Facing ethical concerns in the age of precise gene therapy:Outlook on inherited arrhythmias

This editorial,comments on the article by Spartalis et al published in the recent issue of the World Journal of Cardiology.We here provide an outlook on potential ethical concerns related to the future application of gene therapy in the field of inherited arrhythmias.As monogenic diseases with no or few therapeutic options available through standard care,inherited arrhythmias are ideal candidates to gene therapy in their treatment.Patients with inherited arrhythmias typically have a poor quality of life,especially young people engaged in agonistic sports.While genome editing for treatment of inherited arrhythmias still has theoretical application,advances in CRISPR/Cas9 technology now allows the generation of knock-in animal models of the disease.However,clinical translation is somehow expected soon and this make consistent discussing about ethical concerns related to gene editing in inherited arrhythmias.Genomic off-target activity is a known technical issue,but its relationship with ethnical and individual genetical diversity raises concerns about an equitable accessibility.Meanwhile,the costeffectiveness may further limit an equal distribution of gene therapies.The economic burden of gene therapies on healthcare systems is is increasingly recognized as a pressing concern.A growing body of studies are reporting uncertainty in payback periods with intuitive short-term effects for insurance-based healthcare systems,but potential concerns for universal healthcare systems in the long term as well.Altogether,those aspects strongly indicate a need of regulatory entities to manage those issues.

Automated Classification of Inherited Retinal Diseases in Optical Coherence Tomography Images Using Few-shot Learning

Objective To develop a few-shot learning(FSL) approach for classifying optical coherence tomography(OCT) images in patients with inherited retinal disorders(IRDs).Methods In this study, an FSL model based on a student–teacher learning framework was designed to classify images. 2,317 images from 189 participants were included. Of these, 1,126 images revealed IRDs, 533 were normal samples, and 658 were control samples.Results The FSL model achieved a total accuracy of 0.974–0.983, total sensitivity of 0.934–0.957, total specificity of 0.984–0.990, and total F1 score of 0.935–0.957, which were superior to the total accuracy of the baseline model of 0.943–0.954, total sensitivity of 0.866–0.886, total specificity of 0.962–0.971,and total F1 score of 0.859–0.885. The performance of most subclassifications also exhibited advantages. Moreover, the FSL model had a higher area under curves(AUC) of the receiver operating characteristic(ROC) curves in most subclassifications.Conclusion This study demonstrates the effective use of the FSL model for the classification of OCT images from patients with IRDs, normal, and control participants with a smaller volume of data. The general principle and similar network architectures can also be applied to other retinal diseases with a low prevalence.

SEMI INHERITED BIVARIATE INTERPOLATION

The bivariate interpolation in two dimensional space R2 is more complicated than that in one dimensional space R, because there is no Haar space of continuous functions in R2. Therefore, the bivariate interpolation has not a unique solution for a set of arbitrary distinct pairwise points. In this work, we suggest a type of basis which depends on the points such that the bivariate interpolation has the unique solution for any set of distinct pairwise points. In this case, the matrix of bivariate interpolation has the semi inherited factorization.

HUMAN MITOCHONDRIAL tRNA MUTATIONS IN MATERNALLY INHERITED DEAFNESS

Mutations in mitochondrial tRNA genes have been shown to be associated with maternally inherited syn-dromic and non-syndromic deafness. Among those, mutations such as tRNALeu(UUR) 3243A>G associated with syndromic deafness are often present in heteroplasmy, and the non-syndromic deafness-associated tRNA mu-tations including tRNASer(UCN) 7445A>G are often in homoplasmy or in high levels of heteroplasmy. These tRNA mutations are the primary factors underlying the development of hearing loss. However, other tRNA mutations such as tRNAThr 15927G>A and tRNASer(UCN) 7444G>A are insufficient to produce a deafness phe-notype, but always act in synergy with the primary mitochondrial DNA mutations, and can modulate their phenotypic manifestation. These tRNA mutations may alter the structure and function of the corresponding mitochondrial tRNAs and cause failures in tRNAs metabolism. Thereby, the impairment of mitochondrial protein synthesis and subsequent defects in respiration caused by these tRNA mutations, results in mitochon-drial dysfunctions and eventually leads to the development of hearing loss. Here, we summarized the deaf-ness-associated mitochondrial tRNA mutations and discussed the pathophysiology of these mitochondrial tRNA mutations, and we hope these data will provide a foundation for the early diagnosis, management, and treatment of maternally inherited deafness.

