A novel nonsense mutation of GPR143 gene in a Korean kindred with X-linked congenital nystagmus

Dear Editor,I am Dr.Ungsoo Samuel Kim.from Kim＇s Eye Hospital,Konyang University,Seoul,Korea.I write to present a novel mutation of GPR143 in Korean patients with X-linked congenital nystagmus by using exome sequencing.Congenital nystagmus is an inherited ocular disorder that can occur as an X-linked condition.

Targeted next-generation sequencing identifies a novel nonsense mutation in ANK1 for hereditary spherocytosis:A case report

BACKGROUND Hereditary spherocytosis(HS)is characterized by anemia,jaundice,splenomegaly,and cholelithiasis,and is caused by abnormal genes encoding red blood cell membrane components.The most common mutations found in HS are in the ANK1 gene.CASE SUMMARY A 4-mo-old girl was admitted to our hospital with pallor that had lasted for more than 2 mo.She presented with jaundice,anemia and splenomegaly.A heterozygous mutation of ANK1(exon23:c.G2467T:p.E823X)was identified,and the mutation was determined to be autosomal dominant.This mutation is linked to the relatively serious anemia she had after birth;this anemia improved with age.CONCLUSION The utilization of next-generation sequencing may assist with the accurate diagnosis of HS,especially in atypical cases.

Application of topical gentamicin ointment in the treatment of Nagashima-type palmoplantar keratosis in children with a nonsense mutation

Importance:Nagashima-type palmoplantar keratosis(NPPK)is a hereditary dermatosis mostly caused by a nonsense mutation in SERPINB7.Despite the increasing interest in readthrough gentamicin treatment of NPPK,clinical evidence for this treatment is limited.Objective:This study aimed to provide further evidence for the use of topical gentamicin in the treatment of NPPK in children with nonsense mutations.Methods:We designed a bilaterally controlled study of topical gentamicin ointment.Children diagnosed with NPPK carrying nonsense mutations were enrolled in this study.A 0.1%gentamicin ointment was applied to one hand and an emollient to the other for 3 months.A bilateral comparison of the visual analog scale scores for clinical manifestations and safety was performed.Results:Ten children with NPPK were included in this study.In comparison with the emollient side,the topical gentamicin side showed significant improvements in hyperkeratosis,erythema,maceration,and desquamation after 1 and 3 months of treatment(P<0.05).However,hyperhidrosis and odor did not improve significantly.No adverse events were observed during the systemic safety monitoring examinations.Interpretation:Topical gentamicin ointment showed good safety in the treatment of NPPK with nonsense mutations,indicating that it is a promising therapeutic choice in children with NPPK.

A novel nonsense mutation in BBS4 gene identified in a Chinese family with Bardet-Biedl syndrome

Background Bardet-Biedl syndrome （BBS） is a genetically heterogeneous disease, and information about BBS in Chinese populations is very limited. The purpose of the present study was to determine the genetic cause of BBS in a Chinese Han family. Methods Clinical data were recorded for the 4-year-old female proband and the available family members. The proband was screened for mutation by Sanger sequencing for a total of 142 exons of the 12 BBS-causing genes （BBS1-BBS12）. The variants detected in the proband were further confirmed in the other family members. Results We identified a novel homozygous nonsense mutation （c.70A〉T, p.K24X） in the BBS4 gene exon 2 in the proband. Such mutant allele was predicted to cause a premature truncation in the N-terminal of the BBS4 protein, and probably induced the nonsense-mediated decay of BBS4 messenger RNAs. The proband＇s parents and brother were heterozygous for the nonsense mutant allele. It was absent in 50 Chinese control subjects. An additional rare heterozygous missense single nucleotide polymorphism （SNP） named rs200718870 in BBS10 gene was also detected in the proband, her father and her brother. Some manifestations of the proband including atypical retinitis pigmentosa, choroidal sclerosis, high myopia, and early onset of obesity might be associated with this mutation in BBS4 gene. The proband＇s father also reported surgical removal of an extra finger during childhood. Conclusions The present study described a novel nonsense mutation in BBS4 gene in a Chinese family. This homozygous mutation was predicted to completely abolish the synthesis of the BBS4 protein. We also detected a rare heterozygous missense SNP in BBSIO gene in the family, but did not find sufficient evidence to support the triallelic inheritance.

