FGFR1 Variants Research Articles

Digenic Variants in the FGF21 Signaling Pathway Associated with Severe Insulin Resistance and Pseudoacromegaly.

Insulin-mediated pseudoacromegaly (IMPA) is a rare disease of unknown etiology. Here we report a 12-year-old female with acanthosis nigricans, hirsutism, and acromegalic features characteristic of IMPA. The subject was noted to have normal growth hormone secretion, with extremely elevated insulin levels. Studies were undertaken to determine a potential genetic etiology for IMPA. The proband and her family members underwent whole exome sequencing. Functional studies were undertaken to validate the pathogenicity of candidate variant alleles. Whole exome sequencing identified monoallelic, predicted deleterious variants in genes that mediate fibroblast growth factor 21 (FGF21) signaling, FGFR1 and KLB, which were inherited in trans from each parent. FGF21 has multiple metabolic functions but no known role in human insulin resistance syndromes. Analysis of the function of the FGFR1 and KLB variants in vitro showed greatly attenuated ERK phosphorylation in response to FGF21, but not FGF2, suggesting that these variants act synergistically to inhibit endocrine FGF21 signaling but not canonical FGF2 signaling. Therefore, digenic variants in FGFR1 and KLB provide a potential explanation for the subject’s severe insulin resistance and may represent a novel category of insulin resistance syndromes related to FGF21.

GnRH Deficient Patients With Congenital Hypogonadotropic Hypogonadism: Novel Genetic Findings in ANOS1, RNF216, WDR11, FGFR1, CHD7, and POLR3A Genes in a Case Series and Review of the Literature.

Background: Congenital hypogonadotropic hypogonadism (CHH) is a rare genetic disease caused by Gonadotropin-Releasing Hormone (GnRH) deficiency. So far a limited number of variants in several genes have been associated with the pathogenesis of the disease. In this original research and review manuscript the retrospective analysis of known variants in ANOS1 (KAL1), RNF216, WDR11, FGFR1, CHD7, and POLR3A genes is described, along with novel variants identified in patients with CHH by the present study.Methods: Seven GnRH deficient unrelated Cypriot patients underwent whole exome sequencing (WES) by Next Generation Sequencing (NGS). The identified novel variants were initially examined by in silico computational algorithms and structural analysis of their predicted pathogenicity at the protein level was confirmed.Results: In four non-related GnRH males, a novel X-linked pathogenic variant in ANOS1 gene, two novel autosomal dominant (AD) probably pathogenic variants in WDR11 and FGFR1 genes and one rare AD probably pathogenic variant in CHD7 gene were identified. A rare autosomal recessive (AR) variant in the SRA1 gene was identified in homozygosity in a female patient, whilst two other male patients were also, respectively, found to carry novel or previously reported rare pathogenic variants in more than one genes; FGFR1/POLR3A and SRA1/RNF216.Conclusion: This report embraces the description of novel and previously reported rare pathogenic variants in a series of genes known to be implicated in the biological development of CHH. Notably, patients with CHH can harbor pathogenic rare variants in more than one gene which raises the hypothesis of locus-locus interactions providing evidence for digenic inheritance. The identification of such aberrations by NGS can be very informative for the management and future planning of these patients.

Abstract 5895: Whole-genome characterization of lung adenocarcinomas lacking alterations in RTK/RAS/RAF/MAPK pathway

