scholarly journals Novel Mutations in Thiazide-Sensitive Na-Cl Cotransporter Gene of Patients with Gitelman's Syndrome

2000 ◽  
Vol 11 (1) ◽  
pp. 65-70
Author(s):  
TOSHIAKI MONKAWA ◽  
ISAO KURIHARA ◽  
KAZUO KOBAYASHI ◽  
MATSUHIKO HAYASHI ◽  
TAKAO SARUTA
Keyword(s):  
Missense Mutation ◽  
Direct Sequencing ◽  
Gene Mutations ◽  
Autosomal Recessive Disorder ◽  
Japanese Patients ◽  
Paternal Allele ◽  
Homozygous Mutation ◽  
Gitelman's Syndrome ◽  
Sequencing Method

Abstract. Gitelman's syndrome (GS) is an autosomal recessive disorder characterized by metabolic alkalosis, hypokalemia, hypomagnesemia, and hypocalciuria that has recently been reported to be linked to thiazide-sensitive Na-Cl cotransporter (TSC) gene mutations. In this study, possible mutations in the TSC gene of six Japanese patients clinically diagnosed with GS were investigated. Twenty-six exons encoding TSC were amplified by PCR and then completely sequenced by the direct sequencing method. Patient A showed a missense mutation of Arg 642 to Cys on the paternal allele and a missense mutation of Val 578 to Met and a 2-bp deletion (nucleotide 2543-2544) on the maternal allele. This deletion results in a frameshift that alters codon 837 to encode a stop signal rather than phenylalanine, and it is predicted to lead to loss of the latter half of the intracellular carboxy terminus. In the second family, two affected sisters, patients B and C, had a homozygous missense mutation of Thr 180 to Lys. Both of their parents, who are consanguineously married, have a heterozygous Thr180Lys mutation. Patient D has a homozygous mutation Thr180Lys, which is the same as the second family. Haplotype analysis indicates that patients B and C are not related to patient D. In patients E and F, we could identify only one mutant allele; Ala569Glu and Leu849His, respectively. All of the mutations identified are novel except for the Arg642Cys mutation, which has been found in a Japanese GS patient. Although further in vitro study is required to prove that the mutations are responsible for GS, it is possible that Thr180Lys and Arg642Cys mutations might be common mutations in Japanese GS.

scholarly journals Neonatal presentation of familial glucocorticoid deficiency resulting from a novel splice mutation in the melanocortin 2 receptor accessory protein

2011 ◽  
Vol 165 (6) ◽  
pp. 987-991 ◽  
Author(s):  
V Jain ◽  
L A Metherell ◽  
A David ◽  
R Sharma ◽  
P K Sharma ◽  
...  
Keyword(s):  
Transmembrane Domain ◽  
Novel Mutation ◽  
Direct Sequencing ◽  
Autosomal Recessive Disorder ◽  
Normal Male ◽  
Accessory Protein ◽  
Homozygous Mutation ◽  
Early Presentation ◽  
Glucocorticoid Deficiency

BackgroundFamilial glucocorticoid deficiency (FGD) is a rare autosomal recessive disorder characterised by isolated glucocorticoid deficiency. Mutations in the ACTH receptor/melanocortin 2 receptor (MC2R), the MC2R accessory protein (MRAP) or the STAR protein (STAR) cause FGD types 1, 2 and 3, respectively, accounting for ∼50% of all cases.Patient and methodsWe report a neonate of Indian origin, who was diagnosed with FGD in the first few days of life. He presented with hypoglycaemic seizures and was noted to have generalised intense hyperpigmentation and normal male genitalia. Biochemical investigations revealed hypocortisolaemia (cortisol 0.223 μg/dl; NR 1–23 μg/dl) and elevated plasma ACTH (170 pg/ml). Serum electrolytes, aldosterone and plasma renin activity were normal. Peak cortisol following a standard synacthen test was 0.018 μg/dl. He responded to hydrocortisone treatment and continues on replacement. Patient DNA was analysed by direct sequencing. The effect of the novel mutation was assessed by an in vitro splicing assay using wild type and mutant heterologous minigenes.ResultsA novel homozygous mutation c.106+2_3dupTA was found in the MRAP gene. Both parents were heterozygous for the mutation. In an in vitro splicing assay, the mutation resulted in the skipping of exon 3.ConclusionWe have identified a novel MRAP mutation where disruption of the intron 3 splice-site results in a prematurely terminated translation product. This protein (if produced) would lack the transmembrane domain that is essential for MC2R interaction. We predict that this would cause complete lack of ACTH response thus explaining the early presentation in this case.

