scholarly journals Diversity of ARSACS Mutations in French-Canadians

2013 ◽  
Vol 40 (1) ◽  
pp. 61-66 ◽  
Author(s):  
I. Thiffault ◽  
M.J. Dicaire ◽  
M. Tetreault ◽  
K.N. Huang ◽  
J. Demers-Lamarche ◽  
...  
Keyword(s):  
Low Cost ◽  
Phenotypic Variability ◽  
Mutation Screening ◽  
Gene Mutations ◽  
Genotypic Diversity ◽  
Loss Of Function ◽  
French Canadian ◽  
Spastic Ataxia ◽  
Large Gene ◽  
Canadian Population

Abstract:Background:The growing number of spastic ataxia of Charlevoix-Saguenay (SACS) gene mutations reported worldwide has broadened the clinical phenotype of autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS). The identification of Quebec ARSACS cases without two knownSACSmutation led to the development of a multi-modal genomic strategy to uncover mutations in this large gene and explore phenotype variability.Methods:Search forSACSmutations by combining various methods on 20 cases with a classical French-Canadian ARSACS phenotype without two mutations and a group of 104 sporadic or recessive spastic ataxia cases of unknown cause. Western blot on lymphoblast protein from cases with different genotypes was probed to establish if they still expressed sacsin.Results:A total of 12 mutations, including 7 novels, were uncovered in Quebec ARSACS cases. The screening of 104 spastic ataxia cases of unknown cause for 98SACSmutations did not uncover carriers of two mutations. Compounds heterozygotes for one missenseSACSmutation were found to minimally express sacsin.Conclusions:The large number ofSACSmutations present even in Quebec suggests that the size of the gene alone may explain the great genotypic diversity. This study does not support an expanding ARSACS phenotype in the French-Canadian population. Most mutations lead to loss of function, though phenotypic variability in other populations may reflect partial loss of function with preservation of some sacsin expression. Our results also highlight the challenge ofSACSmutation screening and the necessity to develop new generation sequencing methods to ensure low cost complete gene sequencing.

scholarly journals Genetics of Congenital Isolated TSH Deficiency: Mutation Screening of the Known Causative Genes and a Literature Review

2019 ◽  
Vol 104 (12) ◽  
pp. 6229-6237 ◽  
Author(s):  
Chiho Sugisawa ◽  
Tetsuya Takamizawa ◽  
Kiyomi Abe ◽  
Tomonobu Hasegawa ◽  
Kentaro Shiga ◽  
...  
Keyword(s):  
Literature Review ◽  
Single Gene ◽  
Mutation Screening ◽  
Gene Mutations ◽  
Serum Prolactin ◽  
Loss Of Function ◽  
Mutation Carriers ◽  
Tsh Levels ◽  
Tsh Deficiency

Abstract Context Congenital isolated TSH deficiency (i-TSHD) is a rare form of congenital hypothyroidism. Five genes (IGSF1, IRS4, TBL1X, TRHR, and TSHB) responsible for the disease have been identified, although their relative frequencies and hypothalamic/pituitary unit phenotypes have remained to be clarified. Objectives To define the relative frequencies and hypothalamic/pituitary unit phenotypes of congenital i-TSHD resulting from single gene mutations. Patients and Methods Thirteen Japanese patients (11 boys and 2 girls) with congenital i-TSHD were enrolled. IGSF1, IRS4, TBL1X, TRHR, and TSHB were sequenced. For a TBL1X mutation (p.Asn382del), its pathogenicity was verified in vitro. For a literature review, published clinical data derived from 74 patients with congenital i-TSHD resulting from single-gene mutations were retrieved and analyzed. Results Genetic screening of the 13 study subjects revealed six mutation-carrying patients (46%), including five hemizygous IGSF1 mutation carriers and one hemizygous TBL1X mutation carrier. Among the six mutation carriers, one had intellectual disability and the other one had obesity, but the remaining four did not show nonendocrine phenotypes. Loss of function of the TBL1X mutation (p.Asn382del) was confirmed in vitro. The literature review demonstrated etiology-specific relationship between serum prolactin (PRL) levels and TRH-stimulated TSH levels with some degree of overlap. Conclusions The mutation screening study covering the five causative genes of congenital i-TSHD was performed, showing that the IGSF1 defect was the leading genetic cause of the disease. Assessing relationships between serum PRL levels and TRH-stimulated TSH levels would contribute to predict the etiologies of congenital i-TSHD.