Abstract Lung adenocarcinomas (LUAD) are typically characterized by genetic activation of the receptor tyrosine kinase (RTK)/RAS/RAF/MAP kinase (MAPK) pathway. A minority of LUAD cases (20-25%) lack apparent genetic alterations in this pathway, and thus are ineligible for most targeted therapies. These candidate “oncogene negative” LUADs may harbor novel classes of oncogenic drivers or represent a biologically distinct class of tumors. To characterize the genomic landscape of oncogene-negative LUADs, we nominated 98 cases that were found to lack an activating RTK/RAS/RAF/MAPK pathway alteration in a TCGA study utilizing whole exome sequencing, microarray, and transcriptome data. We profiled these tumors with high-depth whole genome sequencing (WGS), with the goal of identifying noncoding and structural variant driver DNA alterations in both known and novel loci. Of the 98 cases, 20 harbored somatic KRAS mutations that had been missed in the prior WES and transcriptome studies because of insufficient coverage, including 8 cases with the recently targetable p.G12C mutation. 16 samples harbored oncogenic or loss-of-function structural variants in FGFR1, MAPK1, EGFR, NF1, RASA1, ARAF, NTRK2 and NRG1. 5 other samples with SNV or indels in EGFR, ERBB2 and SOS1 were reclassified as oncogene positive. Thus via comprehensive genomic analysis, we confirmed that 57 of the 98 WGS cases did not harbor any detectable alterations in genes encoding any known RTK/RAS/RAF/MAPK members, representing 13% cases chosen as “lung adenocarcinomas” for the TCGA study. Among the 57 confirmed oncogene-negative LUADs, we identified focal deletions targeting the promoter and transcription start site of tumor suppressor genes STK11, KEAP1 and SMARCA4 in 10 samples. Expression and methylation profiling suggested an enrichment of the TP53-deficient phenotype, including cell cycle and FOXM1 deregulation, among the oncogene-negative samples. Moreover, novel promoter mutations associated with increased expression were identified in ILF2, which regulates DNA damage response pathways. Finally, a subset of confirmed oncogene-negative LUADs harbored increased expression of neuroendocrine markers, suggesting that these oncogene-negative samples may either be mis-diagnosed as LUAD or represent LUAD with mixed features of other subtypes of lung cancer; indeed, 14 of the 57 confirmed oncogene-negative cases show histological features of large cell neuroendocrine lung carcinoma. This would suggest that 10% of the cases in this study are both lung adenocarcinoma and “oncogene-negative” to date. Our results provide some of the first comprehensive genomic characterization of oncogene-negative LUADs, implicating TP53 and structural variants in the pathogenesis of this common and difficult to treat entity. Citation Format: Jian Carrot-Zhang, Siddhartha Devarakonda, Nicolas Robine, Xiaotong Yao, Tiago C. Silva, Jeff Damrauer, Aditya Deshpande, Ming-Sound Tsao, Christina Yao, Chris Wong, Lisui Bao, Hyo Young Choi, Ina Felau, Jean C. Zenklusen, Gordon Robertson, Tuan Trieua, Wei-Wei Liang, Meng Zhou, Esther Rheinbay, Neil Hayes, Ekta Khurana, Li Ding, Peter Laird, Olivier Elemento, John Weinstein, David Kwiatkowski, Chris Benz, Josh Stuart, Lixing Yang, Mauro Castro, William Travis, Katherine Hoadley, Ben Berman, TCGA Analysis Network, Matthew Meyerson, Ramaswamy Govindan, Marcin Imielinski. Whole-genome characterization of lung adenocarcinomas lacking alterations in RTK/RAS/RAF/MAPK pathway [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5895.

Abstract 3748: Tyrosine kinase inhibition of fibroblast growth factor receptor 1 in advanced prostate cancer