Secret sharing scheme with inherited characteristic

To assure the shareholders can look for their ＂legal＂ attorneys to renew the secret, once the secret sharing scheme is initialized, a secret sharing scheme with inherited characteristic is constructed. In this scheme, each shareholder can produce a new share by his algorithm, which is equivalent to the primary one. Together with other shares, the primary secret can be renewed. Since this scheme is constructed not by replacing the primary share with a new share produced by the dealer in his primitive secret sharing scheme, so no matter how much shares the shareholder produces, these shares can not be gathered together to renew the secret in this scheme. Compared with the existing secret sharing schemes, this scheme provides more agility for the shareholders by investing each of them a function but not affect its security.

Impact of next-generation sequencing on molecular diagnosis of inherited non-syndromic hearing loss

Hearing loss is one of the most common birth defects,with inherited genetic defects play an important role,contributing to about 60%of deafness occurring in infants.However,hearing impairment is genetically heterogeneous,with both common and rare forms occurring due to mutations in estimated 500 genes.Due to the large number and presumably low mutation frequencies of those genes,it would be highly expensive and time-consuming to address this issue by conventional gene-by-gene Sanger sequencing.Next-generation sequencing is a revolutionary technology that allows the simultaneous screening of mutations in a large number of genes.It is cost effective compared to classical strategies of linkage analysis and direct sequencing when the number or size of genes is large,and thus has become a highly efficient strategy for identifying novel causative genes and mutations involved in heritable disease.In this review, we describe major NGS methodologies currently used for genetic disorders and highlight applications of these technologies in studies of molecular diagnosis and the discovery of genes implicated in non-syndromic hearing loss.

Liver transplantation for pediatric inherited metabolic liver diseases

Liver transplantation(LT)remains the gold standard treatment for end stage liver disease in the pediatric population.For liver based metabolic disorders(LBMDs),the decision for LT is predicated on a different set of paradigms.With improved outcomes post-transplantation,LT is no longer merely life saving,but has the potential to also significantly improve quality of life.This review summarizes the clinical presentation,medical treatment and indications for LT for some of the common LBMDs.We also provide a practical update on the dilemmas and controversies surrounding the indications for transplantation,surgical considerations and prognosis and long terms outcomes for pediatric LT in LBMDs.Important progress has been made in understanding these diseases in recent years and with that we outline some of the new therapies that have emerged.

Simultaneous expression of two pathogenic genes in four Chinese patients affected with inherited retinal dystrophy

●AIM:To describe the complex,overlapping phenotype of four Chinese patients with inherited retinal dystrophies(IRDs)who harbored two pathogenic genes simultaneously.●METHODS:This retrospective study included 4 patients affected with IRDs.Medical and ophthalmic histories were obtained,and clinical examinations were performed.A specific Hereditary Eye Disease Enrichment Panel(HEDEP)based on exome capture technology was used for genetic screening.●RESULTS:Four patients were identified to harbor disease-causing variants in two different genes.Patient retinitis pigmentosa(RP)01-II:1 exhibited both classical ABCA4-induced Stargardt disease(STGD)1 and USH2 Aassociated RP,patient RP02-III:2 exhibited both classical ABCA4-induced STGD1 and CDH23-associated RP,patient RP03-II:1 exhibited both USH2 A-induced autosomal recessive retinitis pigmentosa(arRP)syndrome and SNRNP200-induced autosomal dominant retinitis pigmentosa(adRP),and patient RP04-II:2 exhibited USH2 Ainduced arRP syndrome and EYS-induced arRP at the same time.●CONCLUSION:Our study demonstrates that genotype–phenotype correlations and comprehensive genetic screening is crucial for diagnosing IRDs and helping family planning for patients suffering from the disease.

Cellular reprogramming and inherited peripheral neuropathies: perspectives and challenges

Inherited peripheral neuropathies （or Charcot-Marie-Tooth disease, CMT） are a phenotypically and genetically heterogeneous group of disorders, which are currently untreatable. They are the most common inherited neuromuscular disorder, affecting around 1 in every 2,500 people （over 120,000 people in the US）. Based on clinical neurophysiological and histopathological features, inherited neuropathies can be divided into two major forms： demyelinating （type 1） and axonal （type 2） CMT （Saporta, 2014）.

