A Homozygote Mutation in S-Antigen Visual Arrestin SAG Gene in an Iranian Patient with Oguchi Type One: A Case Report

2020 ◽  
Author(s):  
Hajar ARYAN ◽  
Atekeh BAHADORI ◽  
Dariush D. FARHUD ◽  
Marjan ZARIF YEGANEH ◽  
Haniyeh POURKALHOR
Keyword(s):  
Night Blindness ◽  
Stop Codon ◽  
Molecular Genetic ◽  
Premature Stop Codon ◽  
Molecular Evidence ◽  
Molecular Testing ◽  
Congenital Stationary Night Blindness ◽  
Full Field ◽  
Iranian Patient ◽  
Oguchi Disease

Oguchi disease is a rare autosomal recessive form of congenital stationary night blindness (CSNB) characterized by specific features such as golden-brown discoloration of the fundus called Mizuo-Nakamura phenomenon which is distinguishable by fundoscopy, and retinography. Clinical diagnosis is confirmed through genetic test. Two known genes in pathogenesis of Oguchi disease are SAG and GRK1. A 35-year-old Iranian male exhibiting the clinical features of congenital stationary night blindness, was referred to the genetic clinic of Dr. Farhud, Tehran, Iran in 2012 and examined. Ophthalmic examination including slit-lamp biomicroscopy, perimetry and funduscopy was performed. Additionally, the full-field electroretinography and molecular testing for congenital stationary night blindness were performed. Molecular genetic tests, including the analysis of GSK1 and SAG genes exon-intron boundaries were performed for this patient and his family. According to the sequencing results, we did not find any mutation in GSK1 gene. However, a new homozygote mutation at location chr2:233320735, c.517delC, p.P96LfsX28 was identified in exon four of SAG gene. This deletion causes a frame shift mutation, and premature stop codon that results in deletion of about 281 amino acid residues of S-antigen visual arrestin protein (from entire C-terminal). This mutation was also found in patient’s parents and one of his sister as heterozygote form. This is the first molecular evidence for SAG gene mutation in an Iranian family affected with Oguchi disease type 1. The identification of the new c.517delC, p.P96LfsX28 mutation in this family with Oguchi disease can confirm the pathogenicity of this variant.

scholarly journals Comprehensive Geno- and Phenotyping in a Complex Pedigree Including Four Different Inherited Retinal Dystrophies

Genes ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 137
Author(s):  
Johannes Birtel ◽  
Martin Gliem ◽  
Kristina Hess ◽  
Theresa H. Birtel ◽  
Frank G. Holz ◽  
...  
Keyword(s):  
Genetic Testing ◽  
Night Blindness ◽  
Molecular Genetic ◽  
Cone Dystrophy ◽  
Molecular Testing ◽  
Congenital Stationary Night Blindness ◽  
Molecular Genetic Testing ◽  
Inherited Retinal Dystrophies ◽  
Retinal Dystrophies ◽  
Novel Variant

Inherited retinal dystrophies (IRDs) are characterized by high clinical and genetic heterogeneity. A precise characterization is desirable for diagnosis and has impact on prognosis, patient counseling, and potential therapeutic options. Here, we demonstrate the effectiveness of the combination of in-depth retinal phenotyping and molecular genetic testing in complex pedigrees with different IRDs. Four affected Caucasians and two unaffected relatives were characterized including multimodal retinal imaging, functional testing, and targeted next-generation sequencing. A considerable intrafamilial phenotypic and genotypic heterogeneity was identified. While the parents of the index family presented with rod-cone dystrophy and ABCA4-related retinopathy, their two sons revealed characteristics in the spectrum of incomplete congenital stationary night blindness and ocular albinism, respectively. Molecular testing revealed previously described variants in RHO, ABCA4, and MITF as well as a novel variant in CACNA1F. Identified variants were verified by intrafamilial co-segregation, bioinformatic annotations, and in silico analysis. The coexistence of four independent IRDs caused by distinct mutations and inheritance modes in one pedigree is demonstrated. These findings highlight the complexity of IRDs and underscore the need for the combination of extensive molecular genetic testing and clinical characterization. In addition, a novel variant in the CACNA1F gene is reported associated with incomplete congenital stationary night blindness.

scholarly journals Molecular genetic study in two patients with congenital hypoaldosteronism (types I and II) in relation to previously published hormonal studies

1998 ◽  
pp. 96-100 ◽  
Author(s):  
M Peter ◽  
K Bunger ◽  
SL Drop ◽  
WG Sippell
Keyword(s):  
Genetic Study ◽  
Stop Codon ◽  
Molecular Genetic ◽  
Premature Stop Codon ◽  
Type I ◽  
Type Ii ◽  
Loss Of Function ◽  
Molecular Genetic Study ◽  
Base Exchange ◽  
Deficiency Type