Abstract Advanced prostate cancer (PCa) is one of the leading causes of cancer death in men in the United States. The FGF/FGFR1 signaling axis has been implicated in the progression of PCa. Different isoforms of FGFR1 have been described in PCa (e.g., alpha and beta), which might account for the typical heterogeneity of PCa. The isoforms may also mediate different clinical responses to treatments targeting this pathway. Pan-FGFR tyrosine kinase inhibitor JNJ-42756493 (Janssen) has been demonstrated to have antiproliferative effects in FGFR pathway-activated cancer cell lines and in vivo mouse antitumor activity. Our goal was to study the effects of JNJ-42756493 in PCa growth and signaling in vitro and establish whether these effects differ according to the FGFR1 isoform (alpha or beta) expressed. Using transfected bone-derived PCa cell lines and patient-derived xenografts (PDXs), we measured the effects of FGFR1 expression on cell proliferation and activation of the FGFR1-pMAPK signaling pathway. We then performed drug treatment experiments on FGFR1-expressing sublines and high-FGFR1 PDXs and observed the response in FGFR1-pMAPK signaling pathway activation. Our results showed that FGFR1 isoforms alpha and beta trigger different biological effects (i.e., proliferation), possibly contributing to the heterogeneity of PCa. We found that targeting the tyrosine kinase domain of FGFR1 with JNJ-42756493 results in pMAPK inhibition in PCa sublines. These findings indicate that the presence of specific FGFR1 variants should be considered for treatment selection in advanced PCa. The results also suggest that FGFR1-pMAPK pathway blockade by JNJ-42756493 should be further studied as a strategy to guide the development of therapies to hinder PCa progression. Citation Format: Louise Medina Bengtsson, Estefania Labanca, Nora Navone. Tyrosine kinase inhibition of fibroblast growth factor receptor 1 in advanced prostate cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3748.

Novel missense variants in FGFR1 and FGFR3 causes short stature in enrolled families from Pakistan

Dwarfism or short stature is a condition when human height is less than 147 cm in adult form. We enrolled two families with multiple siblings suffering from dwarfism and Whole exome sequencing (WES) followed by Sanger sequencing approach was used to report genetic base of their dwarfism. Two novel missense mutations, c.2407C > A, p.Pro803Thr in FGFR1 gene in family one and c.1779C > G, p.F539L in FGFR3 gene in second family were identified as the genetic cause of their phenotype. Sanger sequencing confirmed these mutations in all enrolled patients and mutations followed autosomal dominant mode of inheritance. Multiple sequence alignment by Clustal Omega revealed that domains of FGFR1 and FGFR3 containing mutations are highly conserved. Computational 3D structure generations through homology modeling approach revealed no observable differences in FGFR1 and FGFR3 protein structures when compared between control and patients indicating that observed mutations are responsible for functional changes in proteins.

Functional Characteristics of Novel FGFR1 Mutations in Patients with Isolated Gonadotropin-Releasing Hormone Deficiency.

Isolated gonadotropin-releasing hormone (GnRH) deficiency (IGD) has a wide phenotypic spectrum including Kallmann syndrome (KS) and normosmic idiopathic hypogonadotropic hypogonadism (nIHH). FGFR1 mutations have been identified in 3-10% of patients with KS or nIHH. This study was performed to investigate clinical phenotypes and functional characteristics of FGFR1 mutations in patients with IGD. This study included 8 patients (from 7 families) with FGFR1 mutations identified by targeted gene panel sequencing or whole exome sequencing (WES). The impact of the identified mutations on FGFR1 function was assessed using in vitro studies. Seven heterozygous mutations in FGFR1 were identified in 8 patients from 7 independent families. The patients exhibited a wide spectrum of pubertal development, including anosmia in a prepubertal boy (n=1), delayed puberty (n=2), nIHH (n=3), and KS (n=2). Four of the mutations were classified as likely pathogenic, and the other three were variants of uncertain significance. FGF8-FGFR1 signaling activities for the novel FGFR1 variants (p.Y339H, p.S681I, and p.N185Kfs*16) were reduced by in vitro functional assay, indicating loss-of-function mutations. This study identified seven rare sequence variants in FGFR1 in patients with KS and nIHH. Probands with an FGFR1 mutations displayed a wide phenotypic spectrum ranging from KS to anosmia. A prepubertal male with anosmia should be followed up to assess pubertal development because they can manifest hypogonadotropic hypogonadism after puberty. These results expand the phenotypic spectrum of FGFR1 mutations and suggest a broader biologic role of FGFR1 in reproduction.