Coenzyme Q10 as a therapeutic candidate for treating inherited photoreceptor degeneration

Inherited photoreceptor degeneration（IPD）：The human retina is a highly specialised tissue that enables the perception of light across a range of intensities and colours.It covers about65%of the inner surface of the eye and contains three layers of cells：the outer nuclear layer（ONL）containing the cell bodies and nuclei of the light-sensitive rod and cone photoreceptorswhose photopigment-containing outer segments form the photoreceptor layer; the inner nuclear layer （INL） containing bipolar, horizontal and amacrine cells; and the ganglion cell layer （GCL） from which the optic nerve arises. There are two layers of synaptic connections between these three layers： the photoreceptors synapse with second order neurons, mainly bi- polar cells, in the outer plexiform layer （OPL）, while in turn the bipolar cells form connections in the inner plexiform layer （IPL） with ganglion cells. The retinal pigment epithelium （RPE） lies directly behind the photoreceptor layer, is heavily pigmented to reduce scattering of light, and is essential for the nourishment, maintenance and metabolism of photoreceptors.

Genetic modifier genes for inherited heart and muscle disease

Genetic mutations in single genes lead to inherited forms of cardiac and muscle disease. Cardiomyopathy from genetic mutations may develop in early or later life and may be associated with heart failure or be asymptomatic.The range of clinical outcome with inherited cardiomyopathy within families where there is a single genetic defect is,in part,determined by other genetic variants.We hypothesized that the interaction of single gene mutations with common genetic variants was responsible for cardiac and muscle disease.In a mouse model, we used a whole genome approach to identify genes that cause more severe heart and muscle disease. We identified a genetic locus on chromosome 7 that was significantly associated with severe disease.We identified the causative gene as Ltbp4,a gene that encodes the latent TGFbeta binding protein.We found that increased TGFbeta signaling was seen in the severely affected heart and muscle compared to the mildly affected strain.We found that increased proteolytic cleavage of LTBP4 protein was associated with increased SMAD signaling.These data support a model where increased proteolytic cleavage of LTBP4 results in increased TGFbeta release and signaling.We also identified other genetic regions that influence the severity of cardiomyopathy in this model.A genetic region on chromosome 9 was specifically associated with increased cardiac fibrosis in cardiomyopathy.Identifying modifier genes helps explain pathways important for modulating heart and muscle disease and may point to pathways that can be used therapeutically.(Supported by NIH,the Muscular Dystrophy Association and the Doris Duke Charitable Foundation.)

Clinical applications of high-throughput genetic diagnosis in inherited retinal dystrophies: Present challenges and future directions

The advent of next generation sequencing(NGS) tech-niques has greatly simplified the molecular diagnosis and gene identification in very rare and highly heterogeneous Mendelian disorders. Over the last two years, these approaches, especially whole exome sequencing(WES), alone or combined with homozygosity mapping and linkage analysis, have proved to be successful in the identification of more than 25 new causative retinal dystrophy genes. NGS-approaches have also identified a wealth of new mutations in previously reported genes and have provided more comprehensive information concerning the landscape of genotype-phenotype correlations and the genetic complexity/diversity of human control populations. Although whole genome sequencing is far more informative than WES, the functional meaning of the genetic variants identified by the latter can be more easily interpreted, and final diagnosis of inherited retinal dystrophies is extremely successful, reaching 80%, particularly for recessive cases. Even considering the present limitations of WES, the reductions in costs and time, the continual technical improvements, the implementation of refined bioinformatic tools and the unbiased comprehensive genetic information it provides, make WES a very promising diagnostic tool for routine clinical and genetic diagnosis in the future.

Retinal imaging in inherited retinal diseases

Inherited retinal diseases(IRD)are a leading cause of blindness in the working age population.The advances in ocular genetics,retinal imaging and molecular biology,have conspired to create the ideal environment for establishing treatments for IRD,with the first approved gene therapy and the commencement of multiple therapy trials.The scope of this review is to familiarize clinicians and scientists with the current landscape of retinal imaging in IRD.Herein we present in a comprehensive and concise manner the imaging findings of:(I)macular dystrophies(MD)[Stargardt disease(ABCA4),X-linked retinoschisis(RS1),Best disease(BEST1),pattern dystrophy(PRPH2),Sorsby fundus dystrophy(TIMP3),and autosomal dominant drusen(EFEMP1)],(II)cone and cone-rod dystrophies(GUCA1A,PRPH2,ABCA4 and RPGR),(III)cone dysfunction syndromes[achromatopsia(CNGA3,CNGB3,PDE6C,PDE6H,GNAT2,ATF6],blue-cone monochromatism(OPN1LW/OPN1MW array),oligocone trichromacy,bradyopsia(RGS9/R9AP)and Bornholm eye disease(OPN1LW/OPN1MW),(IV)Leber congenital amaurosis(GUCY2D,CEP290,CRB1,RDH12,RPE65,TULP1,AIPL1 and NMNAT1),(V)rod-cone dystrophies[retinitis pigmentosa,enhanced S-Cone syndrome(NR2E3),Bietti crystalline corneoretinal dystrophy(CYP4V2)],(VI)rod dysfunction syndromes(congenital stationary night blindness,fundus albipunctatus(RDH5),Oguchi disease(SAG,GRK1),and(VII)chorioretinal dystrophies[choroideremia(CHM),gyrate atrophy(OAT)].

