Noval Mutation in Four Saudi Families with Glanzmann Thrombasthenia

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 1136-1136
Author(s):  
Tarek Owaidah ◽  
Hala Abalkhail ◽  
Abdulrahman Al Musa ◽  
Hasan Mosmali ◽  
Albanyan Abdulmajeed ◽  
...  
Keyword(s):  
Conflicts Of Interest ◽  
Stop Codon ◽  
Direct Sequencing ◽  
Family Members ◽  
Premature Stop Codon ◽  
Type I ◽  
Bleeding Tendency ◽  
Coding Region ◽  
Glanzmann Thrombasthenia ◽  
Exon 1

Abstract Abstract 1136 Introduction: Glanzmann thrombasthenia (GT) is a rare autosomal recessive inherited bleeding disorder characterized by an impaired platelet aggregation and variable bleeding tendency. Inherited genetic mutations in integrin alpha IIb and beta3 (ITGA2B, ITGB3) result in a heterogeneity of the thrombasthenia phenotypes. It is phenotypically expressed in homozygotes or compound heterozygotes, given that 50% of normal aIIbb3 is sufficient to guarantee unimpaired platelet function that result in asymptomatic carriers. Defects in ITGB3 result in failure of binding of B3 and alpha IIb. These defects had been reported in Arabs (Iraqi Jews). We are reporting some results of Saudi GT genotype project. Materials & Methods: In this study, we analyzed the entire coding region ITGB3 gene using polymerase chain reaction (PCR) and direct sequencing with primers specifically designed to amplify the coding region of exon 1–15 and exon /Intron boundaries in a cohort of 51 GT patients diagnosed and treated in our institute. Results: Out of 51 cases from 20 families had mutational screening of the ITGB3 gene with the aim to detect the causative pathogenic mutations to enable the pre-symptomatic diagnosis in at risk family members. In this study we detect 1 novel germline mutation c.2190delC (p.Ser703fs) in exon 13. The mutation is predicted to result in premature stop codon and protein truncation. The mutation was detected in 6 patients in homozygous stat (3 males and 3 females). Three tested samples from the patients family members detected the mutation in heterozygous state and all of them were asymptomatic with normal PFA and Intact expression of Platelet Glycoprotiens CD41(Gpllb), CD42a(GPIX), CD42b(GPlb), and CD61(Gpllla). All the GT patients with this mutation were type I GT with Prolonged PFA and complete absence of CD41(Gpllb) and CD61(Gpllla) glycoprotein. Conclusion: The result of this study represents the first Molecular analysis of ITGB3 gene in Saudi Arabia and displays the existence of novel pathogenic and possibly a founder effect in Saudi families. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Adrenocorticotropin-Dependent Precocious Puberty of Testicular Origin in a Boy with X-Linked Adrenal Hypoplasia Congenita Due to a Novel Mutation in the DAX1 Gene

2001 ◽  
Vol 86 (9) ◽  
pp. 4068-4071 ◽  
Author(s):  
Sorahia Domenice ◽  
Ana Claudia Latronico ◽  
Vinicius Nahime Brito ◽  
Ivo Jorge Prado Arnhold ◽  
Fernando Kok ◽  
...  
Keyword(s):  
Adrenal Insufficiency ◽  
Precocious Puberty ◽  
Stop Codon ◽  
Novel Mutation ◽  
Direct Sequencing ◽  
Receptor Gene ◽  
Premature Stop Codon ◽  
Rare Condition ◽  
Coding Region ◽  
Primary Adrenal Insufficiency

Primary adrenal insufficiency is a rare condition in pediatric age, and its association with precocious sexual development is very uncommon. We report a 2-yr-old Brazilian boy with DAX1 gene mutation whose first clinical manifestation was isosexual gonadotropin-independent precocious puberty. He presented with pubic hair, enlarged penis and testes, and advanced bone age. T levels were elevated, whereas basal and GnRH-stimulated LH levels were compatible with a prepubertal pattern. Chronic GnRH agonist therapy did not reduce T levels, supporting the diagnosis of gonadotropin-independent precocious puberty. Testotoxicosis was ruled out after normal sequencing of exon 11 of the LH receptor gene. At age 3 yr he developed clinical and hormonal features of severe primary adrenal insufficiency. The entire coding region of the DAX1 gene was analyzed through direct sequencing. A nucleotide G insertion between nucleotides 430 and 431 in exon 1, resulting in a novel frameshift mutation and a premature stop codon at position 71 of DAX-1, was identified. Surprisingly, steroid replacement therapy induced a clear decrease in testicular size and T levels to the prepubertal range. These findings suggest that chronic excessive ACTH levels resulting from adrenal insufficiency may stimulate Leydig cells and lead to gonadotropin-independent precocious puberty in some boys with DAX1 gene mutations.

