Generation of heterozygous (MCRIi030-A-1) and homozygous (MCRIi030-A-2) NR2F2/COUP-TFII knockout human iPSC lines.

The NR2F2 gene encodes the transcription factor COUP-TFII, which is upregulated in embryonic mesoderm. Heterozygous variants in NR2F2 cause a spectrum of congenital anomalies including cardiac and gonadal phenotypes. We generated heterozygous (MCRIi030-A-1) and homozygous (MCRIi030-A-2) NR2F2-knockout induced pluripotent stem cell (iPSC) lines from human fibroblasts using a one-step protocol for CRISPR/Cas9 gene-editing and episomal-based reprogramming. Both iPSC lines exhibited a normal karyotype, typical pluripotent cell morphology, pluripotency marker expression, and the capacity to differentiate into the three embryonic germ layers. These lines will allow us to explore the role of NR2F2 during development and disease.

RET 634 germline/gonadal mosaicism generating a second pathogenic amino acid change in multiple endocrine neoplasia type 2A.

Genetic testing for germline RET pathogenic variants, which cause the Multiple Endocrine Neoplasia Type 2 (MEN2) syndrome, has become crucial in managing patients with medullary thyroid carcinoma (MTC). Classically, RET heterozygous missense pathogenic variants are transmitted in a Mendelian autosomal dominant pattern, of which germline/gonadal mosaicism has never been reported. We report the novel occurrence of a MEN2A patient's family in which the siblings inherited three different RET 634 genotypes: wild type (p.Cys634), p.Cys634Gly or p.Cys634Arg heterozygous pathogenic variants. We hypothesized that germline/gonadal mosaicism, derived from an inherited + early somatic mutation in the mother or a double de novo mutation during maternal embryogenesis, led to this rare event in the RET gene. Exome analysis of the proband's deceased mother's paraffin-embedded thyroid tissue confirmed the three nucleotides in the same 634 codon position. For the first time, we describe germline/gonadal mosaicism in RET, generating a second pathogenic amino acid change in the same codon causing MEN2A. Our finding shows that RET parental mosaicism, confirmed by somatic exome sequencing, might explain discrepant genotype cases in siblings with inherited cancers.

COUP-TFII regulates early bipotential gonad signaling and commitment to ovarian progenitors.

BACKGROUND: The absence of expression of the Y-chromosome linked testis-determining gene SRY in early supporting gonadal cells (ESGC) leads bipotential gonads into ovarian development. However, genetic variants in NR2F2, encoding three isoforms of the transcription factor COUP-TFII, represent a novel cause of SRY-negative 46,XX testicular/ovotesticular differences of sex development (T/OT-DSD). Thus, we hypothesized that COUP-TFII is part of the ovarian developmental network. COUP-TFII is known to be expressed in interstitial/mesenchymal cells giving rise to steroidogenic cells in fetal gonads, however its expression and function in ESGCs have yet to be explored. RESULTS: By differentiating induced pluripotent stem cells into bipotential gonad-like cells in vitro and by analyzing single cell RNA-sequencing datasets of human fetal gonads, we identified that NR2F2 expression is highly upregulated during bipotential gonad development along with markers of bipotential state. NR2F2 expression was detected in early cell populations that precede the steroidogenic cell emergence and that retain a multipotent state in the undifferentiated gonad. The ESGCs differentiating into fetal Sertoli cells lost NR2F2 expression, whereas pre-granulosa cells remained NR2F2-positive. When examining the NR2F2 transcript variants individually, we demonstrated that the canonical isoform A, disrupted by frameshift variants previously reported in 46,XX T/OT-DSD patients, is nearly 1000-fold more highly expressed than other isoforms in bipotential gonad-like cells. To investigate the genetic network under COUP-TFII regulation in human gonadal cell context, we generated a NR2F2 knockout (KO) in the human granulosa-like cell line COV434 and studied NR2F2-KO COV434 cell transcriptome. NR2F2 ablation downregulated markers of ESGC and pre-granulosa cells. NR2F2-KO COV434 cells lost the enrichment for female-supporting gonadal progenitor and acquired gene signatures more similar to gonadal interstitial cells. CONCLUSIONS: Our findings suggest that COUP-TFII has a role in maintaining a multipotent state necessary for commitment to the ovarian development. We propose that COUP-TFII regulates cell fate during gonad development and impairment of its function may disrupt the transcriptional plasticity of ESGCs. During early gonad development, disruption of ESGC plasticity may drive them into commitment to the testicular pathway, as observed in 46,XX OT-DSD patients with NR2F2 haploinsufficiency.

