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1.
Acta Myol ; 43(1): 8-15, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38586166

RESUMO

Duchenne muscular dystrophy (DMD) is a devastating X-linked neuromuscular disorder caused by dystrophin gene deletions (75%), duplications (15-20%) and point mutations (5-10%), a small portion of which are nonsense mutations. Women carrying dystrophin gene mutations are commonly unaffected because the wild X allele may produce a sufficient amount of the dystrophin protein. However, approximately 8-10% of them may experience muscle symptoms and 50% of those over 40 years develop cardiomyopathy. The presence of symptoms defines the individual as an affected "symptomatic or manifesting carrier". Though there is no effective cure for DMD, therapies are available to slow the decline of muscle strength and delay the onset and progression of cardiac and respiratory impairment. These include ataluren for patients with nonsense mutations, and antisense oligonucleotides therapies, for patients with specific deletions. Symptomatic DMD female carriers are not included in these indications and little data documenting their management, often entrusted to the discretion of individual doctors, is present in the literature. In this article, we report the clinical and instrumental outcomes of four symptomatic DMD carriers, aged between 26 and 45 years, who were treated with ataluren for 21 to 73 months (average 47.3), and annually evaluated for muscle strength, respiratory and cardiological function. Two patients retain independent ambulation at ages 33 and 45, respectively. None of them developed respiratory involvement or cardiomyopathy. No clinical adverse effects or relevant abnormalities in routine laboratory values, were observed.


Assuntos
Cardiomiopatias , Distrofia Muscular de Duchenne , Oxidiazóis , Humanos , Feminino , Pré-Escolar , Distrofina/genética , Projetos Piloto , Códon sem Sentido , Distrofia Muscular de Duchenne/genética , Distrofia Muscular de Duchenne/terapia
2.
BMC Ophthalmol ; 24(1): 167, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38622537

RESUMO

PURPOSE: The goal of the study was to search for novel bi-allelic CRB1 mutations, and then to analyze the CRB1 literature at the genotypic and phenotypic levels. APPROACH: We screened various variables such as the CRB1 mutation types, domains, exons, and genotypes and their relation with specific ocular phenotypes. An emphasis was given to the bi-allelic missense and nonsense mutations because of their high prevalence compared to other mutation types. Finally, we quantified the effect of various non-modifiable factors over the best-corrected visual acuity oculus uterque (BCVA OU) using multivariate linear regression models and identified genetic interactions. RESULTS: A novel bi-allelic missense in the exon 9 of CRB1; c.2936G > A; p.(Gly979Asp) was found to be associated with rod-cone dystrophy (RCD). CRB1 mutation type, exons, domains, and genotype distribution varied significantly according to fundus characteristics, such as peripheral pigmentation and condition, optic disc, vessels, macular condition, and pigmentation (P < 0.05). Of the 154 articles retrieved from PubMed, 96 studies with 439 bi-allelic CRB1 patients were included. Missense mutations were significantly associated with an absence of macular pigments, pale optic disc, and periphery pigmentation, resulting in a higher risk of RCD (P < 0.05). In contrast, homozygous nonsense mutations were associated with macular pigments, periphery pigments, and a high risk of LCA (P < 0.05) and increased BCVA OU levels. We found that age, mutation types, and inherited retinal diseases were critical determinants of BCVA OU as they significantly increased it by 33% 26%, and 38%, respectively (P < 0.05). Loss of function alleles additively increased the risk of LCA, with nonsense having a more profound effect than indels. Finally, our analysis showed that p.(Cys948Tyr) and p.(Lys801Ter) and p.(Lys801Ter); p.(Cys896Ter) might interact to modify BCVA OU levels. CONCLUSION: This meta-analysis updated the literature and identified genotype-phenotype associations in bi-allelic CRB1 patients.