scholarly journals Complete Androgen Insensitivity Caused by a New Frameshift Deletion of Two Base Pairs in Exon 1 of the Human Androgen Receptor Gene1

1999 ◽  
Vol 84 (5) ◽  
pp. 1751-1753 ◽  
Author(s):  
Brigitta Thiele ◽  
Wolfgang Weidemann ◽  
Doris Schnabel ◽  
Gabriela Romalo ◽  
Hans-Udo Schweikert ◽  
...  
Keyword(s):  
Androgen Receptor ◽  
Stop Codon ◽  
Novel Mutation ◽  
Reductase Activity ◽  
Receptor Gene ◽  
Premature Stop Codon ◽  
Androgen Receptor Gene ◽  
Coding Region ◽  
Androgen Insensitivity ◽  
Exon 1

We describe a novel mutation in exon 1 of the androgen receptor gene in a patient with complete androgen insensitivity (CAIS). Endocrine findings were typical for androgen insensitivity (testosterone serum levels in the upper limit of normal males and increased LH serum concentrations). Biochemical investigations in cultured genital skin fibroblasts of the patient showed a normal 5α-reductase activity but a complete absence of androgen binding. Western blot analysis revealed no detectable protein product. Sequence analysis of the entire coding region of the androgen receptor gene resulted in the identification of a 2-bp deletion in codon 472, causing frameshift and introduction of a premature stop codon 27 codons downstream of the mutation.

scholarly journals Type I Glanzmann thrombasthenia caused by an apparently silent β3 mutation that results in aberrant splicing and reduced β3 mRNA

2005 ◽  
Vol 93 (05) ◽  
pp. 897-903 ◽  
Author(s):  
Jingli Xie ◽  
Dina Pabón ◽  
Asier Jayo ◽  
Nora Butta ◽  
Consuelo González-Manchón
Keyword(s):  
Genomic Dna ◽  
Stop Codon ◽  
Genetic Defect ◽  
Premature Stop Codon ◽  
Splice Donor Site ◽  
Type I ◽  
Glanzmann Thrombasthenia ◽  
Base Pair Deletion ◽  
Mutant Transcript ◽  
Exon 11

SummaryWe report a novel genetic defect in a patient with type I Glanzmann thrombasthenia. Flow cytometry analysis revealed undetectable levels of platelet glycoproteins αIIb and β3, although residual amounts of both proteins were detectable in immunoblotting analysis. Sequence analysis of reversely transcribed platelet β3 mRNA showed a 100-base pair deletion in the 3’-boundary of exon 11, that results in a frame shift and appearance of a premature STOP codon. Analysis of the corresponding genomic DNA fragment revealed the presence of a homozygous C1815T transition in exon 11. The mutation does not change the amino acid residue but it creates an ectopic consensus splice donor site that is used preferentially, causing splicing out of part of exon 11. The parents of the proband, heterozygous for this mutation, were asymptomatic and had reduced platelet content of αIIbβ3. PCR-based relative quantification of β3 mRNA failed to detect the mutant transcript in the parents and showed a marked reduction in the patient. The results suggest that the thrombasthenic phenotype is, mainly, the result of the reduced availability of β3-mRNA, most probably due to activation of the nonsense-mediated mRNA decay mechanism. They also show the convenience of analyzing both genomic DNA and mRNA, in order to ascertain the functional consequences of single nucleotide substitutions.