Copy number variation in pituitary stalk interruption syndrome: A large case series of sporadic non-syndromic patients and literature review.

Abnormal hypothalamic/posterior pituitary development appears to be a major determinant of pituitary stalk interruption syndrome (PSIS). The observation of familial cases and associated congenital abnormalities suggests a genetic basis. Single-gene mutations explain less than 5% of the cases, and whole exome sequencing has shown heterogeneous results. The present study aimed to assess copy number variation (CNV) using array-based comparative genomic hybridization (aCGH) in patients with non-syndromic PSIS and comprehensively review data from the literature on CNV analysis in congenital hypopituitarism (CH) patients. Twenty-one patients with sporadic CH from our outpatient clinics presented with ectopic posterior pituitary (EPP) and no central nervous system abnormalities on magnetic resonance image (MRI) or any other malformations on physical examination at presentation were enrolled in the study. aCGH using a whole-genome customized 400K oligonucleotide platform was performed in our patients. For the literature review, we searched for case reports of patients with CH and CNV detected by either karyotype or aCGH reported in PubMed up to November 2021. Thirty-five distinct rare CNVs were observed in 18 patients (86%) and two of them (6%) were classified as pathogenic: one deletion of 1.8 Mb in chromosome 17 (17q12) and one deletion of 15 Mb in chromosome 18 (18p11.32p11.21), each one in a distinct patient. In the literature review, 67 pathogenic CNVs were published in 83 patients with CH, including the present study. Most of these patients had EPP (78% out of the 45 evaluated by sellar MRI) and were syndromic (70%). The most frequently affected chromosomes were X, 18, 20 and 1. Our study has found that CNV can be a mechanism of genetic abnormality in non-syndromic patients with CH and EPP. In future studies, one or more genes in those CNVs, both pathogenic and variant of uncertain significance, may be considered as good candidate genes.

Intelligence Quotient Variability in Klinefelter Syndrome Is Associated With GTPBP6 Expression Under Regulation of X-Chromosome Inactivation Pattern.

Klinefelter syndrome (KS) displays a broad dysmorphological, endocrinological, and neuropsychological clinical spectrum. We hypothesized that the neurocognitive dysfunction present in KS relies on an imbalance in X-chromosome gene expression. Thus, the X-chromosome inactivation (XCI) pattern and neurocognitive X-linked gene expression were tested and correlated with intelligence quotient (IQ) scores. We evaluated 11 KS patients by (a) IQ assessment, (b) analyzing the XCI patterns using both HUMARA and ZDHHC15 gene assays, and (c) blood RT-qPCR to investigate seven X-linked genes related to neurocognitive development (GTPBP6, EIF2S3, ITM2A, HUWE1, KDM5C, GDI1, and VAMP7) and XIST in comparison with 14 (male and female) controls. Considering IQ 80 as the standard minimum reference, we verified that the variability in IQ scores in KS patients seemed to be associated with the XCI pattern. Seven individuals in the KS group presented a random X-inactivation (RXI) and lower average IQ than the four individuals who presented a skewed X-inactivation (SXI) pattern. The evaluation of gene expression showed higher GTPBP6 expression in KS patients with RXI than in controls (p = 0.0059). Interestingly, the expression of GTPBP6 in KS patients with SXI did not differ from that observed in controls. Therefore, our data suggest for the first time that GTPBP6 expression is negatively associated with full-scale IQ under the regulation of the type of XCI pattern. The SXI pattern may regulate GTPBP6 expression, thereby dampening the impairment in cognitive performance and playing a role in intelligence variability in individuals with KS, which warrants further mechanistic investigations.