Expanding the mutational spectrum of monogenic hypogonadotropic hypogonadism: novel mutations in ANOS1 and FGFR1 genes

BackgroundCongenital hypogonadotropic hypogonadism (CHH) is a rare disease, triggered by defective GnRH secretion, that is usually diagnosed in late adolescence or early adulthood due to the lack of spontaneous pubertal development. To date more than 30 genes have been associated with CHH pathogenesis with X-linked recessive, autosomal dominant, autosomal recessive and oligogenic modes of inheritance. Defective sense of smell is present in about 50–60% of CHH patients and called Kallmann syndrome (KS), in contrast to patients with normal sense of smell referred to as normosmic CHH.ANOS1 and FGFR1 genes are all well established in the pathogenesis of CHH and have been extensively studied in many reported cohorts. Due to rarity and heterogenicity of the condition the mutational spectrum, even in classical CHH genes, have yet to be fully characterized.MethodsTo address this issue we screened for ANOS1 and FGFR1 variants in a cohort of 47 unrelated CHH subjects using targeted panel sequencing. All potentially pathogenic variants have been validated with Sanger sequencing.ResultsSequencing revealed two ANOS1 and four FGFR1 mutations in six subjects, of which five are novel and one had been previously reported in CHH. Novel variants include a single base pair deletion c.313delT in exon 3 of ANOS1, three missense variants of FGFR1 predicted to result in the single amino acid substitutions c.331C > T (p.R111C), c.1964 T > C (p.L655P) and c.2167G > A (p.E723K) and a 15 bp deletion c.374_388delTGCCCGCAGACTCCG in exon 4 of FGFR1. Based on ACMG–AMP criteria reported variants were assigned to class 5, pathogenic or class 4, likely pathogenic. Protein structural predictions, the rarity of novel variants and amino acid conservation in case of missense substitutions all provide strong evidence that these mutations are highly likely to be deleterious.ConclusionsDespite the fact that ANOS1 and FGFR1 are classical CHH genes and were thoroughly explored in several CHH cohorts we identified new, yet undescribed variants within their sequence. Our results support the genetic complexity of the disorder. The knowledge of the full genetic spectrum of CHH is increasingly important in order to be able to deliver the best personalised medical care to our patients.

Cancer genetics-one family at a time.

This article is a distillation and extension of some of themes I presented as a lecture to the Canadian Society of Clinical Investigation meeting in Banff in 2019. I emphasize the important role that investigation of a few key families seen in our clinic (sometimes as few as one) can play in cancer genetic discovery. I present the work both thematically and chronologically, demonstrating how clinical observation, combined with laboratory work and extensive collaboration can lead to novel insights. I will focus on families possessing germline pathogenic variants in PALB2, DICER1, SMARCA4, FGFR1 and RAD51D as examples of how the process has been carried out in our group.

Novel synonymous and missense variants in FGFR1 causing Hartsfield syndrome

Hartsfield syndrome is a rare clinical entity characterized by holoprosencephaly and ectrodactyly with the variable feature of cleft lip/palate. In addition to these symptoms patients with Hartsfield syndrome can show developmental delay of variable severity, isolated hypogonadotropic hypogonadism, central diabetes insipidus, vertebral anomalies, eye anomalies, and cardiac malformations. Pathogenic variants in FGFR1 have been described to cause phenotypically different FGFR1-related disorders such as Hartsfield syndrome, hypogonadotropic hypogonadism with or without anosmia, Jackson-Weiss syndrome, osteoglophonic dysplasia, Pfeiffer syndrome, and trigonocephaly Type 1. Here, we report three patients with Hartsfield syndrome from two unrelated families. Exome sequencing revealed two siblings harboring a novel de novo heterozygous synonymous variant c.1029G>A, p.Ala343Ala causing a cryptic splice donor site in exon 8 of FGFR1 likely due to gonadal mosaicism in one parent. The third case was a sporadic patient with a novel de novo heterozygous missense variant c.1868A>G, p.(Asp623Gly).