A Sensitized Screen Uncovers a Novel Platelet Phenotype in a Loss-of-Function Jak2 Allele.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 2516-2516
Author(s):  
Nicole Anderson ◽  
Mojib Javadi Javed ◽  
Monica L Bailey ◽  
Kai Huang ◽  
Zorana Berberovic ◽  
...  
Keyword(s):  
Leptin Receptor ◽  
Conflicts Of Interest ◽  
Stop Codon ◽  
Premature Stop Codon ◽  
Protein Product ◽  
Causative Mutation ◽  
Mouse Strains ◽  
Loss Of Function ◽  
Coding Region ◽  
Exon 19

Abstract Abstract 2516 Poster Board II-493 Our group has undertaken a concerted effort to develop novel heritable mouse strains via ethylnitrosourea (ENU)-based random mutagenesis. We have complemented this strategy to perform a dominant sensitized screen to identify mouse mutants with altered recovery following treatment with 5-fluoruracil (5-FU). We isolated a heritable line with elevated platelets as well as an overshoot in platelet numbers when exposed to 5-FU. Affected mice also displayed megakaryocytosis and centrilobular hepatic lipidosis. The mutation was mapped to a 8.7Mb region on mouse Chromosome 19, which contained the candidate gene Jak2. The entire coding region of Jak2 was sequenced and a mutation in exon 19 was found. The causative mutation was located at nucleotide 2740 and leads to an A to T transversion in exon 19 of JAK2 and causes a substitution of a Lys to a premature stop codon at amino acid 914. The resulting protein product terminates within the JH1 kinase domain of JAK2. JAK2 914 is distinct from the JAK2 null allele characterized by the Ihle and Pfeffer labs. For example, JAK2−/− embryos die at E12.5, whereas JAK2914/914 embryos survive until E13.5, suggesting that the truncated protein product may serve as a scaffold. Differences were also observed in clonogenic potential of both strains. For example, JAK2+/− mice had increased CFU-C whereas JAK2914/+ were normal. Splenic BFU-E and CFU-C were increased in JAK2+/− mice while both cell types were decreased in JAK2914/+. In contrast, bone marrow CFU-E were increased in both strains of mice and splenic CFU-E were normal in JAK2+/− and JAK2914/+. In addition, both mouse strains display elevated platelets when animals are housed under resting conditions. The hepatic phenotype is phenocopied by Leptin Receptor null mice that are hyperphagic, poorly cold-adapted, sterile and have enhanced fat conversion resulting in lipidosis. In conclusion, a sensitized screen has shown that JAK2 regulates the response to the chemotherapeutic drug, 5-fluorouracil. These findings have significance to potential myelosuppressive effects of the clinical use of 5-FU in colorectal and pancreatic cancer. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Structure of the human hexokinase type I gene and nucleotide sequence of the 5′ flanking region

1998 ◽  
Vol 331 (2) ◽  
pp. 607-613 ◽  
Author(s):  
Annamaria RUZZO ◽  
Francesca ANDREONI ◽  
Mauro MAGNANI
Keyword(s):  
Yeast Artificial Chromosome ◽  
Direct Sequencing ◽  
Artificial Chromosome ◽  
Type I ◽  
Coding Region ◽  
Exon 1 ◽  
Flanking Region ◽  
The Individual ◽  
I Gene ◽  
Hexokinase Type I

This study reports the precise intron/exon boundaries and intron/exon composition of the human hexokinase type I gene. A yeast artificial chromosome containing the hexokinase type I gene was isolated from the yeast artificial chromosome library of the Centre d'Étude du Polymorphisme Humaine. A cosmid sublibrary was created and direct sequencing of the individual cosmids was used to provide the exon/intron organization. The human hexokinase type I gene was found to be composed of 18 exons ranging in size from 63 to 305 bp. Intron 1 is at least 15 kb in length, whereas intron 2 spans at least 10 kb. Overall, the length of the 17 introns ranges from 104 to greater than 15 kb. The entire coding region is contained in at least 75 kb of the gene. The structure of the gene reveals a remarkable conservation of the size of the exons compared with glucokinase and hexokinase type II. Isolation of the 5´ flanking region of the gene revealed a 75–90% identity with the rat sequence. Direct evidence of an alternative red-blood-cell-specific exon 1 located upstream of the 5´ flanking region of the gene is also provided.