Spontaneous fertility and variable spectrum of reproductive phenotype in a family with adult-onset X-linked adrenal insufficiency harboring a novel DAX-1/NR0B1 mutation.

BACKGROUND: Adrenal hypoplasia congenita (AHC) is an X-linked disorder that affects the adrenal cortex and hypothalamus-pituitary-gonadal axis (HPG), leading to primary adrenocortical insufficiency (PAI) and hypogonadotropic hypogonadism. AHC is caused by a mutation in the DAX-1 gene (NR0B1). More commonly, this disease is characterized by early-onset PAI, with symptoms in the first months of life. However, a less severe phenotype termed late-onset AHC has been described, as PAI signs and symptoms may begin in adolescence and adulthood. Here we describe a family report of a novel mutation within NR0B1 gene and variable reproductive phenotypes, including spontaneous fertility, in a very late-onset X-linked AHC kindred. CASE PRESENTATION: Three affected maternal male relatives had confirmed PAI diagnosis between 30 y and at late 64 y. The X-linked pattern has made the endocrinology team to AHC suspicion. Regarding the HPG axis, all males presented a distinct degree of testosterone deficiency and fertility phenotypes, varying from a variable degree of hypogonadism, oligoasthenoteratozoospermia to spontaneous fertility. Interestingly, the other five maternal male relatives unexpectedly died during early adulthood, most likely due to undiagnosed PAI/adrenal crisis as the probable cause of their premature deaths. Sequencing analysis of the NR0B1 gene has shown a novel NR0B1 mutation (p.Tyr378Cys) that segregated in three AHC family members. CONCLUSIONS: NR0B1 p.Tyr378Cys segregates in an AHC family with a variable degree of adrenal and gonadal phenotypes, and its hemizygous trait explains the disease in affected family members. We recommend that NR0B1 mutation carriers, even those that are allegedly asymptomatic, be carefully monitored while reinforcing education to prevent PAI and consider early sperm banking when spermatogenesis still viable.

The Natural History of a Man With Ovotesticular 46,XX DSD Caused by a Novel 3-Mb 15q26.2 Deletion Containing NR2F2 Gene.

Gonadal sex determination is a complex genetic process by which an embryonic primordium is driven to form an ovary or a testis, which requires a delicate dosage balance involving many genes. Disruption in this molecular pathway can lead to differences of sex development (DSD). Although some genetic mechanisms leading to 46,XY DSD have been elucidated, little is known about copy-number variation (CNV) causing testicular or ovotesticular 46,XX DSD. We describe a 20-year natural history of a man with SRY-negative 46,XX who was born with atypical male external genitalia, aortic coarctation, and bilateral blepharophimosis-ptosis. The molecular study identified a de novo heterozygous 3-Mb 15q26.2 deletion, a gene-poor locus containing NR2F2, which encodes the nuclear receptor COUP-TFII that is highly expressed in ovary and cardiac arteries. Immunohistochemistry confirmed the low COUP-TFII expression on his ovotestis tissue. Monosomy of 15q26.2, encompassing the NR2F2 gene, may act as a Z-factor regulating the male sex determination negatively. This finding supports a novel type of CNV resulting in DSD in an individual who developed male puberty spontaneously.

Retroposed copies of RET gene: a somatically acquired event in medullary thyroid carcinoma.