We performed a molecular genetic study in two patients with congenital hypoaldosteronism. An original study of these patients was published in this Journal in 1982. Both index cases, a girl (patient 1) and a boy (patient 2). presented with salt-wasting and failure to thrive in the neonatal period. Parents of patient 1 were not related, whereas the parents of patient 2 were cousins. Endocrine studies had shown a defect in 18-oxidation of 18-OH-corticosterone in patient 1 and a defect in the 18-hydroxylation of corticosterone in patient 2. Plasma aldosterone was decreased in both patients, whereas 18-OH-corticosterone was elevated in patient 1 and decreased in patient 2. Plasma corticosterone and 11-deoxycorticosterone were elevated in both patients, whereas cortisol and its precursors were in the normal range. According to the nomenclature proposed by Ulick, the defects are termed corticosterone methyl oxidase (CMO) deficiency type II in patient 1, and type I in patient 2 respectively. Genetic defects in the gene CYP11B2 encoding aldosterone synthase have been described in a few cases. In patient 1, we identified only one heterozygous amino acid substitution (V386A) in exon 7, which has no deleterious effect on the enzyme activity. In patient 2 and his older brother, we identified a homozygous single base exchange (G to T) in codon 255 (GAG), causing a premature stop codon E255X (TAG). The mutant enzyme has lost the five terminal exons containing the haem binding site, and is thus a loss of function enzyme. This is only the second report of a patient with CMO deficiency type II without a mutation in the exons and exon-intron boundaries, whereas the biochemical phenotype of the two brothers with CMO deficiency type I can be explained by the patient's genotype.

scholarly journals A clinical case of hereditary papillary thyroid carcinoma associated with a germline DICER1 gene mutation

2017 ◽  
Vol 63 (5) ◽  
pp. 320-324
Author(s):  
Svetlana A. Babinskaya ◽  
Natalia Yu. Kalinchenko ◽  
Alexey A. Ilyin ◽  
Natalia V. Severskaya ◽  
Irina V. Chebotareva ◽  
...  
Keyword(s):  
Thyroid Cancer ◽  
Papillary Thyroid Cancer ◽  
Gene Mutation ◽  
Multinodular Goiter ◽  
Clinical Case ◽  
Stop Codon ◽  
Molecular Genetic ◽  
Premature Stop Codon ◽  
Papillary Thyroid ◽  
Reading Frame

Here, we report a clinical case of isolated papillary thyroid cancer associated with a germline DICER1 gene mutation in a boy and his father. The father underwent surgery for a euthyroid multinodular goiter at the age of 7 and 9 years. On examination at the age of 27 years, he was diagnosed with papillary thyroid cancer. At the age of 7 years, the boy was suspected of having a multinodular goiter (based on thyroid ultrasonography findings); he underwent total thyroidectomy. A histological examination of the surgical material revealed encapsulated papillary carcinoma. Neither boy nor his father had been exposed to radiation or chemotherapy before the diagnosis of papillary thyroid cancer. To clarify the etiology of disease, a molecular genetic testing was performed using next-generation sequencing (NGS). The proband and his parent had a heterozygous thymine deletion in the exon 4 at position 380, which led to a shift in the reading frame with the formation of a premature stop codon (c.380delT p.L127QfsX3).

scholarly journals A Single Base Insertion in F9 Causing Hemophilia B in a Family of Newfoundland–Parti Standard Poodle Hybrid Dogs

Genes ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1491
Author(s):  
Henrike Kuder ◽  
Liubov Sandzhieva-Vuzzo ◽  
Alexandra Kehl ◽  
Jonathan M. Rappaport ◽  
Elisabeth Müller ◽  
...  
Keyword(s):  
Stop Codon ◽  
Molecular Genetic ◽  
Genetic Defect ◽  
Clinical Manifestations ◽  
Premature Stop Codon ◽  
Factor Ix ◽  
Hemophilia B ◽  
Surgical Removal ◽  
Standard Poodle ◽  
Plasma Factor

Hemophilia B is an x-linked recessive hereditary coagulopathy that has been reported in various species. We describe a male Newfoundland–Parti Standard Poodle hybrid puppy and its family with hemophilia B from clinical manifestations to the molecular genetic defect. The index case presented for dyspnea was found to have a mediastinal hematoma, while surgical removal and transfusion support brought some relief, progressive hematoma formations led to humane euthanasia. Sequencing the F9 exons revealed a single nucleotide insertion resulting in a frameshift in the last exon (NM_001003323.2:c.821_822insA), predicted to result in a premature stop codon (NP_001003323.1:p.Asn274LysfsTer23) with a loss of 178 of 459 amino acids. The unexpected high residual plasma factor IX activity (3% to 11% of control) was likely erroneous, but no further studies were performed. Both the purebred Newfoundland dam and her sister were heterozygous for the insertion. Five additional male offspring developed severe hemorrhage and were hemizygous for the F9 variant and/or had a prolonged aPTT. In contrast, other male littermates had normal aPTTs and no evidence of bleeding. While they are related to a common Newfoundland granddam, the prevalence of the pathogenic variant in the Newfoundland breed is currently unknown. These clinical to molecular genetic studies illustrate that precision medicine is achievable in clinical companion animal practice.