Heterozygous FGFR1 mutation may be responsible for an incomplete form of osteoglophonic dysplasia, characterized only by radiolucent bone lesions and teeth retentions

Non-ossifying fibromas are seen in different disorders recognizable by specific features. Indeed, osteoglophonic dysplasia (OD) is characterized by radiolucent bone lesions associated with severe short stature, dysmorphism and failure of dental eruption. This syndrome is caused by heterozygous activating mutations in the immunoglobulin-like D3 domain of the FGFR1 gene, encoding a tyrosine kinase. Here, we report three patients from the same family presenting with radiolucent bone lesions and teeth retentions. Exome sequencing allowed identification of a novel mutation c.917C > T, p. Pro306Leu in exon 7 of the FGFR1 gene. Our patients present with normal stature and no severe dysmorphism. This report describes a mild form of OD and expands the phenotype related to FGFR1 mutations. These findings emphasize the need to consider FGFR1 variants in the case of multiple non-ossifying bone lesions associated with dental eruption anomalies.

A novel dominant-negative FGFR1 variant causes Hartsfield syndrome by deregulating RAS/ERK1/2 pathway.

Hartsfield syndrome (HS) is an ultrarare developmental disorder mainly featuring holoprosencephaly and ectrodactyly. It is caused by heterozygous or biallelic variants in FGFR1. Recently, a dominant-negative effect was suggested for FGFR1 variants associated with HS. Here, exome sequencing analysis in a 12-year-old boy with HS disclosed a novel de novo heterozygous variant c.1934C>T in FGFR1 predicted to cause the p.(Ala645Val) amino-acid substitution. In order to evaluate whether the variant, changing a highly conserved residue of the kinase domain, affects FGFR1 function, biochemical studies were employed. We measured the FGFR1 receptor activity in FGF2-treated cell lines exogenously expressing wild-type or Ala645Val FGFR1 by monitoring the activation status of FGF2/FGFR1 downstream pathways. Our analysis highlighted that RAS/ERK1/2 signaling was significantly perturbed in cells expressing mutated FGFR1, in comparison with control cells. We also provided preliminary evidence showing a modulation of the autophagic process in cells expressing mutated FGFR1. This study expands the FGFR1 mutational spectrum associated with HS, provides functional evidence further supporting a dominant-negative effect of this category of FGFR1 variants and offers initial insights on dysregulation of autophagy in HS.

Abstract 3602: Validation and implementation of next-generation sequencing in liquid biopsies by a novel NGS platform: Focus on non-small cell lung cancer

Abstract Introduction: Liquid biopsy as a novel and non-invasive test for the surveillance of cancer is rapidly growing, by next-generation sequencing (NGS) technologies with multi-gene panels. Objective: The aim of this study was to describe the validation and implementation of a cell free tumor DNA (cfDNA) from the patients with non-small cell lung cancer (NSCLC), to sequence for 19 genes and copy number variation analyses for 5 genes via a novel NGS platform; GeneReader NGS System. Materials and Methods: We performed the complete NGS workflow with modifications, and sequenced the cfDNA extracted from 100 NSCLC patients. The multi-gene panel includes 19 lung cancer related genes (AKT1, ALK, BRAF, DDR, ERBB2, ESR1, KIT, KRAS, MAP2K1, NRAS, NTRK, PDGFRA, PIK3CA, PTEN and ROS) to sequence and additional copy number variations of 5 genes (RICTOR, EGFR, MET, FGFR1 and ERBB2) that all were selected to represent the most actionable genes for the clinical oncology and molecular diagnostics. The sequencing was performed using a novel NGS platform (GeneReader NGS System, Qiagen). Results: The validation process and the implementation of genetic testing from the cfDNA by this novel NGS system have been utilized for the clinical use. After quality assessment, the data from this NGS system was bioinformatically processed and a tertiary analysis was performed using QCI-Analyze and QCI-Interpret bioinformatics tools. The data was then reviewed on alterations and those reported in different mutation databases. The clinically relevant alterations were identified and reported due to the testing indications. Overall, actionable variants in EGFR, ALK, KRAS, PIK3CA, MET, FGFR1 and ERBB2 genes were detected and reported in 62 % of all NSCLC patients while the majority were in EGFR. Conclusions: For each of the 100 samples tested thus far, at least one variant was detected showing the high sensitivity and specificity of both the multi-gene panel and this novel NGS platform. Our evaluation yielded good results for the actionable multi-gene panel selected and provides a comprehensive NGS analysis and workflow for this new platform. Citation Format: Atil Bisgin, Ozge Sonmezler, Ibrahim Boga. Validation and implementation of next-generation sequencing in liquid biopsies by a novel NGS platform: Focus on non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3602.