BACKGROUND: Different pathogenic germline mutations in the RET oncogene are identified in MEN 2, a hereditary syndrome characterized by medullary thyroid carcinoma (MTC) and other endocrine tumors. Although genetic predisposition is recognized, not all RET mutation carriers will develop the disease during their lifetime or, likewise, RET mutation carriers belonging to the same family may present clinical heterogeneity. It has been suggested that a single germline mutation might not be sufficient for development of MEN 2-associated tumors and a somatic bi-allelic alteration might be required. Here we investigated the presence of somatic second hit mutation in the RET gene in MTC. METHODS: We integrated Multiplex Ligation-dependent Probe Amplification (MLPA) and whole exome sequencing (WES) to search for copy number alteration (CNA) in the RET gene in MTC samples and medullary thyroid cell lines (TT and MZ-CR-1). We next found reads spanning exon-exon boundaries on RET, an indicative of retrocopy. We subsequently searched for RET retrocopies in the human reference genome (GRCh37) and in the 1000 Genomes Project data, by looking for reads reporting joined exons in the RET locus or distinct genomic regions. To determine RET retrocopy specificity and recurrence, DNA isolated from sporadic and MEN 2-associated MTC (n = 37), peripheral blood (n = 3) and papillary thyroid carcinomas with RET fusion (n = 10) samples were tested using PCR-sequencing methodology. RESULTS: Through MLPA we have found evidence of CNA in the RET gene in MTC samples and MTC cell lines. WES analysis reinforced the presence of the CNA and hinted for a retroposed copy of RET not found in the human reference genome and 1.000 Genomes Project. Extended analysis confirmed the presence of a somatic MTC-related retrocopy of RET in both sporadic and hereditary tumors. We further unveiled a recurrent (28%) novel point mutation (p.G548 V) found exclusively in the retrocopy of RET. The mutation was also found in cDNA of mutated samples, suggesting it might be functional. CONCLUSION: We here report a somatic specific RET retroposed copy in MTC samples and cell lines. Our results support the idea that generation of retrocopies in somatic cells is likely to contribute to MTC genesis and progression.

Searching for mutations in the HNF1B gene in a Brazilian cohort with renal cysts and hyperglycemia

ABSTRACT Objective To verify the presence of variants in HNF1B in a sample of the Brazilian population selected according to the presence of renal cysts associated with hyperglycemia. Subjects and methods We evaluated 28 unrelated patients with clinical suspicion of HNF1B mutation because of the concomitant presence of diabetes mellitus (DM) or prediabetes and renal cysts. Genotyping was accomplished using Sanger sequencing or multiplex ligation-dependent probe amplification (MLPA). In positive cases, available relatives were recruited. Results We found two patients with HNF1B mutations. The first presented the variant p.Pro328Leufs*48(c.983delC) and had DM, renal cysts, and hypomagnesemia. The second presented a heterozygous whole gene deletion in HNF1B, DM, renal cysts, body and tail pancreatic agenesis, and hypomagnesemia; this alteration was also found in his two siblings and his father. Conclusion The recruitment of suspected cases of HNF1B gene mutations in Brazilians due to hyperglycemia and renal cysts presents two positive cases. Our cases contribute to the annotation of clinical and biochemical phenotypes of this rare form of maturity-onset diabetes of the young (MODY).

Cognitive and Psychiatric Evaluation in SYNE1 Ataxia.

SYNE1 gene mutations were identified as a cause of late-onset pure cerebellar syndrome. Non-cerebellar symptoms, including cognitive impairment, were already described in this condition. The aim of this study was to perform a detailed cognitive and psychiatric description of patients with SYNE1 gene mutations. We performed neuropsychological and psychiatric evaluations of six patients with SYNE1 ataxia and compared their performance with 18 normal controls paired for age and education level. SYNE1 ataxia patients present cognitive dysfunction, characterized by impairment in attention and processing speed domains. Otherwise, the psychiatric assessment reported low levels of overall behavioral symptoms with only some minor anxiety-related complaints. Although this is a small sample of patients, these results suggest that SYNE1 ataxia patients may represent a model to investigate effects of cerebellar degeneration in higher hierarchical cognitive functions. For further studies, abstract thinking impairment in schizophrenia may be related to dysfunction in cerebellum pathways.