A Melanocortin-4 Receptor Agonist Induces Skin and Hair Pigmentation in Patients with Monogenic Mutations in the Leptin-Melanocortin Pathway

2021 ◽  
pp. 1-10
Author(s):  
Varvara Kanti ◽  
Lia Puder ◽  
Irina Jahnke ◽  
Philipp Maximilian Krabusch ◽  
Jan Kottner ◽  
...  
Keyword(s):  
Leptin Receptor ◽  
Skin Pigmentation ◽  
Gene Mutations ◽  
Continuous Treatment ◽  
Whole Body ◽  
Hair Color ◽  
Phase 2 ◽  
Loss Of Function ◽  
The Impact ◽  
Over Time

<b><i>Background and Objectives:</i></b> Gene mutations within the leptin-melanocortin signaling pathway lead to severe early-onset obesity. Recently, a phase 2 trial evaluated new pharmacological treatment options with the MC4R agonist <i>setmelanotide</i> in patients with mutations in the genes encoding proopiomelanocortin (POMC) and leptin receptor (LEPR). During treatment with <i>setmelanotide,</i> changes in skin pigmentation were observed, probably due to off-target effects on the closely related melanocortin 1 receptor (MC1R). Here, we describe in detail the findings of dermatological examinations and measurements of skin pigmentation during this treatment over time and discuss the impact of these changes on patient safety. <b><i>Methods:</i></b> In an investigator-initiated, phase 2, open-label pilot study, 2 patients with loss-of-function POMC gene mutations and 3 patients with loss-of-function variants in LEPR were treated with the MC4R agonist <i>setmelanotide</i>. Dermatological examination, dermoscopy, whole body photographic documentation, and spectrophotometric measurements were performed at screening visit and approximately every 3 months during the course of the study. <b><i>Results:</i></b> We report the results of a maximum treatment duration of 46 months. Skin pigmentation increased in all treated patients, as confirmed by spectrophotometry. During continuous treatment, the current results indicate that elevated tanning intensity levels may stabilize over time. Lips and nevi also darkened. In red-haired study participants, hair color changed to brown after initiation of <i>setmelanotide</i> treatment. <b><i>Discussion:</i></b> <i>Setmelanotide</i> treatment leads to skin tanning and occasionally hair color darkening in both POMC- and LEPR-deficient patients. No malignant skin changes were observed in the patients of this study. However, the results highlight the importance of regular skin examinations before and during MC4R agonist treatment.

scholarly journals Production, characterization, and cross-reactivity of a polyclonal antibody against Arabidopsis TARGET OF RAPAMYCIN

2019 ◽  
Vol 62 (1) ◽  
Author(s):  
Gyeong-Im Shin ◽  
Sun Young Moon ◽  
Song Yi Jeong ◽  
Myung Geun Ji ◽  
Joon-Yung Cha ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Cross Reactivity ◽  
Target Of Rapamycin ◽  
Loss Of Function ◽  
Anticancer Activities ◽  
Purification Method ◽  
E Coli ◽  
Related Family ◽  
Large Gene ◽  
Truncated Variants

AbstractTARGET OF RAPAMYCIN (TOR), a member of the phosphatidylinositol 3-kinase-related family of protein kinases, is encoded by a single, large gene and is evolutionarily conserved in all eukaryotes. TOR plays a role as a master regulator that integrates nutrient, energy, and stress signaling to orchestrate development. TOR was first identified in yeast mutant screens, as its mutants conferred resistance to rapamycin, an antibiotic with immunosuppressive and anticancer activities. In Arabidopsis thaliana, the loss-of-function tor mutant displays embryo lethality, but the precise mechanisms of TOR function are still unknown. Moreover, a lack of reliable molecular and biochemical assay tools limits our ability to explore TOR functions in plants. Here, we produced a polyclonal α-TOR antibody using two truncated variants of TOR (1–200 and 1113–1304 amino acids) as antigens because recombinant full-length TOR is challenging to express in Escherichia coli. Recombinant His-TOR1−200 and His-TOR1113−1304 proteins were individually expressed in E. coli, and a mixture of proteins (at a 1:1 ratio) was used for immunizing rabbits. Antiserum was purified by an antigen-specific purification method, and the purified polyclonal α-TOR antibody successfully detected endogenous TOR proteins in wild-type Arabidopsis and TOR orthologous in major crop plants, including tomato, maize, and alfalfa. Moreover, our α-TOR antibody is useful for coimmunoprecipitation assays. In summary, we generated a polyclonal α-TOR antibody that detects endogenous TOR in various plant species. Our antibody could be used in future studies to determine the precise molecular mechanisms of TOR, which has largely unknown multifunctional roles in plants.

scholarly journals Nanopore Targeted Sequencing for Rapid Gene Mutations Detection in Acute Myeloid Leukemia