Control of inherited structural fabric on the development and exhumation of passive margins-Insights from the AraçuaíOrogen(Brazil)

The AraçuaíOrogen,in eastern Brazil,was formed during the Neoproterozoic–Cambrian amalgamation of West Gondwana.During the Mesozoic–Cenozoic opening of the South Atlantic Ocean,and the associated divergent tectonics,the orogen developed as basement to the passive margin of South America and was progressively covered by thick offshore sedimentary basins,particularly the Espírito Santo,Mucuri,and Cumuruxatiba basins,in which hydrocarbon systems have been exploited.Our understanding of the AraçuaíOrogen’s passive margin evolution,erosion,and sediment transfer to these basins ultimately depends on constraining the onshore exhumation in response to Mesozoic–Cenozoic events.Here,new and previously published data from apatite fission-track(AFT)analyses and inverse thermal history modelling of(Pre)Cambrian basement rocks from the AraçuaíOrogen resolve three discrete basement cooling and associated erosional exhumation episodes.In the Pre-Rift phase,Jurassic–Hauterivian erosion of the AraçuaíOrogen is most likely related to the adjoining intra-continental West Gondwana flexural subsidence,which increased hillslope and river erosion power.In the Rift and Transitional phases,Barremian–Albian accelerated phase of erosion is associated with the uplift of the Atlantic rift shoulders and the establishment of an oceanic base-level.In the Drift phase,reactivations in response to far-field stresses likely triggered a Late Cretaceous–Paleocene rapid erosion event.The rates at which these events unfolded vary spatially and are controlled by inherited structures.The AraçuaíOrogen experienced slower denudation rates in areas closer to the São Francisco Craton,which suggests that the tectonic reactivation and related surface uplift during the Mesozoic–Cenozoic is in first-order controlled by lithospheric rigidity.Furthermore,the structural framework of the Paramirim and Pirapora aulacogens and NE-oriented shear zones in the orogen’s southeast facilitated later reactivations.From the spatial pattern of denudation/exhumation of the AraçuaíOrogen during the Mesozoic–Cenozoic,we draw inferences on the tectonic development of the offshore basins regarding their hydrocarbon potentials.

Lycium barbarum glycopeptide(wolfberry extract)slows N-methyl-N-nitrosourea-induced degradation of photoreceptors

Photoreceptor cell degeneration leads to blindness, for which there is currently no effective treatment. Our previous studies have shown that Lycium barbarum(L. barbarum) polysaccharide(LBP) protects degenerated photoreceptors in rd1, a transgenic mouse model of retinitis pigmentosa. L. barbarum glycopeptide(Lb GP) is an immunoreactive glycoprotein extracted from LBP. In this study, we investigated the potential protective effect of Lb GP on a chemically induced photoreceptor-degenerative mouse model. Wild-type mice received the following: oral administration of Lb GP as a protective pre-treatment on days 1–7;intraperitoneal administration of 40 mg/kg N-methylN-nitrosourea to induce photoreceptor injury on day 7;and continuation of orally administered Lb GP on days 8–14. Treatment with Lb GP increased photoreceptor survival and improved the structure of photoreceptors, retinal photoresponse, and visual behaviors of mice with photoreceptor degeneration. Lb GP was also found to partially inhibit the activation of microglia in N-methyl-N-nitrosourea-injured retinas and significantly decreased the expression of two pro-inflammatory cytokines. In conclusion, Lb GP effectively slowed the rate of photoreceptor degeneration in N-methyl-N-nitrosourea-injured mice, possibly through an anti-inflammatory mechanism, and has potential as a candidate drug for the clinical treatment of photoreceptor degeneration.