A Novel Mutation Glyl672→Arg in Type 2A and a Homozygous Mutation in Type 2B von Willebrand Disease

1996 ◽  
Vol 76 (02) ◽  
pp. 253-257 ◽  
Author(s):  
Takeshi Hagiwara ◽  
Hiroshi Inaba ◽  
Shinichi Yoshida ◽  
Keiko Nagaizumi ◽  
Morio Arai ◽  
...  
Keyword(s):  
Missense Mutation ◽  
Novel Mutation ◽  
Point Mutations ◽  
Japanese Patients ◽  
Von Willebrand Disease ◽  
Homozygous Mutation ◽  
Missense Mutations ◽  
Reaction Products ◽  
Type 3 ◽  
Von Willebrand

SummaryGenetic materials from 16 unrelated Japanese patients with von Willebrand disease (vWD) were analyzed for mutations. Exon 28 of the von Willebrand factor (vWF) gene, where point mutations have been found most frequent, was screened by various restriction-enzyme analyses. Six patients were observed to have abnormal restriction patterns. By sequence analyses of the polymerase chain-reaction products, we identified a homozygous R1308C missense mutation in a patient with type 2B vWD; R1597W, R1597Q, G1609R and G1672R missense mutations in five patients with type 2A; and a G1659ter nonsense mutation in a patient with type 3 vWD. The G1672R was a novel missense mutation of the carboxyl-terminal end of the A2 domain. In addition, we detected an A/C polymorphism at nucleotide 4915 with HaeIII. There was no particular linkage disequilibrium of the A/C polymorphism, either with the G/A polymorphism at nucleotide 4391 detected with Hphl or with the C/T at 4891 detected with BstEll.

scholarly journals Detected EGFR mutation in cerebrospinal fluid of lung adenocarcinoma patients with meningeal metastasis

Open Medicine ◽  
2016 ◽  
Vol 11 (1) ◽  
pp. 93-96 ◽  
Author(s):  
Jiang Rong ◽  
Ma Chunhua ◽  
Lv Yuan ◽  
Mu Ning ◽  
Li Jinduo ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Lung Adenocarcinoma ◽  
Gene Mutation ◽  
Direct Sequencing ◽  
Gene Mutations ◽  
Egfr Mutations ◽  
Egfr Gene ◽  
Sequencing Method ◽  
Direct Sequencing Method ◽  
Egfr Gene Mutation

AbstractObjectiveTo discuss the application of ARMS method to detect EGFR gene mutation in cerebrospinal fluid of lung adenocarcinoma patients with meningeal metastasis.Methods5 cases of lung adenocarcinoma were identified with meningeal metastasis that were cleared EGFR gene mutation by gene sequencing method. From each patient 5ml cerebrospinal fluid was obtained by lumbar puncture. ARMS method was used to detect EGFR mutations in cerebrospinal fluid.Results5 samples of cerebrospinal fluid were successfully detected by ARMS method, 3 samples found that EGFR gene mutations, the mutations in line with direct sequencing method.ConclusionARMS method can be used to detect EGFR gene mutations of cerebrospinal fluid samples in lung adenocarcinoma with meningeal metastasis. But cerebrospinal fluid specimens from histological specimens, blood samples need to be confirmed by further comparative study whether there is advantage.

scholarly journals Vitamin D 1α-Hydroxylase Gene Mutations in Patients with 1α-Hydroxylase Deficiency

2007 ◽  
Vol 92 (8) ◽  
pp. 3177-3182 ◽  
Author(s):  
Chan Jong Kim ◽  
Larry E. Kaplan ◽  
Farzana Perwad ◽  
Ningwu Huang ◽  
Amita Sharma ◽  
...  
Keyword(s):  
Vitamin D ◽  
Direct Sequencing ◽  
Gene Mutations ◽  
Splice Site Mutation ◽  
Autosomal Recessive Disorder ◽  
The United States ◽  
Site Mutation ◽  
Hydroxylase Deficiency ◽  
Exon 2 ◽  
Hydroxylase Gene

