypogonadotropic hypogonadism (nIHH). The coding region of the GNRHR gene was amplified and sequenced. Three variants p.[Asn10Lys;Gln11Lys]; [Tyr283His] were identified in the GNRHR coding region in a male with sporadic complete nIHH. The three variants were absent in the controls (130 normal adults). Familial segregation showed that the previously described p.Asn10Lys and p.Gln11Lys are in the same allele, in compound heterozygozity with the novel variant p.Tyr283His. The p.[Asn10Lys;Gln11Lys] are known inactivating mutations. The p.Tyr283His affects a well-conserved residue, and in silico analysis suggested it is a deleterious variant. We describe a novel GNRHR mutation in a male with nIHH. Absence of the mutation in the control group, conservation among species, in silico analysis, and familial segregation suggest that p.Tyr283His, which was identified in compound heterozygozity with the p.[Asn10Lys;Gln11Lys] variants, is an inactivating mutation. Arq Bras Endocrinol Metab. 2012;56(8):540-4

The interactive effect of GHR-exon 3 and -202 A/C IGFBP3 polymorphisms on rhGH responsiveness and treatment outcomes in patients with Turner syndrome

CONTEXT

There is great interindividual variability in the response to recombinant human (rh) GH therapy in patients with Turner syndrome (TS). Ascertaining genetic factors can improve the accuracy of growth response predictions.

OBJECTIVE

The objective of the study was to assess the individual and combined influence of GHR-exon 3 and -202 A/C IGFBP3 polymorphisms on the short- and long-term outcomes of rhGH therapy in patients with TS.

DESIGN AND PATIENTS

GHR-exon 3 and -202 A/C IGFBP3 genotyping (rs2854744) was correlated with height data of 112 patients with TS who remained prepubertal during the first year of rhGH therapy and 65 patients who reached adult height after 5 ± 2.5 yr of rhGH treatment.

MAIN OUTCOME MEASURES

First-year growth velocity and adult height were measured.

RESULTS

Patients carrying at least one GHR-d3 or -202 A-IGFBP3 allele presented higher mean first-year growth velocity and achieved taller adult heights than those homozygous for GHR-fl or -202 C-IGFBP3 alleles, respectively. The combined analysis of GHR-exon 3 and -202 A/C IGFBP3 genotypes showed a clear nonadditive epistatic influence on adult height of patients with TS treated with rhGH (GHR-exon 3 alone, R² = 0.27; -202 A/C IGFBP3, R² = 0.24; the combined genotypes, R² = 0.37 at multiple linear regression). Together with clinical factors, these genotypes accounted for 61% of the variability in adult height of patients with TS after rhGH therapy.

CONCLUSION

Homozygosity for the GHR-exon3 full-length allele and/or the -202C-IGFBP3 allele are associated with less favorable short- and long-term growth outcomes after rhGH treatment in patients with TS.

Nonsense mutations in FGF8 gene causing different degrees of human gonadotropin-releasing deficiency

CONTEXT

FGFR1 mutations cause isolated hypogonadotropic hypogonadism (IHH) with or without olfactory abnormalities, Kallmann syndrome, and normosmic IHH respectively. Recently, missense mutations in FGF8, a key ligand for fibroblast growth factor receptor (FGFR) 1 in the ontogenesis of GnRH, were identified in IHH patients, thus establishing FGF8 as a novel locus for human GnRH deficiency.

OBJECTIVE

Our objective was to analyze the clinical, hormonal, and molecular findings of two familial IHH patients due to FGF8 gene mutations.

METHODS AND PATIENTS

The entire coding region of the FGF8 gene was amplified and sequenced in two well-phenotyped IHH probands and their relatives.

RESULTS

Two unique heterozygous nonsense mutations in FGF8 (p.R127X and p.R129X) were identified in two unrelated IHH probands, which were absent in 150 control individuals. These two mutations, mapped to the core domain of FGF8, impact all four human FGF8 isoforms, and lead to the deletion of a large portion of the protein, generating nonfunctional FGF8 ligands. The p.R127X mutation was identified in an 18-yr-old Kallmann syndrome female. Her four affected siblings with normosmic IHH or delayed puberty also carried the p.R127X mutation. Additional developmental anomalies, including cleft lip and palate and neurosensorial deafness, were also present in this family. The p.R129X mutation was identified in a 30-yr-old man with familial normosmic IHH and severe GnRH deficiency.

CONCLUSIONS

We identified the first nonsense mutations in the FGF8 gene in familial IHH with variable degrees of GnRH deficiency and olfactory phenotypes, confirming that loss-of-function mutations in FGF8 cause human GnRH deficiency.

A novel homozygous splice acceptor site mutation of KISS1R in two siblings with normosmic isolated hypogonadotropic hypogonadism

CONTEXT

Loss-of-function mutations of the kisspeptin-1 receptor gene, KISS1R, have been identified in patients with normosmic isolated hypogonadotropic hypogonadism (nIHH).