Molecular mechanism of microRNA125 regulating human coagulation factor IX gene with nonsense mutation

Objective To construct human coagulation factorⅨmini-gene(Mini-h F9)and some nonsense mutants,detect the levels of the Mini-h F9 mRNA,and analyze the molecular mechanism of microRNA125 regulating F9gene with nonsense mutation.Methods Three nonsense mutants were obtained by using PCR mutagenesis to ana-

Antithrombin gene Arg197Stop mutation-associated venous sinus thrombosis in a Chinese family

This study sought to elucidate the genetic correlation of cerebral venous sinus thrombosis caused by a hereditary antithrombin deficiency in a Chinese family, at the genetic and protein levels. A nonsense mutation from C to T on locus 6431 in exon 3B of the antithrombin gene was observed, leading to an arginine （CGA） to stop codon （TGA） change in the protein. This is the first report of this mutation in China. Ineffective heparin therapy in the propositus patient is associated with a lack of heparin binding sites after antithrombin gene mutation. Characteristic low intracranial pressure in the acute phase might be specific to this patient with cerebral venous sinus thrombosis.

A novel mutation of RPGR in a Chinese family with X-linked retinitis pigmentosa

·AIM:To identify potential mutations and elucidate the clinical findings of male patients and female carriers of X-Iinked retinitis pigmentosa(XLRP)in a Chinese family.·METHODS:A four generation pedigree was collected that consisted of 20 individuals.Genomic DNA was extracted from peripheral blood,and then the target fragments were amplified by PCR and sequenced directly.In addition,all affected patients and female carriers underwent comprehensively ophthalmic evaluation.·RESULTS:A novel mutation c.2865 G>A p.W955 X in RPGR gene was identified of this family,including four affected individuals and eight carriers.All male patients,aging from 7 to 31 y,tended to have more various,even potentially deleterious clinical features of RP.At the same time,individuals with heterozygous mutations(carriers)manifested a wide spectrum of clinical features.Herein,only two male patients and three female carriers manifested pathological myopia(PM).Among the female carriers,half of subjects who harbor poor visual acuity suffered esotropia or exotropia.Additionally,16.7%and 66.7%of carriers had abnormal electroretinogram(ERG)and fundus,respectively.·CONCLUSION:In this study,a novel mutation of the RPGR gene is identified,which broadens the spectrum of RPGR mutations,and elaborates the relationship between genotype and phenotype.

Effect of high-molecular-weight glutenin subunit Dy10 on wheat dough properties and end-use quality

High-molecular-weight glutenin subunits(HMW-GSs) are the most critical grain storage proteins that determine the unique processing qualities of wheat. Although it is a part of the superior HMW-GS pair(Dx5+Dy10), the contribution of the Dy10 subunit to wheat processing quality remains unclear. In this study, we elucidated the effect of Dy10 on wheat processing quality by generating and analyzing a deletion mutant(with the Dy10-null allele), and by elucidating the changes to wheat flour following the incorporation of purified Dy10. The Dy10-null allele was transcribed normally,but the Dy10 subunit was lacking. These findings implied that the Dy10-null allele reduced the glutenin:gliadin ratio and negatively affected dough strength(i.e., Zeleny sedimentation value, gluten index, and dough development and stability times) and the bread-making quality;however, it positively affected the biscuit-making quality. The incorporation of various amounts of purified Dy10 into wheat flour had a detrimental effect on biscuit-making quality. The results of this study demonstrate that the Dy10 subunit is essential for maintaining wheat dough strength. Furthermore, the Dy10-null allele may be exploited by soft wheat breeding programs.