Abstract Context: Vitamin D 1α-hydroxylase deficiency, also known as vitamin D-dependent rickets type 1, is an autosomal recessive disorder characterized by the early onset of rickets with hypocalcemia and is caused by mutations of the 25-hydroxyvitamin D 1α-hydroxylase (1α-hydroxylase, CYP27B1) gene. The human gene encoding the 1α-hydroxylase is 5 kb in length, located on chromosome 12, and comprises nine exons and eight introns. We previously isolated the human 1α-hydroxylase cDNA and gene and identified 19 different mutations in 25 patients with 1α-hydroxylase deficiency. Objectives, Patients, and Methods: We analyzed the 1α-hydroxylase gene of 10 patients, five from Korea, two from the United States, and one each from Argentina, Denmark, and Morocco, all from nonconsanguineous families. Each had clinical and radiographic features of rickets, hypocalcemia, and low serum concentrations of 1,25-dihydroxyvitamin D3. Results: Direct sequencing identified the responsible 1α-hydroxylase gene mutations in 19 of 20 alleles. Four novel and four known mutations were identified. The new mutations included a nonsense mutation in exon 6, substitution of adenine for guanine (2561G→A) creating a stop signal at codon 328; deletion of adenine in exon 9 (3922delA) causing a frameshift; substitution of thymine for cytosine in exon 2 (1031C→T) causing the amino acid change P112L; and a splice site mutation, substitution of adenine for guanine in the first nucleotide of intron 7 (IVS7+1 G→A) causing a frameshift. Conclusions: Mutations in the 1α-hydroxylase gene previously were identified in 44 patients, to which we add 10 more. The studies show a strong correlation between 1α-hydroxylase mutations and the clinical findings of 1α-hydroxylase deficiency.

scholarly journals SAMHD1Gene Mutations Are Associated with Cerebral Large-Artery Atherosclerosis

2015 ◽  
Vol 2015 ◽  
pp. 1-8
Author(s):  
Wei Li ◽  
Baozhong Xin ◽  
Junpeng Yan ◽  
Ying Wu ◽  
Bo Hu ◽  
...  
Keyword(s):  
Small Vessel Disease ◽  
Direct Sequencing ◽  
Gene Mutations ◽  
Splice Site Mutation ◽  
Large Artery ◽  
Missense Mutations ◽  
Site Mutation ◽  
Chinese Han ◽  
Functionally Impaired

Background. To investigate whether one or moreSAMHD1gene mutations are associated with cerebrovascular disease in the general population using a Chinese stroke cohort.Methods. Patients with a Chinese Han background (N=300) diagnosed with either cerebral large-artery atherosclerosis (LAA,n=100), cerebral small vessel disease (SVD,n=100), or other stroke-free neurological disorders (control,n=100) were recruited. Genomic DNA from the whole blood of each patient was isolated, and direct sequencing of theSAMHD1gene was performed. Both wild type and mutant SAMHD1 proteins identified from the patients were expressed inE. coliand purified; then their dNTPase activities and ability to form stable tetramers were analysedin vitro.Results. Three heterozygous mutations, including two missense mutations c.64C>T (P22S) and c.841G>A (p.E281K) and one splice site mutation c.696+2T>A, were identified in the LAA group with a prevalence of 3%. No mutations were found in the patients with SVD or the controls (p=0.05). The mutant SAMHD1 proteins were functionally impaired in terms of their catalytic activity as a dNTPase and ability to assemble stable tetramers.Conclusions. HeterozygousSAMHD1gene mutations might cause genetic predispositions that interact with other risk factors, resulting in increased vulnerability to stroke.