Searching for mutations in the HNF1B gene in a Brazilian cohort with renal cysts and hyperglycemia.

OBJECTIVE: To verify the presence of variants in HNF1B in a sample of the Brazilian population selected according to the presence of renal cysts associated with hyperglycemia. SUBJECTS AND METHODS: We evaluated 28 unrelated patients with clinical suspicion of HNF1B mutation because of the concomitant presence of diabetes mellitus (DM) or prediabetes and renal cysts. Genotyping was accomplished using Sanger sequencing or multiplex ligation-dependent probe amplification (MLPA). In positive cases, available relatives were recruited. RESULTS: We found two patients with HNF1B mutations. The first presented the variant p.Pro328Leufs*48(c.983delC) and had DM, renal cysts, and hypomagnesemia. The second presented a heterozygous whole gene deletion in HNF1B, DM, renal cysts, body and tail pancreatic agenesis, and hypomagnesemia; this alteration was also found in his two siblings and his father. CONCLUSION: The recruitment of suspected cases of HNF1B gene mutations in Brazilians due to hyperglycemia and renal cysts presents two positive cases. Our cases contribute to the annotation of clinical and biochemical phenotypes of this rare form of maturity-onset diabetes of the young (MODY).

Genotype and phenotype landscape of MEN2 in 554 medullary thyroid cancer patients: the BrasMEN study.

Multiple endocrine neoplasia type 2 (MEN2) is an autosomal dominant genetic disease caused by RET gene germline mutations that is characterized by medullary thyroid carcinoma (MTC) associated with other endocrine tumors. Several reports have demonstrated that the RET mutation profile may vary according to the geographical area. In this study, we collected clinical and molecular data from 554 patients with surgically confirmed MTC from 176 families with MEN2 in 18 different Brazilian centers to compare the type and prevalence of RET mutations with those from other countries. The most frequent mutations, classified by the number of families affected, occur in codon 634, exon 11 (76 families), followed by codon 918, exon 16 (34 families: 26 with M918T and 8 with M918V) and codon 804, exon 14 (22 families: 15 with V804M and 7 with V804L). When compared with other major published series from Europe, there are several similarities and some differences. While the mutations in codons C618, C620, C630, E768 and S891 present a similar prevalence, some mutations have a lower prevalence in Brazil, and others are found mainly in Brazil (G533C and M918V). These results reflect the singular proportion of European, Amerindian and African ancestries in the Brazilian mosaic genome.

A pioneering RET genetic screening study in the State of Ceará, Brazil, evaluating patients with medullary thyroid cancer and at-risk relatives: experience with 247 individuals

ABSTRACT Objective: Initial diagnosis of medullary thyroid carcinoma (MTC) is frequently associated with advanced stages and a poor prognosis. Thus, the need for earlier diagnoses and detection in relatives at risk for the disease has led to increased use of RET genetic screening. Subjects and methods: We performed RET screening in 247 subjects who were referred to the Brazilian Research Consortium for Multiple Endocrine Neoplasia (BRASMEN) Center in the State of Ceará. Direct genetic sequencing was used to analyze exons 8, 10, 11, and 13-16 in MTC index cases and specific exons in at risk relatives. Afterward, clinical follow-up was offered to all the patients with MTC and their affected relatives. Results: RET screening was performed in 60 MTC index patients and 187 at-risk family members. At the initial clinical assessment of the index patients, 54 (90%) were diagnosed with apparently sporadic disease and 6 (10%) diagnosed with hereditary disease. After RET screening, we found that 31 (52%) index patients had sporadic disease, and 29 (48%) had hereditary disease. Regarding at-risk relatives, 73/187 were mutation carriers. Mutations in RET codon 804 and the rare p.M918V mutation were the most prevalent. Conclusions: Performing RET screening in Ceará allowed us to identify a different mutation profile in this region compared with other areas. RET screening also enabled the diagnosis of a significant number of hereditary MTC patients who were initially classified as sporadic disease patients and benefited their relatives, who were unaware of the risks and the consequences of bearing a RET mutation.