Construction of recombinant plasmid pEGFP-C2-L539fs/47 and its expression in HEK293 cells

Objective:To reconstruct pEGFP-C2-L539fs/47,a HERG nonsense mutant in eukaryotic expression plasmid,and observe the fusion protein expressed in HEK293 cells(human embryo kidney cells).Methods:After double digestion of pcDNA3-L539fs/47 and pEGFP-C2-HERG with sbf I and Eco91 I,the small product fragment,from pcDNA3-L539fs/47,was subcloned into the big fragment of pEGFP-C2-HERG under T4 ligase.pEGFP-C2-L539fs/47 was identified by agarose gel electrophoresis and sequencing.pcDNA3-L539fs/47 and pEGFP-C2-L539fs/47 were transiently transfected into HEK293 cells by Lipofect,respectively.The expression of fusion protein in HEK293 cells was detected through immunofluorescence,laser confocal imaging scanning in vivo,Western blot and PCR.Results:Mutation region cDNA fragment(about 1 kb) and target vector fragment(about 7.2 kb) were ligated after purification and gel recovery.Agarose gel electrophoresis and sequencing successfully demonstrated eukaryotic expression plasmid pEGFP-C2-L539fs/47,constructed approximately 8.2 kb,sequencing consistent with template gene.The transfection efficiency of recombinant plasmid by fluorescence microscopy was more than60%.Western blot analysis detected pcDNA3-L539fs/47 expression of the protein size 60 KD,the expression of pEGFP-C2 fusion protein size of approximately 90 KD.The L539fs/47 gene expression in HEK293 cells was significant by PCR analysis.Confocal laser imaging showed that pEGFP-C2-L539fs/47 protein was successfully expressed in cytoplasm and cytomembrane of HEK293 cells.Conclusion:pEGFP-C2-L539fs/47 containing the HERG gene mutant was successfully constructed by double digestion method and expressed fusion protein in HEK293 cells,which laid a foundation for the further study on L539fs/47.

Suppressor tRNA in gene therapy

Suppressor tRNAs are engineered or naturally occurring transfer RNA molecules that have shown promise in gene therapy for diseases caused by nonsense mutations,which result in premature termination codons(PTCs)in coding sequence,leading to truncated,often nonfunctional proteins.Suppressor t RNAs can recognize and pair with these PTCs,allowing the ribosome to continue translation and produce a full-length protein.This review introduces the mechanism and development of suppressor t RNAs,compares suppressor tRNAs with other readthrough therapies,discusses their potential for clinical therapy,limitations,and obstacles.We also summarize the applications of suppressor tRNAs in both in vitro and in vivo,offering new insights into the research and treatment of nonsense mutation diseases.

Application of topical gentamicin-a new era in the treatment of genodermatosis

Background The clinical use of gentamicin always lies in its antimicrobial activity in the past as an aminoglycoside antibiotic.However,in the past decade,there were considerable interests in therapeutic approaches in treating hereditary diseases.Some of the genodermatosis is caused by nonsense mutations that create premature termination codons and lead to the production of truncated or non-functional proteins.Gentamicin could induce readthrough of nonsense mutations and enable the synthesis of full-length proteins.We focus on previous publications on topical application of gentamicin and review its utility in genetic skin diseases.Data sources We search the MEDLINE through PubMed,EMBASE databases,and the Clinical Trials Registry Platform from January 1960 to July 2020 using the key search terms"gentamicin,topical gentamicin,genodermatosis,genetic skin diseases".Results The application of gentamicin in genodermatosis yielded promising results,both in vivo and in vitro,including Nagashima-type palmoplantar keratosis,epidermolysis bullosa,Hailey-Hailey disease,hereditary hypotrichosis simplex of the scalp,etc.Conclusions Topical gentamicin is a potential treatment option for genodermatosis caused by nonsense mutation.