Contribution of FGFR1 Variants to Craniofacial Variations in East Asians.

FGFR1 plays an important role in the development of the nervous system as well as the regulation of the skeletal development and bone homeostasis. Mutations in FGFR1 genes affect skull development, specifically suture and synchondrosis, resulting in craniosynostosis and facial abnormalities. We examined subjects with normal skull morphology for genetic polymorphisms that might be associated with normal craniofacial variations. Genomic DNA was obtained from 216 Japanese and 227 Korean subjects. Four FGFR1 SNPs, namely, rs881301, rs6996321, rs4647905, and rs13317, were genotyped. These SNPs were tested for association with craniofacial measurements obtained from lateral and posteroanterior cephalometries, in which principle component analysis was performed to compress the data of the craniofacial measurements. We observed that SNPs rs13317 and rs6996321 were correlated with the overall head size and midfacial development, indicating that FGFR1 SNPs played crucial roles in the normal variation of human craniofacial morphology. Subjects with the derived alleles of SNPs rs13317 and rs6996321 had a small face and a facial pattern associated with a retruded midface and relatively wide-set eyes. These facial features were similar to but were milder than those of individuals with Pfeiffer syndrome, which is caused by a dysfunctional mutation in FGFR1.

Association Between Genes Involved in Craniofacial Development and Nonsyndromic Cleft Lip and/or Palate in the Brazilian Population.

To determine the association of single-nucleotide polymorphisms (SNPs) in genes related to craniofacial development, which were previously identified as susceptibility signals for nonsyndromic oral clefts, in Brazilians with nonsyndromic cleft lip and/or palate (NSCL/P). The SNPs rs748044 (TNP1), rs1106514 (MSX1), rs28372960, rs15251 and rs2569062 (TCOF1), rs7829058 (FGFR1), rs1793949 (COL2A1), rs11653738 (WNT3), and rs242082 (TIMP3) were assessed in a family-based transmission disequilibrium test (TDT) and a structured case-control analysis based on the individual ancestry proportions. The SNPs were initially analyzed by TDT, and polymorphisms showing a trend toward excess transmission were subsequently studied in an independent case-control sample. The study sample consisted of 189 case-parent trios of nonsyndromic cleft lip with or without cleft palate (NSCL±P), 107 case-parent trios of nonsyndromic cleft palate (NSCP), 318 isolated samples of NSCL±P, 189 isolated samples of NSCP, and 599 healthy controls. Association of alleles with NSCL/P pathogenesis. Preferential transmission of SNPs rs28372960 and rs7829058 in NSCL±P trios and rs11653738 in NSCP trios (P = .04) were observed, although the structured case-control analysis did not confirm these associations. The haplotype T-C-C formed by TCOF1 SNPs rs28372960, rs15251, and rs2569062 was more frequently transmitted from healthy parents to NSCL±P offspring, but the P value (P = .01) did not withstand Bonferroni correction for multiple tests. With the modest associations, our results do not support the hypothesis that TNP1, MSX1, TCOF1, FGFR1, COL2A1, WNT3, and TIMP3 variants are risk factors for nonsyndromic oral clefts in the Brazilian population.

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 Ca2 + 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.