A novel GNRHR gene mutation causing congenital hypogonadotrophic hypogonadism in a Brazilian kindred.

Congenital hypogonadotrophic hypogonadism (CHH) is a challenging inherited endocrine disorder characterised by absent or incomplete pubertal development and infertility as a result of the low action/secretion of the hypothalamic gonadotrophin-releasing hormone (GnRH). Given a growing list of gene mutations accounting for CHH, the application of massively parallel sequencing comprises an excellent molecular diagnostic approach because it enables the simultaneous evaluation of many genes. The present study proposes the use of whole exome sequencing (WES) to identify causative and modifying mutations based on a phenotype-genotype CHH analysis using an in-house exome pipeline. Based on 44 known genes related to CHH in humans, we were able to identify a novel homozygous gonadotrophin-releasing hormone receptor (GNRHR) p.Thr269Met mutant, which segregates with the CHH kindred and was predicted to be deleterious by in silico analysis. A functional study measuring intracellular inositol phosphate (IP) when stimulated with GnRH on COS-7 cells confirmed that the p.Thr269Met GnRHR mutant performed greatly diminished IP accumulation relative to the transfected wild-type GnRHR. Additionally, the proband carries three heterozygous variants in CCDC141 and one homozygous in SEMA3A gene, although their effects with respect to modifying the phenotype are uncertain. Because they do not segregate with reproductive phenotype in family members, we advocate they do not contribute to CHH oligogenicity. WES proved to be useful for CHH molecular diagnosis and reinforced its benefit with respect to identifying heterogeneous genetic disorders. Our findings expand the GnRHR mutation spectrum and phenotype-genotype correlation in CHH.

Assessing the clinical and molecular diagnosis of inherited forms of impaired sensitivity to thyroid hormone from a single tertiary center.

AIM: Resistance to thyroid hormone (RTH), characterized by persistent hyperthyroxinemia with non-suppressed thyrotropin (TSH), is mostly caused by mutations in thyroid hormone receptor beta gene (THRB). Two differential diagnoses should be considered due to similar clinical and laboratory findings: TSH-producing pituitary adenoma (TPA) and Familial Dysalbuminemic Hyperthyroxinemia (FDH). The aim of this study is to describe our single tertiary center experience in the molecular diagnosis of RTH in Brazilian patients, analyzing their clinical and laboratory characteristics and the most common differential diagnosis. SUBJECTS AND METHODS: We enrolled 30 subjects with clinical and laboratory features of RTH. Patient´s evaluations included clinical examination, thyroid hormone profile and imaging tests. Sequencing analysis for THRB hot spot region was conducted on all patients, and those without mutations in beta isoform of the thyroid hormone receptor (TRß) (non-TR-RTH) were investigated for albumin gene (ALB) mutation. RESULTS: Seventeen patients presented mutations in TRß (RTHß); six were non-TR-RTH, three had a diagnosis of FDH with a mutation in ALB, and four were diagnosed with TPA. Two characteristics were different to what is commonly described in the literature: higher serum TSH levels in RTHß patients when compared to the non-TR-RTH group, but this difference did not extend to free T4 (FT4) level; also the percentage of non-TR-RTH was higher than what was reported in other series. CONCLUSION: In the present series, most cases were RTHß with higher levels of TSH. We described three novel mutations in THRB (p.M313V, p.R320G and p.R438P) and the first patients with FDH molecular diagnosis (p.R242H) documented in Brazil.