Assuntos
Códon sem Sentido , Proteínas do Tecido Nervoso , Humanos , Alelos , Proteínas do Tecido Nervoso/genética , Estudos de Associação Genética , Retina , Fenótipo , Mutação , Proteínas do Olho/genética , Linhagem , Análise Mutacional de DNA , Proteínas de Membrana/genética
3.
Cell Stem Cell ; 31(4): 537-553.e5, 2024 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-38579684

RESUMO

In polycystic kidney disease (PKD), microscopic tubules expand into macroscopic cysts. Among the world's most common genetic disorders, PKD is inherited via heterozygous loss-of-function mutations but is theorized to require additional loss of function. To test this, we establish human pluripotent stem cells in allelic series representing four common nonsense mutations, using CRISPR base editing. When differentiated into kidney organoids, homozygous mutants spontaneously form cysts, whereas heterozygous mutants (original or base corrected) express no phenotype. Using these, we identify eukaryotic ribosomal selective glycosides (ERSGs) as PKD therapeutics enabling ribosomal readthrough of these same nonsense mutations. Two different ERSGs not only prevent cyst initiation but also limit growth of pre-formed cysts by partially restoring polycystin expression. Furthermore, glycosides accumulate in cyst epithelia in organoids and mice. Our findings define the human polycystin threshold as a surmountable drug target for pharmacological or gene therapy interventions, with relevance for understanding disease mechanisms and future clinical trials.


Assuntos
Cistos , Doenças Renais Policísticas , Humanos , Camundongos , Animais , Códon sem Sentido/metabolismo , Canais de Cátion TRPP/genética , Canais de Cátion TRPP/metabolismo , Doenças Renais Policísticas/genética , Doenças Renais Policísticas/terapia , Doenças Renais Policísticas/metabolismo , Rim/metabolismo , Organoides/metabolismo , Cistos/genética , Cistos/metabolismo , Glicosídeos/metabolismo
4.
Nat Commun ; 15(1): 2957, 2024 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-38580646

RESUMO

Nonsense mutations - the underlying cause of approximately 11% of all genetic diseases - prematurely terminate protein synthesis by mutating a sense codon to a premature stop or termination codon (PTC). An emerging therapeutic strategy to suppress nonsense defects is to engineer sense-codon decoding tRNAs to readthrough and restore translation at PTCs. However, the readthrough efficiency of the engineered suppressor tRNAs (sup-tRNAs) largely varies in a tissue- and sequence context-dependent manner and has not yet yielded optimal clinical efficacy for many nonsense mutations. Here, we systematically analyze the suppression efficacy at various pathogenic nonsense mutations. We discover that the translation velocity of the sequence upstream of PTCs modulates the sup-tRNA readthrough efficacy. The PTCs most refractory to suppression are embedded in a sequence context translated with an abrupt reversal of the translation speed leading to ribosomal collisions. Moreover, modeling translation velocity using Ribo-seq data can accurately predict the suppression efficacy at PTCs. These results reveal previously unknown molecular signatures contributing to genotype-phenotype relationships and treatment-response heterogeneity, and provide the framework for the development of personalized tRNA-based gene therapies.


Assuntos
Códon sem Sentido , RNA de Transferência , Códon sem Sentido/genética , RNA de Transferência/genética , RNA de Transferência/metabolismo , Códon/genética , Ribossomos/metabolismo , Terapia Genética , Biossíntese de Proteínas/genética , Códon de Terminação
5.
Hemoglobin ; 48(1): 69-70, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38425097

RESUMO

We report two hemoglobinopathy cases involving a novel ß-thalassemia (ß-thal) nonsense mutation, HBB:c.199A > T. One patient had Hb S/ß-thal, and a second unrelated patient had Hb D-Punjab/ß-thal. The HBB:c.199A > T mutation introduces a premature termination codon at amino acid codon 66 (AAA→TAA) in exon 2, resulting in typical high Hb A2 ß0-thal.