Expanding the Phenotype and Genotype of Female GnRH Deficiency

Abstract Context: GnRH deficiency is a rare genetic disorder of absent or partial pubertal development. The clinical and genetic characteristics of GnRH-deficient women have not been well-described. Objective: To determine the phenotypic and genotypic spectrum of a large series of GnRH-deficient women. Design, Setting, and Subjects: Retrospective study of 248 females with GnRH deficiency evaluated at an academic medical center between 1980 and 2010. Main Outcome Measures: Clinical presentation, baseline endogenous GnRH secretory activity, and DNA sequence variants in 11 genes associated with GnRH deficiency. Results: Eighty-eight percent had undergone pubarche, 51% had spontaneous thelarche, and 10% had 1-2 menses. Women with spontaneous thelarche were more likely to demonstrate normal pubarche (P = 0.04). In 27% of women, neuroendocrine studies demonstrated evidence of some endogenous GnRH secretory activity. Thirty-six percent (a large excess relative to controls) harbored a rare sequence variant in a gene associated with GnRH deficiency (87% heterozygous and 13% biallelic), with variants in FGFR1 (15%), GNRHR (6.6%), and PROKR2 (6.6%) being most prevalent. One woman had a biallelic variant in the X-linked gene, KAL1, and nine women had heterozygous variants. Conclusions: The clinical presentation of female GnRH deficiency varies from primary amenorrhea and absence of any secondary sexual characteristics to spontaneous breast development and occasional menses. In this cohort, rare sequence variants were present in all of the known genes associated with GnRH deficiency, including the novel identification of GnRH-deficient women with KAL1 variants. The pathogenic mechanism through which KAL1 variants disrupt female reproductive development requires further investigation.

Expanding the Phenotype and Genotype of Female GnRH Deficiency

GnRH deficiency is a rare genetic disorder of absent or partial pubertal development. The clinical and genetic characteristics of GnRH-deficient women have not been well-described. To determine the phenotypic and genotypic spectrum of a large series of GnRH-deficient women. Retrospective study of 248 females with GnRH deficiency evaluated at an academic medical center between 1980 and 2010. Clinical presentation, baseline endogenous GnRH secretory activity, and DNA sequence variants in 11 genes associated with GnRH deficiency. Eighty-eight percent had undergone pubarche, 51% had spontaneous thelarche, and 10% had 1-2 menses. Women with spontaneous thelarche were more likely to demonstrate normal pubarche (P = 0.04). In 27% of women, neuroendocrine studies demonstrated evidence of some endogenous GnRH secretory activity. Thirty-six percent (a large excess relative to controls) harbored a rare sequence variant in a gene associated with GnRH deficiency (87% heterozygous and 13% biallelic), with variants in FGFR1 (15%), GNRHR (6.6%), and PROKR2 (6.6%) being most prevalent. One woman had a biallelic variant in the X-linked gene, KAL1, and nine women had heterozygous variants. The clinical presentation of female GnRH deficiency varies from primary amenorrhea and absence of any secondary sexual characteristics to spontaneous breast development and occasional menses. In this cohort, rare sequence variants were present in all of the known genes associated with GnRH deficiency, including the novel identification of GnRH-deficient women with KAL1 variants. The pathogenic mechanism through which KAL1 variants disrupt female reproductive development requires further investigation.

FGF/FGFR signaling pathway in autism: Identification of a novel mutation in FGF2 gene and association of FGF2, FGFR1, FGFR2 and FGFR3 genetic variants in a Portuguese population sample