Exome sequencing and functional studies in zebrafish identify WDR8 as the causative gene for isolated Microspherophakia in Indian families

2021 ◽  
Author(s):  
M Madhangi ◽  
Debanjan Dutta ◽  
Sautan Show ◽  
Vishwanath K Bhat ◽  
Mohammad I Rather ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Exome Sequencing ◽  
Missense Mutation ◽  
Protein Function ◽  
Homozygosity Mapping ◽  
Spindle Pole ◽  
Homozygous Mutation ◽  
Spherical Lens ◽  
Causative Gene

Abstract Isolated Microspherophakia (MSP) is an autosomal recessive disorder characterized by a smaller than normal spherical lens. Till date, LTBP2 is the only gene shown to cause MSP. We used homozygosity mapping and whole-exome sequencing and identified a homozygous mutation, c.1148C > T (p.Pro383Leu), in the WDR8 (or WRAP73) gene in two Indian MSP families. In vitro experiments showed that the missense mutation renders the protein unstable. WDR8 is a centriolar protein that has important roles in centrosomal assembly, spindle pole formation and ciliogenesis. Co-immunoprecipitation experiments from HeLa cells indicated that the mutation interferes with the interaction of WDR8 with its binding partners. In zebrafish, both morpholino-mediated knockdown and CRISPR/Cas knockout of wdr8 resulted in decreased eye and lens size. The lack of wdr8 affected cell cycle progression in the retinal cells, causing a reduction in cell numbers in the retina and lens. The reduction in eye size and the cell cycle defects were rescued by exogenous expression of the human wild-type WDR8. However, the human mutant WDR8 (p.Pro383Leu) was unable to rescue the eye defects, indicating that the missense mutation abrogates WDR8 protein function. Thus, our zebrafish results suggested that WDR8 is the causative gene for MSP in these Indian families.

scholarly journals Pyrazinamide resistance associated with pncA gene mutation in Mycobacterium tuberculosis in Japan

2002 ◽  
Vol 128 (2) ◽  
pp. 337-342 ◽  
Author(s):  
T. ENDOH ◽  
A. YAGIHASHI ◽  
N. UEHARA ◽  
D. KOBAYASHI ◽  
N. TSUJI ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Direct Sequencing ◽  
Gene Mutations ◽  
Japanese Patients ◽  
Wild Type ◽  
Gene Encoding ◽  
Single Strand Conformational Polymorphism ◽  
Proportion Method ◽  
Polymerase Chain ◽  
Medium Method

Thirty Japanese clinical isolates of Mycobacterium tuberculosis were analysed by pyrazinamide susceptibility testing and pyrazinamidase assay, as well as polymerase chain reaction for single-strand conformational polymorphism and direct sequencing of the gene encoding pyrazinamidase (pncA). All sensitive isolates showed pyrazinamidase activity and a wild-type pncA gene, but three resistant isolates had pncA gene mutations and lacked pyrazinamidase activity. The latter isolates showed a minimum inhibitory concentration of at least 100 mg/l by the 7H10 agar proportion method and 400 mg/l by the 7H9 liquid medium method. Isolate 28 showed T-to-C change at position 11, leading to Leu4→Ser substitution; isolate 29 had an 8-bp deletion from position 382; and isolate 30 had A-to-C change at position 29, leading to Gln10→Pro substitution. The deletion has not been described previously. This is the first demonstration of pncA gene mutations in PZA-resistant M. tuberculosis strains isolated from Japanese patients.

A New Candidate Missense Mutation (Leu 1657 Ile) in an Apparently Asymptomatic Type 2A (Phenotype IIA) von Willebrand Disease Family

2000 ◽  
Vol 84 (09) ◽  
pp. 369-373 ◽  
Author(s):  
A. M. Guilliatt ◽  
G. K. Surdhar ◽  
B. D. M. Theophilus ◽  
F. G. H. Hill ◽  
M. S. Enayat
Keyword(s):  
Missense Mutation ◽  
Direct Sequencing ◽  
Mutation Screening ◽  
Von Willebrand Disease ◽  
Site Directed Mutagenesis ◽  
Enzyme Analysis ◽  
Restriction Enzyme Analysis ◽  
Full Spectrum ◽  
Von Willebrand