Genes ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 1026 ◽  
Author(s):  
Cumbo ◽  
Minervini ◽  
Orsini ◽  
Anelli ◽  
Zagaria ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Low Cost ◽  
Gene Mutations ◽  
Predictive Biomarkers ◽  
Molecular Testing ◽  
Sequencing Analysis ◽  
Cebpa Mutations ◽  
Targeted Gene Sequencing ◽  
Acute Myeloid

Acute myeloid leukemia (AML) clinical settings cannot do without molecular testing to confirm or rule out predictive biomarkers for prognostic stratification, in order to initiate or withhold targeted therapy. Next generation sequencing offers the advantage of the simultaneous investigation of numerous genes, but these methods remain expensive and time consuming. In this context, we present a nanopore-based assay for rapid (24 h) sequencing of six genes (NPM1, FLT3, CEBPA, TP53, IDH1 and IDH2) that are recurrently mutated in AML. The study included 22 AML patients at diagnosis; all data were compared with the results of S5 sequencing, and discordant variants were validated by Sanger sequencing. Nanopore approach showed substantial advantages in terms of speed and low cost. Furthermore, the ability to generate long reads allows a more accurate detection of longer FLT3 internal tandem duplications and phasing double CEBPA mutations. In conclusion, we propose a cheap, rapid workflow that can potentially enable all basic molecular biology laboratories to perform detailed targeted gene sequencing analysis in AML patients, in order to define their prognosis and the appropriate treatment.

Assessment of the prevalence of the 985A>G MCAD mutation in the French-Canadian population using allele-specific PCR

2007 ◽  
Vol 71 (6) ◽  
pp. 569-575 ◽  
Author(s):  
S Giroux ◽  
A Dubé-Linteau ◽  
G Cardinal ◽  
Y Labelle ◽  
N Laflamme ◽  
...  
Keyword(s):  
French Canadian ◽  
Specific Pcr ◽  
Canadian Population ◽  
Allele Specific ◽  
Allele Specific Pcr

scholarly journals Mutation screening of the thyroid peroxidase gene in a cohort of 55 Portuguese patients with congenital hypothyroidism

2005 ◽  
Vol 152 (2) ◽  
pp. 193-198 ◽  
Author(s):  
Carina Rodrigues ◽  
Paula Jorge ◽  
José Pires Soares ◽  
Isaura Santos ◽  
Regina Salomão ◽  
...  
Keyword(s):  
Congenital Hypothyroidism ◽  
Mutation Screening ◽  
Gene Mutations ◽  
Human Thyroid ◽  
Thyroid Peroxidase ◽  
Molecular Testing ◽  
Missense Mutations ◽  
Human Thyroid Peroxidase ◽  
Iodide Organification Defect ◽  
Organification Defect

Objective: Defects in the human thyroid peroxidase (TPO) gene are reported to be one of the causes of congenital hypothyroidism (CH) due to a total iodide organification defect. The aim of the present study was to determine the nature and frequency of TPO gene mutations in patients with CH, characterised by elevated TSH levels and orthotopic thyroid gland, identified in the Portuguese National Neonatal Screening Programme. Subjects and methods: The sample comprised 55 patients, from 53 unrelated families, with follow-up in the endocrinology clinics of the treatment centres of Porto and Lisbon. Mutation screening in the TPO gene (exons 1–17) was performed by single-strand conformational analysis followed by sequencing of fragments with abnormal migration patterns. Results: Eight different mutations were detected in 13 patients (seven homozygotes and six compound heterozygotes). Novel mutations included three missense mutations, namely 391T > C (S131P), 1274A > G (N425S) and 2512T > A (C838S), as well as the predictable splice mutation 2748G > A (Q916Q/spl?). The undocumented polymorphism 180-47A > C was also detected. Conclusion: The results are in accordance with previous observations confirming the genetic heterogeneity of TPO defects. The proportion of patients in which the aetiology was determined justifies the implementation of this molecular testing in our CH patients with dyshormonogenesis.

scholarly journals Functional characterization of a loss-of-function mutant I324M of arginine vasopressin receptor 2 in X-linked nephrogenic diabetes insipidus

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lixia Wang ◽  
Weihong Guo ◽  
Chunyun Fang ◽  
Wenli Feng ◽  
Yumeng Huang ◽  
...  
Keyword(s):  
Diabetes Insipidus ◽  
Arginine Vasopressin ◽  
Nephrogenic Diabetes Insipidus ◽  
Functional Characterization ◽  
Gene Mutations ◽  
Biochemical Properties ◽  
Vasopressin Receptor ◽  
Inherited Disease ◽  
Loss Of Function ◽  
Gene Encoding