A pioneering RET genetic screening study in the State of Ceará, Brazil, evaluating patients with medullary thyroid cancer and at-risk relatives: experience with 247 individuals.

OBJECTIVE: Initial diagnosis of medullary thyroid carcinoma (MTC) is frequently associated with advanced stages and a poor prognosis. Thus, the need for earlier diagnoses and detection in relatives at risk for the disease has led to increased use of RET genetic screening. SUBJECTS AND METHODS: We performed RET screening in 247 subjects who were referred to the Brazilian Research Consortium for Multiple Endocrine Neoplasia (BRASMEN) Center in the State of Ceará. Direct genetic sequencing was used to analyze exons 8, 10, 11, and 13-16 in MTC index cases and specific exons in at risk relatives. Afterward, clinical follow-up was offered to all the patients with MTC and their affected relatives. RESULTS: RET screening was performed in 60 MTC index patients and 187 at-risk family members. At the initial clinical assessment of the index patients, 54 (90%) were diagnosed with apparently sporadic disease and 6 (10%) diagnosed with hereditary disease. After RET screening, we found that 31 (52%) index patients had sporadic disease, and 29 (48%) had hereditary disease. Regarding at-risk relatives, 73/187 were mutation carriers. Mutations in RET codon 804 and the rare p.M918V mutation were the most prevalent. CONCLUSIONS: Performing RET screening in Ceará allowed us to identify a different mutation profile in this region compared with other areas. RET screening also enabled the diagnosis of a significant number of hereditary MTC patients who were initially classified as sporadic disease patients and benefited their relatives, who were unaware of the risks and the consequences of bearing a RET mutation.

Novel lincRNA Susceptibility Gene and Its Role in Etiopathogenesis of Thyrotoxic Periodic Paralysis.

Thyrotoxic periodic paralysis (TPP) is a life-threatening neuromuscular complication of thyrotoxicosis characterized by muscle weakness and hypokalemia and with an unclear etiopathogenesis. However, the 17q24.3 locus had been genetically linked to TPP, in which the genetic variant rs312691 (TC genotype) in long intergenic noncoding RNA (lincRNA) CTD-2378E21.1 is located downstream of inward-rectifier potassium (Kir) channel genes [KCNJ2 and its antisense KCNJ2 (AS-KCNJ2)]. A TPP patient with a suppressed thyroid-stimulating hormone level, a high free thyroxine level of (5.8 ng/dL), and low serum potassium level of (2 mEq/L) was evaluated for Kir channel expression during and after recovery from thyrotoxicosis. We observed that circulating lincRNA and Kir expression varied in accordance with thyroid status and TC genotype. To endorse this association of a lincRNA-rs312691 variant with a genetic risk of TPP, an additional series of 37 patients with TPP and 32 patients with thyrotoxic without paralysis (TWP) were assessed. We verified that the risk of minor allele C was greater in TPP than in TWP (odds ratio, 5.289; P = 0.0062), and protective major allele T was more frequent than observed in the 1000 genome controls (odds ratio, 11.90; P < 0.0001). AS-KCNJ2 was downregulated during thyrotoxicosis in the TWP controls carrying allele T and were upregulated in those with TPP with risk allele C. Moreover, KCNJ2 (Kir2.1) expression was reduced during thyrotoxicosis and restored in euthyroid status. We further excluded any other coding variant by performing targeted exome sequencing mutational screening in 17q24.3. Our data suggest that high lincRNA AS-KCNJ2 and CDT-2378E21.1 expression, possibly driven by the triiodothyronine regulatory mechanism, reduces the Kir2.1 expression observed during thyrotoxicosis. This finding could contribute to the understanding of the reduced inward-rectifying current observed during muscle weakness in genetically susceptible TPP patients.