Ectopic Transcript Analysis Indicates that Allelic Exclusion is an Important Cause of Type I Protein C Deficiency in Patients with Nonsense and Frameshift Mutations in the PROC Gene

1996 ◽  
Vol 75 (06) ◽  
pp. 870-876 ◽  
Author(s):  
José Manuel Soria ◽  
Lutz-Peter Berg ◽  
Jordi Fontcuberta ◽  
Vijay V Kakkar ◽  
Xavier Estivill ◽  
...  
Keyword(s):  
Splice Site ◽  
Protein C ◽  
Stop Codon ◽  
Premature Stop Codon ◽  
Allelic Exclusion ◽  
Polymorphism Analysis ◽  
Type I ◽  
Protein C Deficiency ◽  
Nonsense Mutations ◽  
Stop Codons

SummaryNonsense mutations, deletions and splice site mutations are a common cause of type I protein C deficiency. Either directly or indirectly by altering the reading frame, these' lesions generate or may generate premature stop codons and could therefore be expected to result in premature termination of translation. In this study, the possibility that such mutations could instead exert their pathological effects at an earlier stage in the expression pathway, through “allelic exclusion” at the RNA level, was investigated. Protein C (PROC) mRNA was analysed in seven Spanish type I protein C deficient patients heterozygous for two nonsense mutations, a 7bp deletion, a 2bp insertion and three splice site mutations. Ectopic RNA transcripts from patient and control lymphocytes were analysed by RT-PCR and direct sequencing of amplified PROC cDNA fragments. The nonsense mutations and the deletion were absent from the cDNAs indicating that only mRNA derived from the normal allele had been expressed. Similarly for the splice site mutations, only normal PROC cDNAs were obtained. In one case, exclusion of the mutated allele could be confirmed by polymorphism analysis. In contrast to these six mutations, the 2 bp insertion was not associated with loss of mRNA from the mutated allele. In this case, cDNA analysis revealed the absence of 19 bases from the PROC mRNA consistent with the generation and utilization of a cryptic splice site 3’ to the site of mutation, which would result in a frameshift and a premature stop codon. It is concluded that allelic exclusion is a common causative mechanism in those cases of type I protein C deficiency which result from mutations that introduce premature stop codons

scholarly journals A Novel Frameshift Mutation of SCNN1G Causing Liddle Syndrome with Normokalemia

2019 ◽  
Vol 32 (8) ◽  
pp. 752-758
Author(s):  
Peng Fan ◽  
Yu-Mo Zhao ◽  
Di Zhang ◽  
Ying Liao ◽  
Kun-Qi Yang ◽  
...  
Keyword(s):  
Genetic Testing ◽  
Frameshift Mutation ◽  
Stop Codon ◽  
Single Gene ◽  
Family Members ◽  
Premature Stop Codon ◽  
Chinese Family ◽  
Autosomal Dominant Disorder ◽  
Liddle Syndrome ◽  
Genetic Sequencing

Abstract BACKGROUND Liddle syndrome (LS) is an autosomal dominant disorder caused by single-gene mutations of the epithelial sodium channel (ENaC). It is characterized by early-onset hypertension, spontaneous hypokalemia and low plasma renin and aldosterone concentrations. In this study, we reported an LS pedigree with normokalemia resulting from a novel SCNN1G frameshift mutation. METHODS Peripheral blood samples were collected from the proband and eight family members for DNA extraction. Next-generation sequencing and Sanger sequencing were performed to identify the SCNN1G mutation. Clinical examinations were used to comprehensively evaluate the phenotypes of two patients. RESULTS Genetic analysis identified a novel SCNN1G frameshift mutation, p.Arg586Valfs*598, in the proband with LS. This heterozygous frameshift mutation generated a premature stop codon and deleted the vital PY motif of ENaC. The same mutation was present in his elder brother with LS, and his mother without any LS symptoms. Biochemical examination showed normokalemia in the three mutation carriers. The mutation identified was not found in any other family members, 100 hypertensives, or 100 healthy controls. CONCLUSIONS Our study identified a novel SCNN1G frameshift mutation in a Chinese family with LS, expanding the genetic spectrum of SCNN1G. Genetic testing helped us identify LS with a pathogenic mutation when the genotypes and phenotype were not completely consistent because of the hypokalemia. This case emphasizes that once a proband is diagnosed with LS by genetic testing, family genetic sequencing is necessary for early diagnosis and intervention for other family members, to protect against severe cardiovascular complications.