AbstractX-linked nephrogenic diabetes insipidus (X-linked NDI) is a rare inherited disease mainly caused by lost-of-function mutations in human AVPR2 gene encoding arginine vasopressin receptor 2 (V2R). Our focus of the current study is on exploration of the functional and biochemical properties of Ile324Met (I324M) mutation identified in a pedigree showing as typical recessive X-linked NDI. We demonstrated that I324M mutation interfered with the conformation of complex glycosylation of V2R. Moreover, almost all of the I324M-V2R failed to express on the cell surface due to being captured by the endoplasmic reticulum control system. We further examined the signaling activity of DDAVP-medicated cAMP and ERK1/2 pathways and the results revealed that the mutant receptor lost the ability in response to DDAVP stimulation contributed to the failure of accumulation of cAMP and phosphorylated ERK1/2. Based on the characteristics of molecular defects of I324M mutant, we selected two reagents (SR49059 and alvespimycin) to determine whether the functions of I324M-V2R can be restored and we found that both compounds can significantly “rescue” I324M mutation. Our findings may provide further insights for understanding the pathogenic mechanism of AVPR2 gene mutations and may offer some implications on development of promising treatments for patients with X-linked NDI.

The domino gene of Drosophila encodes novel members of the SWI2/SNF2 family of DNA-dependent ATPases, which contribute to the silencing of homeotic genes

Development ◽  
2001 ◽  
Vol 128 (8) ◽  
pp. 1429-1441 ◽  
Author(s):  
M.L. Ruhf ◽  
A. Braun ◽  
O. Papoulas ◽  
J.W. Tamkun ◽  
N. Randsholt ◽  
...  
Keyword(s):  
Polytene Chromosomes ◽  
Gene Mutations ◽  
Polycomb Group ◽  
Protein Isoforms ◽  
Homeotic Genes ◽  
Loss Of Function ◽  
Trithorax Group ◽  
A Subunit ◽  
The Common ◽  
Hematopoietic Disorders

The Drosophila domino gene has been isolated in a screen for mutations that cause hematopoietic disorders. Generation and analysis of loss-of-function domino alleles show that the phenotypes are typical for proliferation gene mutations. Clonal analysis demonstrates that domino is necessary for cell viability and proliferation, as well as for oogenesis. domino encodes two protein isoforms of 3202 and 2498 amino acids, which contain a common N-terminal region but divergent C termini. The common region includes a 500 amino acid DNA-dependent ATPase domain of the SWI2/SNF2 family of proteins, which function via interaction with chromatin. We show that, although domino alleles do not exhibit homeotic phenotypes by themselves, domino mutations enhance Polycomb group mutations and counteract Trithorax group effects. The Domino proteins are present in large complexes in embryo extracts, and one isoform binds to a number of discrete sites on larval polytene chromosomes. Altogether, the data lead us to propose that domino acts as a repressor by interfering with chromatin structure. This activity is likely to be performed as a subunit of a chromatin-remodeling complex.

scholarly journals Biochemical Characterization of the GBA2 c.1780G>C Missense Mutation in Lymphoblastoid Cells from Patients with Spastic Ataxia

2018 ◽  
Vol 19 (10) ◽  
pp. 3099 ◽  
Author(s):  
Anna Malekkou ◽  
Maura Samarani ◽  
Anthi Drousiotou ◽  
Christina Votsi ◽  
Sandro Sonnino ◽  
...  
Keyword(s):  
Missense Mutation ◽  
Autosomal Recessive ◽  
Biochemical Characterization ◽  
Fold Increase ◽  
Loss Of Function ◽  
Spastic Paraplegia ◽  
Spastic Ataxia ◽  
Autosomal Recessive Cerebellar Ataxia ◽  
Compensatory Effect

The GBA2 gene encodes the non-lysosomal glucosylceramidase (NLGase), an enzyme that catalyzes the conversion of glucosylceramide (GlcCer) to ceramide and glucose. Mutations in GBA2 have been associated with the development of neurological disorders such as autosomal recessive cerebellar ataxia, hereditary spastic paraplegia, and Marinesco-Sjogren-Like Syndrome. Our group has previously identified the GBA2 c.1780G>C [p.Asp594His] missense mutation, in a Cypriot consanguineous family with spastic ataxia. In this study, we carried out a biochemical characterization of lymphoblastoid cell lines (LCLs) derived from three patients of this family. We found that the mutation strongly reduce NLGase activity both intracellularly and at the plasma membrane level. Additionally, we observed a two-fold increase of GlcCer content in LCLs derived from patients compared to controls, with the C16 lipid being the most abundant GlcCer species. Moreover, we showed that there is an apparent compensatory effect between NLGase and the lysosomal glucosylceramidase (GCase), since we found that the activity of GCase was three-fold higher in LCLs derived from patients compared to controls. We conclude that the c.1780G>C mutation results in NLGase loss of function with abolishment of the enzymatic activity and accumulation of GlcCer accompanied by a compensatory increase in GCase.

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