SummaryType 2A von Willebrand disease (VWD) is mostly an autosomal dominantly inherited bleeding disorder characterised by a qualitative defect of von Willebrand factor (VWF). Mutation screening was used to screen the whole of VWF gene followed by direct sequencing to detect the mutation in a father and son diagnosed with type 2A (phenotype IIA) von Willebrand disease. A C5219 to A transversion was detected predicting Leucine to Isoleucine substitution in codon 1657. This novel missense mutation which was also identified by MboI restriction enzyme analysis, was found in both patient and his father but not in any other unaffected family member or 50 unrelated normal individuals. This substitution was reproduced by in vitro site directed mutagenesis of full-length VWF cDNA and transiently expressed in COS-7 cells. The corresponding recombinant VWF protein exhibited the full spectrum of VWF multimers, suggesting that the abnormal multimer seen in the patient results from increased proteolysis.

scholarly journals Novel Mutations of the Chloride Channel Kb Gene in Two Japanese Patients Clinically Diagnosed as Bartter Syndrome with Hypocalciuria

2004 ◽  
Vol 89 (11) ◽  
pp. 5847-5850 ◽  
Author(s):  
Shigeru Fukuyama ◽  
Misako Hiramatsu ◽  
Motohiro Akagi ◽  
Mutumi Higa ◽  
Takao Ohta
Keyword(s):  
Direct Sequencing ◽  
Japanese Patients ◽  
Bartter Syndrome ◽  
Calcium Handling ◽  
K Channel ◽  
Renal Tubular Cells ◽  
Sequencing Method ◽  
Renal Tubular ◽  
Intron 2 ◽  
Genotype Correlation

Abstract Hypokalemic metabolic tubulopathy, such as in Bartter syndrome and Gitelman syndrome, is caused by the dysfunction of renal electrolyte transporters. Despite advances in molecular genetics with regard to hypokalemic metabolic tubulopathy, recent reports have suggested that the phenotype-genotype correlation is still confusing, especially in classic Bartter and Gitelman syndromes. We report here two Japanese patients who suffered from clinically diagnosed classic Bartter syndrome but who presented hypocalciuria. Hypocalciuria is generally believed to be a pathognomonic finding of NCCT malfunction. To better understand the genotype-phenotype correlation in these two cases, we screened four renal electrolyte transporter genes [Na-K-2Cl cotransporter (NKCC2), renal outer medullary K channel (ROMK), Cl channel Kb (ClC-Kb), and Na-Cl cotransporter (NCCT)] by the PCR direct sequencing method. We identified three ClC-Kb allelic variants, including two new mutations (L27R and W610X in patient 1 and a G to C substitution of a 3′ splice site of intron 2 and W610X in patient 2). We did not find any mutations in the other three genes. Our present data suggest that some ClC-Kb mutations may affect calcium handling in renal tubular cells.

Congenital afibrinogenemia: identification and expression of a missense mutation in FGB impairing fibrinogen secretion

Blood ◽  
2003 ◽  
Vol 102 (13) ◽  
pp. 4413-4415 ◽  
Author(s):  
Dung Vu ◽  
Paula H. B. Bolton-Maggs ◽  
Jeremy R. Parr ◽  
Michael A. Morris ◽  
Philippe de Moerloose ◽  
...  
Keyword(s):  
Missense Mutation ◽  
Gene Mutations ◽  
Great Majority ◽  
Autosomal Recessive Disorder ◽  
Homozygous Deletion ◽  
Chain Gene ◽  
Missense Mutations ◽  
Exon 2 ◽  
Congenital Afibrinogenemia ◽  
The Media

Abstract Congenital afibrinogenemia is a rare autosomal recessive disorder characterized by complete absence of detectable fibrinogen. We previously identified the first causative mutations for this disease: a homozygous deletion of approximately 11 kb of the fibrinogen α-chain gene (FGA). Subsequent studies revealed that the great majority of afibrinogenemia mutations are localized in FGA, but mutations were also found in FGG and FGB. Apart from 3 missense mutations identified in the C-terminal portion of FGB, all fibrinogen gene mutations responsible for afibrinogenemia are null. In this study, a young boy with afibrinogenemia was found to be a compound heterozygote for 2 mutations in FGB: an N-terminal nonsense mutation W47X (exon 2) and a missense mutation (G444S, exon 8). Coexpression of the FGB G444S mutant cDNA in combination with wild-type FGA and FGG cDNAs demonstrated that fibrinogen molecules containing the mutant β chain are able to assemble but are not secreted into the media, confirming the pathogenic nature of the identified mutation. (Blood. 2003;102:4413-4415)

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