OBJECTIVE

To investigate KISS1R defects in patients with absent or delayed puberty.

PATIENTS

We investigated KISS1R gene defects in a cohort of 99 Brazilian patients with nIHH or constitutional delay of puberty (CDP).

METHODS

The entire coding region of KISS1R was amplified by PCR followed by automatic sequencing. In addition, screening for KISS1R exonic deletions was performed by multiplex ligation-dependent probe amplification.

RESULTS

One novel homozygous KISS1R mutation was identified in two siblings with nIHH. This variant was an insertion/deletion (indel) mutation characterized by the deletion of three nucleotides (GCA) at position -2 to -4, and by the insertion of seven nucleotides (ACCGGCT) at the same position, within the 3' splice acceptor site of intron 2 of KISS1R. The brothers who carried this KISS1R mutation had no clinical evidence of pubertal development at the ages of 14 and 20 years. Computational analysis of this indel mutation predicted the generation of an abnormal protein. In addition, a new heterozygous KISS1R variant (p.E252Q) was identified in a male patient with sporadic nIHH. However, in vitro studies of this variant did not demonstrate functional impairment. Only known polymorphisms were identified in patients with CDP.

CONCLUSION

Loss-of-function mutations of KISS1R represents a rare cause of nIHH, and was absent in patients with CDP. We have described a novel KISS1R homozygous splice acceptor site mutation in the familial form of nIHH.

A GPR54-activating mutation in a patient with central precocious puberty

Gonadotropin-dependent, or central, precocious puberty is caused by early maturation of the hypothalamic-pituitary-gonadal axis. In girls, this condition is most often idiopathic. Recently, a G protein-coupled receptor, GPR54, and its ligand, kisspeptin, were described as an excitatory neuroregulator system for the secretion of gonadotropin-releasing hormone (GnRH). In this study, we have identified an autosomal dominant GPR54 mutation--the substitution of proline for arginine at codon 386 (Arg386Pro)--in an adopted girl with idiopathic central precocious puberty (whose biologic family was not available for genetic studies). In vitro studies have shown that this mutation leads to prolonged activation of intracellular signaling pathways in response to kisspeptin. The Arg386Pro mutant appears to be associated with central precocious puberty.

Molecular analysis of KAL-1, GnRH-R, NELF and EBF2 genes in a series of Kallmann syndrome and normosmic hypogonadotropic hypogonadism patients

We report the results of molecular analysis in a series of twelve Kallmann syndrome (KS) and five normosmic hypogonadotropic hypogonadism (nHH) Brazilian patients. Kallman syndrome 1 (KAL-1) gene analysis was performed in all patients and the gonadotrophin releasing hormone receptor (GnRH-R) gene was investigated in nHH patients using PCR analysis with exon-flanking primers followed by automated sequencing techniques. Two-point mutations at the KAL-1 locus were found in two KS patients. One case exhibited a novel C deletion (del1956C) in exon 12 leading to a premature stop codon at position 617. The second case, a C to T transition at exon 5, showed a stop codon at aminoacid 191 (Arg191X). Renal agenesis and bimanual synkinesis, which are frequently found in patients with the KAL-1 mutation, were observed in these cases. Among the KS patients, two previously reported cases had intragenic deletions of exons 5-10, while a third patient had a KAL-1 gene microdeletion detected by fluorescence in situ hybridization. For the nHH patients, no abnormalities were observed at the exonic and flanking sequences of the KAL-1 or GnRH-R genes. Nasal embryonic LHRH factor (NELF) and early B-cell factor 2 (EBF2) exons were evaluated in KAL-1/GnRH-R mutation-negative cases (seven KS and five nHH) by sequence analysis but no mutations were identified in the coding regions in these patients. In conclusion, this report includes the description of a novel point mutation of the KAL-1 gene and suggests that the KAL-1 mutations and deletions might be more prevalent in KS Brazilian patients than previously described in other series. NELF and EBF2 genes have been considered good candidates for HH and a large number of patients need to be studied to assess their contribution to reproductive function.

Cytogenetic analysis and detection of KAL-1 gene deletion with fluorescence in situ hybridization (FISH) in patients with Kallmann syndrome

Kallmann syndrome (KS) is a disease clinically characterized by the association of hypogonadotropic hypogonadism and anosmia or hyposmia, for which three modes of transmission have been described: X-linked, autosomal recessive and autosomal dominant. The KAL-1 gene, responsible for the X-linked form of the disease, has been isolated and its intron-exon organization determined. In this study, two families with X-linked KS and four sporadic male patients with hypogonadotropic hypogonadism and anosmia were cytogenetically investigated with high-resolution techniques and FISH. Chromosomal analysis did not reveal any rearrangements or deletions. Deletion of the KAL-1 gene was detected by FISH in only one sporadic patient, with the typical features of KS and a high palate. Among the familial cases renal abnormalities and pes cavus deformity were observed.