International Journal of Developmental NeuroscienceVolume 28, Issue 8 p. 714-714 Article [P2.78]: FGF/FGFR signaling pathway in autism: Identification of a novel mutation in FGF2 gene and association of FGF2, FGFR1, FGFR2 and FGFR3 genetic variants in a Portuguese population sample A. Sequeira, Corresponding Author A. Sequeira n/[email protected] Instituto Gulbenkian de Ciência, Portugal Instituto Nacional de Saúde, PortugalSearch for more papers by this authorM. Gilling, M. Gilling University of Copenhagen, DenmarkSearch for more papers by this authorT. Magalhães, T. Magalhães Instituto Gulbenkian de Ciência, Portugal Instituto Nacional de Saúde, PortugalSearch for more papers by this authorC. Correia, C. Correia Instituto Gulbenkian de Ciência, Portugal Instituto Nacional de Saúde, PortugalSearch for more papers by this authorG. Oliveira, G. Oliveira Hospital Pediátrico de Coimbra, PortugalSearch for more papers by this authorA. Vicente, A. Vicente Instituto Gulbenkian de Ciência, Portugal Instituto Nacional de Saúde, PortugalSearch for more papers by this author A. Sequeira, Corresponding Author A. Sequeira n/[email protected] Instituto Gulbenkian de Ciência, Portugal Instituto Nacional de Saúde, PortugalSearch for more papers by this authorM. Gilling, M. Gilling University of Copenhagen, DenmarkSearch for more papers by this authorT. Magalhães, T. Magalhães Instituto Gulbenkian de Ciência, Portugal Instituto Nacional de Saúde, PortugalSearch for more papers by this authorC. Correia, C. Correia Instituto Gulbenkian de Ciência, Portugal Instituto Nacional de Saúde, PortugalSearch for more papers by this authorG. Oliveira, G. Oliveira Hospital Pediátrico de Coimbra, PortugalSearch for more papers by this authorA. Vicente, A. Vicente Instituto Gulbenkian de Ciência, Portugal Instituto Nacional de Saúde, PortugalSearch for more papers by this author First published: 01 November 2010 https://doi.org/10.1016/j.ijdevneu.2010.07.208Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume28, Issue8Abstracts to the 18th Biennial Meeting of the International Society for Developmental Neuroscience, 6‐9 June 2010, Estoril, PortugalDecember 2010Pages 714-714 RelatedInformation

Expression of fibroblast growth factor receptors during development and regression of the bovine corpus luteum

There is evidence that fibroblast growth factors (FGFs) are involved in the regulation of growth and regression of the corpus luteum (CL). However, the expression pattern of most FGF receptors (FGFRs) during CL lifespan is still unknown. The objective of the present study was to determine the pattern of expression of 'B' and 'C' splice variants of FGFRs in the bovine CL. Bovine CL were collected from an abattoir and classed as corpora hemorrhagica (Stage I), developing (Stage II), developed (Stage III) or regressed (Stage IV) CL. Expression of FGFR mRNA was measured by semiquantitative reverse transcription-polymerase chain reaction and FGFR protein was localised by immunohistochemistry. Expression of mRNA encoding the 'B' and 'C' spliced forms of FGFR1 and FGFR2 was readily detectable in the bovine CL and was accompanied by protein localisation. FGFR1C and FGFR2C mRNA expression did not vary throughout CL lifespan, whereas FGFR1B was upregulated in the developed (Stage III) CL. FGFR3B, FGFR3C and FGFR4 expression was inconsistent in the bovine CL. The present data indicate that FGFR1 and FGFR2 splice variants are the main receptors for FGF action in the bovine CL.

Impaired FGF signaling contributes to cleft lip and palate.

Nonsyndromic cleft lip and palate (NS CLP) is a complex birth defect resulting from a combination of genetic and environmental factors. Several members of the FGF and FGFR families are expressed during craniofacial development and can rarely harbor mutations that result in human clefting syndromes. We hypothesized that disruptions in this pathway might also contribute to NS CLP. We sequenced the coding regions and performed association testing on 12 genes (FGFR1, FGFR2, FGFR3, FGF2, FGF3, FGF4, FGF7, FGF8, FGF9, FGF10, FGF18, and NUDT6) and used protein structure analyses to predict the function of amino acid variants. Seven likely disease-causing mutations were identified, including: one nonsense mutation (R609X) in FGFR1, a de novo missense mutation (D73H) in FGF8, and other missense variants in FGFR1, FGFR2, and FGFR3. Structural analysis of FGFR1, FGFR2, and FGF8 variants suggests that these mutations would impair the function of the proteins, albeit through different mechanisms. Genotyping of SNPs in the genes found associations between NS CLP and SNPs in FGF3, FGF7, FGF10, FGF18, and FGFR1. The data suggest that the FGF signaling pathway may contribute to as much as 3-5% of NS CLP and will be a consideration in the clinical management of CLP.