More than kin, less than kind: one family and the many faces of diabetes in youth

SUMMARY Identification of the correct etiology of diabetes brings important implications for clinical management. In this report, we describe a case of a 4-year old asymptomatic girl with diabetes since age 2, along with several individuals in her family with different etiologies for hyperglycemia identified in youth. Genetic analyses were made by Sanger sequencing, laboratory measurements included HbA1c, lipid profile, fasting C-peptide, pancreatic auto-antibodies (glutamic acid decarboxylase [GAD], Islet Antigen 2 [IA-2], and anti-insulin). We found a Gly178Ala substitution in exon 5 of GCK gene in three individuals co-segregating with diabetes, and type 1 diabetes was identified in two other individuals based on clinical and laboratory data. One individual with previous gestational diabetes and other with prediabetes were also described. We discuss difficulties in defining etiology of hyperglycemia in youth in clinical practice, especially monogenic forms of diabetes, in spite of the availability of several genetic, laboratory, and clinical tools.

Novel immunoassay for TSH measurement in rats.

Measuring thyroid hormones is an important aspect for the study of metabolism and for monitoring diseases in both human and animal models. The traditional method for hormone measurement in rats is the radioimmunoassay (RIA). However, the RIA is associated with some practical disadvantages, including the use of radioactive material, the need for specialized equipment and expert staff, the short shelf-life of kits according to the half-life of the radioisotope and high costs. The objective of this study was to develop a new cost-effective method for measuring TSH levels in rats that avoids the use of radioactive material. We developed an in-house competitive immunoassay using a reference standard, polyclonal antibody produced in rabbits and biotinylated antigen. This method was tested in 64 Wistar rats that were divided into a control group (n = 41) and a group with hypothyroidism (n = 23). Our assay demonstrated an analytical sensitivity of 0.24 ng/mL (n = 12) and an intra-assay coefficient of variation (CV) of 8.9% for sera with TSH levels of 1.5 ng/mL and 13.2% for sera with TSH levels of 17.5 ng/mL (n = 14). The inter-assay CV was 13.5% for sera with TSH levels of 1.4 ng/mL and 14.5% for TSH levels of 18.2 ng/mL (n = 5). The analysis of mean TSH levels in control rats (5.06 ± 0.5701) and hypothyroid rats (51.09 ± 5.136) revealed a statistically significant difference (p < 0.001) between the groups. This method showed good sensitivity, can be automated and is low-cost compared with RIA. Our method offers a viable alternative for TSH measurement in rats.

Novel immunoassay for TSH measurement in rats

ABSTRACT Measuring thyroid hormones is an important aspect for the study of metabolism and for monitoring diseases in both human and animal models. The traditional method for hormone measurement in rats is the radioimmunoassay (RIA). However, the RIA is associated with some practical disadvantages, including the use of radioactive material, the need for specialized equipment and expert staff, the short shelf-life of kits according to the half-life of the radioisotope and high costs. The objective of this study was to develop a new cost-effective method for measuring TSH levels in rats that avoids the use of radioactive material. We developed an in-house competitive immunoassay using a reference standard, polyclonal antibody produced in rabbits and biotinylated antigen. This method was tested in 64 Wistar rats that were divided into a control group (n = 41) and a group with hypothyroidism (n = 23). Our assay demonstrated an analytical sensitivity of 0.24 ng/mL (n = 12) and an intra-assay coefficient of variation (CV) of 8.9% for sera with TSH levels of 1.5 ng/mL and 13.2% for sera with TSH levels of 17.5 ng/mL (n = 14). The inter-assay CV was 13.5% for sera with TSH levels of 1.4 ng/mL and 14.5% for TSH levels of 18.2 ng/mL (n = 5). The analysis of mean TSH levels in control rats (5.06 ± 0.5701) and hypothyroid rats (51.09 ± 5.136) revealed a statistically significant difference (p < 0.001) between the groups. This method showed good sensitivity, can be automated and is low-cost compared with RIA. Our method offers a viable alternative for TSH measurement in rats.