RDH12-associated retinal degeneration caused by a homozygous pathogenic variant of 146C>T and literature review

AIM:To describe the clinical,electrophysiological,and genetic features of an unusual case with an RDH12 homozygous pathogenic variant and reviewed the characteristics of the patients reported with the same variant.METHODS:The patient underwent a complete ophthalmologic examination including best-corrected visual acuity,anterior segment and dilated fundus,visual field,spectral-domain optical coherence tomography(OCT)and electroretinogram(ERG).The retinal disease panel genes were sequenced through chip capture high-throughput sequencing and Sanger sequencing was used to confirm the result.Then we reviewed the characteristics of the patients reported with the same variant.RESULTS:A 30-year male presented with severe early retinal degeneration who complained night blindness,decreased visual acuity,vitreous floaters and amaurosis fugax.The best corrected vision was 0.04 OD and 0.12 OS,respectively.The fundus photo and OCT showed bilateral macular atrophy but larger areas of macular atrophy in the left eye.Autofluorescence shows bilateral symmetrical hypo-autofluorescence.ERG revealed that the amplitudes of a-and b-wave were severely decreased.Multifocal ERG showed decreased amplitudes in the local macular area.A homozygous missense variant c.146C>T(chr14:68191267)was found.The clinical characteristics of a total of 13 patients reported with the same pathologic variant varied.CONCLUSION:An unusual patient with a homozygous pathogenic variant in the c.146C>T of RDH12 which causes late-onset and asymmetric retinal degeneration are reported.The clinical manifestations of the patient with multimodal retinal imaging and functional examinations have enriched our understanding of this disease.

U-Pb Geochronology of Detrital and Inherited Zircons in the Yidun Arc Belt, Eastern Tibet Plateau and Its Tectonic Implications

This paper reports geochronological data of detrital zircons from the country rock and sedimentary xenoliths of the Cilincuo pluton（79±0.7 Ma） in the southern Yidun arc belt and the inherited zircons from the Late Triassic granites in the eastern Yidun arc belt, eastern Tibet Plateau. Detrital zircons ages from the sedimentary xenoliths have four prominent peaks at 2.5–2.4 Ga, 1.9–1.8 Ga, 480–400 Ma, and 350–300 Ma, whereas those from the country rock exhibit another four prominent peaks at 1.9–1.8 Ga, 850–700 Ma, 480–400 Ma, and 300–250 Ma. Based on comparison with age data from previous studies, we suggest that the sedimentary xenoliths are from the Lanashan Formation and the major provenance of them is Qiangtang Block, Zhongza massif and South China Block, whereas the country rock belongs to the Lamaya Formation and the major provenance of them is similar to those of the neighbouring Songpan-Garzê terrane. In addition, the inherited zircons from the Late Triassic granites in the eastern Yidun arc belts have a prominent Neoproterozoic age population（900–700 Ma）, which suggests that there is an old basement with west Yangtze Craton affinity beneath the Triassic sediments. Combining with previous studies, we propose that the provenances of the formations vary from the Lanashan Formation to the Lamaya Formation which may indicate a record of the final closure of the Garzê-Litang Ocean.

The occurrence,inheritance,and segregation of complex genomic structural variation in synthetic Brassica napus

"Synthetic"allopolyploids recreated by interspecific hybridization play an important role in providing novel genomic variation for crop improvement.Such synthetic allopolyploids often undergo rapid genomic structural variation(SV).However,how such SV arises,is inherited and fixed,and how it affects important traits,has rarely been comprehensively and quantitively studied in advanced generation synthetic lines.A better understanding of these processes will aid breeders in knowing how to best utilize synthetic allopolyploids in breeding programs.Here,we analyzed three genetic mapping populations(735 DH lines)derived from crosses between advanced synthetic and conventional Brassica napus(rapeseed)lines,using whole-genome sequencing to determine genome composition.We observed high tolerance of large structural variants,particularly toward the telomeres,and preferential selection for balanced homoeologous exchanges(duplication/deletion events between the A and C genomes resulting in retention of gene/chromosome dosage between homoeologous chromosome pairs),including stable events involving whole chromosomes("pseudoeuploidy").Given the experimental design(all three populations shared a common parent),we were able to observe that parental SV was regularly inherited,showed genetic hitchhiking effects on segregation,and was one of the major factors inducing adjacent novel and larger SV.Surprisingly,novel SV occurred at low frequencies with no significant impacts on observed fertility and yield-related traits in the advanced generation synthetic lines.However,incorporating genome-wide SV in linkage mapping explained significantly more genetic variance for traits.Our results provide a framework for detecting and understanding the occurrence and inheritance of genomic SV in breeding programs,and support the use of synthetic parents as an important source of novel trait variation.

A Theory of Bio-Quantum Genetics

The physical mechanism of heredity or inheritance of genes is a quantum mechanical and/or quantum computational process. A theory of bio-quantum genetics is established in this paper. Principle of Bio-quantum Genetics is suggested. I propose and define the soft-genes of genetics controlling the processes of heredity or inheritance of genes. This research deals with the quantum mechanisms of Mendel plant heredity and family inheritance as examples of bio-quantum genetics, deepening our understanding of heredity or inheritance. I believe that more contributions will be made to promote researches of bio-quantum genetics or quantum biology at large.