scholarly journals Assessing Retinal Structure in Complete Congenital Stationary Night Blindness and Oguchi Disease

2012 ◽  
Vol 154 (6) ◽  
pp. 987-1001.e1 ◽  
Author(s):  
Pooja Godara ◽  
Robert F. Cooper ◽  
Panagiotis I. Sergouniotis ◽  
Melissa A. Diederichs ◽  
Megan R. Streb ◽  
...  
Keyword(s):  
Night Blindness ◽  
Congenital Stationary Night Blindness ◽  
Oguchi Disease ◽  
Retinal Structure

scholarly journals Mosaicism due to a Somatic Mutation of the Androgen Receptor Gene Determines Phenotype in Androgen Insensitivity Syndrome1

1997 ◽  
Vol 82 (11) ◽  
pp. 3584-3589
Author(s):  
Paul-Martin Holterhus ◽  
Hennie T. Brüggenwirth ◽  
Olaf Hiort ◽  
Annette Kleinkauf-Houcken ◽  
Klaus Kruse ◽  
...  
Keyword(s):  
Androgen Receptor ◽  
Stop Codon ◽  
Receptor Gene ◽  
Molecular Genetic ◽  
Somatic Mosaicism ◽  
Premature Stop Codon ◽  
Tanner Stage ◽  
Careful Examination ◽  
Wild Type ◽  
Androgen Insensitivity

Premature stop codons of the human androgen receptor (AR) gene are usually associated with a complete androgen insensitivity syndrome. We, however, identified an adult patient with a 46,XY karyotype carrying a premature stop codon in exon 1 of the AR gene presenting with signs of partial virilization: pubic hair Tanner stage 4 and clitoral enlargement. No other family members were affected. A point mutation at codon position 172 of the AR gene was detected that replaced the original TTA (Leu) with a premature stop codon TGA (opal). Careful examination of the sequencing gel, however, also identified a wild-type allele, indicating a mosaicism. In addition, elimination of the unique AflII recognition site induced by the mutation was incomplete, thus confirming the coexistence of mutant and wild-type AR alleles in the patient. Normal R1881 binding and a normal 110/112-kDa AR doublet in Western immunoblots consolidated the molecular genetic data by demonstrating the expression of the wild-type AR in the patient’s genital skin fibroblasts. Transfection analysis revealed that only relatively high plasmid concentrations carrying the mutated AR complementary DNA lead to expression of a shortened AR due to downstream reinitiation at methionine 189. Thus, reinitiation does not play a role in the presentation of the phenotype; rather, the partial virilization is caused by the expression of the wild-type AR due to a somatic mosaic. We conclude that somatic mosaicism of the AR gene can represent a substantial factor for the individual phenotype by shifting it to a higher degree of virilization than expected from the genotype of the mutant allele alone.

scholarly journals Hereditary Defect in Biosynthesis of Aldosterone: Aldosterone Synthase Deficiency 1964–19971

1997 ◽  
Vol 82 (11) ◽  
pp. 3525-3528
Author(s):  
Michael Peter ◽  
Lubna Fawaz ◽  
Stenvert L. S. Drop ◽  
Hendrik K. A. Visser ◽  
Wolfgang G. Sippell
Keyword(s):  
Stop Codon ◽  
Molecular Genetic ◽  
Premature Stop Codon ◽  
Type I ◽  
Loss Of Function ◽  
Oxidase Deficiency ◽  
Base Exchange ◽  
Aldosterone Synthase ◽  
Hereditary Defect ◽  
Deficiency Type

We studied two of the three patients with a hereditary defect in the biosynthesis of aldosterone originally described by Visser and Cost in 1964. All three presented as newborns with salt-losing syndrome and failure to thrive. The original biochemical studies showed a defect in the 18-hydroxylation of corticosterone. According to the nomenclature proposed by Ulick, this defect would be termed corticosterone methyl oxidase deficiency type I. We measured plasma steroids in the untreated adult patients and performed molecular genetic studies. Aldosterone and 18-OH-corticosterone were decreased, whereas corticosterone and 11-deoxycorticosterone were elevated, thus confirming the diagnosis of corticosterone methyl oxidase deficiency type I. Cortisol and its precursors were in the normal range. Genetic defects in the gene CYP11B2 encoding aldosterone synthase (P450c11Aldo) have been described in a few cases. We identified a homozygous single base exchange (G to T) in codon 255 (GAG) causing a premature stop codon E255X (TAG). This mutation destroys a Aoc II restriction site. Digestion of a PCR fragment containing exon 4 of CYP11B2 (261 bp) with this restriction enzyme revealed in the two patients homozygous for the E255X mutation only a 261-bp fragment, whereas the heterozygous parents had three fragments (261 bp from the mutant allele and 194 and 67 bp from the wild-type allele). The mutant enzyme had lost the five terminal exons containing the heme binding site, and thus there was a loss of function enzyme. We conclude that the biochemical phenotype of these prismatic cases of congenital hypoaldosteronism can be explained by the patients genotype.

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

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