Use of CSGE, TspRI- RFLP and Western Blot in Carrier Detection in an Indian Family with Type I Glanzmann Thrombasthenia.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3975-3975 ◽  
Author(s):  
Meganathan Kannan ◽  
Firdos Ahmad ◽  
Rajive Kumar ◽  
Ved P. Choudhry ◽  
Renu Saxena
Keyword(s):  
Flow Cytometry ◽  
Western Blot ◽  
Family Members ◽  
Carrier Detection ◽  
Carrier Status ◽  
Type I ◽  
Restriction Digestion ◽  
Glanzmann Thrombasthenia ◽  
The Family ◽  
Abnormal Band

Abstract Glanzmann Thrombasthenia (GT) is an inherited, autosomal recessive, bleeding disorder which is characterized by absent/reduced platelet Glycoprotein IIb/IIIa. The sub classification of GT into Types I, II and III is based on the levels of GPIIb/IIIa by flow cytometry. Type I is the most severe form of GT and is found to be most common in north Indian population. Since not much study is available on carrier detection based on western blot analysis, it is suggested to confirm the defect in carriers by molecular diagnosis. Here we present a carrier status using TspRI in a family with Glanzmann Thrombasthenia patient. Glanzmann Thrombasthenia was diagnosed in a patient with bleeding manifestations accompanied by absent platelet aggregation, secondary to ADP, ADR, Arachidonic acid and collagen. The patient was sub typed as Type I based on flow cytometry analysis as he had absent GPIIb/IIIa. Patient’s DNA was analyzed for mutation in both the gpIIb and gpIIIa genes by CSGE, followed by sequencing. The patient was found to have mutation, CTG>CCG at exon 12 of GPIIb gene. The mutation caused amino acid change from Leu to Pro in the GPIIb protein. The same mutation was looked for in all the family members (Both parents and two siblings) using CSGE and by TspRI- RFLP analysis. Both the parents and siblings were heterozygous for this mutation, where as patient was homozygous (Fig 1). As this mutation is not present in the normal individuals and is not reported earlier, this considers being a novel mutation. Presence of abnormal protein in the family members was revealed by western blot analysis for GPIIb (Fig 2). The same mutation is being looked for in more number of patients with Glanzmann Thrombasthenia using TspRI- RFLP. So far, a total of two out of 25 GT patients found to carry this mutation. It is possible that abnormal GPIIb protein by western blot in family members may reflect their carrier status. It is also postulated that western blot and CSGE of GPIIb and IIIa in parents/siblings may detect carrier status in Glanzmann Thrombasthenia. Fig 1: Carrier detection by restriction digestion using TspRI Fig 1:. Carrier detection by restriction digestion using TspRI Fig 2: Immunoblot followed by chemiluminescent detection shows absent/reduced protein in patient and abnormal band pattern in the family members Fig 2:. Immunoblot followed by chemiluminescent detection shows absent/reduced protein in patient and abnormal band pattern in the family members

scholarly journals Premature Stop Codon in MMP20 Causing Amelogenesis Imperfecta

2008 ◽  
Vol 87 (1) ◽  
pp. 56-59 ◽  
Author(s):  
P. Papagerakis ◽  
H.-K. Lin ◽  
K.Y. Lee ◽  
Y. Hu ◽  
J.P. Simmer ◽  
...  
Keyword(s):  
Autosomal Recessive ◽  
Proteolytic Enzymes ◽  
Stop Codon ◽  
Translation Termination ◽  
Premature Stop Codon ◽  
Dental Enamel ◽  
Amino Acid Position ◽  
Amelogenesis Imperfecta ◽  
Exon 1 ◽  
Kallikrein 4

Proteolytic enzymes are necessary for the mineralization of dental enamel during development, and mutations in the kallikrein 4 ( KLK4) and enamelysin ( MMP20) genes cause autosomal-recessive amelogenesis imperfecta (ARAI). So far, only one KLK4 and two MMP20 mutations have been reported. We have identified an ARAI-causing point mutation (c.102G>A, g.102G>A, and p.W34X) in exon 1 of MMP20 in a proband with autosomal-recessive hypoplastic-hypomaturation amelogenesis imperfecta. The G to A transition changes the tryptophan (W) codon (TGG) at amino acid position 34 into a translation termination (X) codon (TGA). No disease-causing sequence variations were detected in KLK4. The affected enamel is thin, with mild spacing in the anterior dentition. The enamel layer is hypomineralized, does not contrast with dentin on radiographs, and tends to chip away from the underlying dentin. An intrinsic yellowish pigmentation is evident, even during eruption. The phenotype supports current ideas concerning the function of enamelysin.

Sign in / Sign up

Export Citation Format

Share Document