Assuntos
Hemoglobinopatias , Talassemia beta , Humanos , Códon sem Sentido , Globinas beta/genética , Mutação , Hemoglobinopatias/genética , Talassemia beta/diagnóstico , Talassemia beta/genética
6.
Nat Commun ; 15(1): 2486, 2024 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-38509072

RESUMO

Protein synthesis terminates when a stop codon enters the ribosome's A-site. Although termination is efficient, stop codon readthrough can occur when a near-cognate tRNA outcompetes release factors during decoding. Seeking to understand readthrough regulation we used a machine learning approach to analyze readthrough efficiency data from published HEK293T ribosome profiling experiments and compared it to comparable yeast experiments. We obtained evidence for the conservation of identities of the stop codon, its context, and 3'-UTR length (when termination is compromised), but not the P-site codon, suggesting a P-site tRNA role in readthrough regulation. Models trained on data from cells treated with the readthrough-promoting drug, G418, accurately predicted readthrough of premature termination codons arising from CFTR nonsense alleles that cause cystic fibrosis. This predictive ability has the potential to aid development of nonsense suppression therapies by predicting a patient's likelihood of improvement in response to drugs given their nonsense mutation sequence context.


Assuntos
Códon sem Sentido , Biossíntese de Proteínas , Humanos , Códon de Terminação/genética , Códon sem Sentido/genética , Células HEK293 , Biossíntese de Proteínas/genética , RNA de Transferência/genética , RNA de Transferência/metabolismo
7.
Int J Mol Sci ; 25(6)2024 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-38542156

RESUMO

mRNAs containing premature stop codons are responsible for various genetic diseases as well as cancers. The truncated proteins synthesized from these aberrant mRNAs are seldom detected due to the nonsense-mediated mRNA decay (NMD) pathway. Such a surveillance mechanism detects most of these aberrant mRNAs and rapidly destroys them from the pool of mRNAs. Here, we implemented chemical cross-linking mass spectrometry (CLMS) techniques to trace novel biology consisting of protein-protein interactions (PPIs) within the NMD machinery. A set of novel complex networks between UPF2 (Regulator of nonsense transcripts 2), SMG1 (Serine/threonine-protein kinase SMG1), and SMG7 from the NMD pathway were identified, among which UPF2 was found as a connection bridge between SMG1 and SMG7. The UPF2 N-terminal formed most interactions with SMG7, and a set of residues emerged from the MIF4G-I, II, and III domains docked with SMG1 or SMG7. SMG1 mediated interactions with initial residues of UPF2, whereas SMG7 formed very few interactions in this region. Modelled structures highlighted that PPIs for UPF2 and SMG1 emerged from the well-defined secondary structures, whereas SMG7 appeared from the connecting loops. Comparing the influence of cancer-derived mutations over different CLMS sites revealed that variants in the PPIs for UPF2 or SMG1 have significant structural stability effects. Our data highlights the protein-protein interface of the SMG1, UPF2, and SMG7 genes that can be used for potential therapeutic approaches. Blocking the NMD pathway could enhance the production of neoantigens or internal cancer vaccines, which could provide a platform to design potential peptide-based vaccines.


Assuntos
Códon sem Sentido , Degradação do RNAm Mediada por Códon sem Sentido , Mutação , RNA Mensageiro/genética , Estrutura Secundária de Proteína , RNA Helicases/metabolismo
8.
Int J Mol Sci ; 25(6)2024 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-38542364

RESUMO

Retinitis pigmentosa 11 is an untreatable, dominantly inherited retinal disease caused by heterozygous mutations in pre-mRNA processing factor 31 PRPF31. The expression level of PRPF31 is linked to incomplete penetrance in affected families; mutation carriers with higher PRPF31 expression can remain asymptomatic. The current study explores an antisense oligonucleotide exon skipping strategy to treat RP11 caused by truncating mutations within PRPF31 exon 12 since it does not appear to encode any domains essential for PRPF31 protein function. Cells derived from a patient carrying a PRPF31 1205C>A nonsense mutation were investigated; PRPF31 transcripts encoded by the 1205C>A allele were undetectable due to nonsense-mediated mRNA decay, resulting in a 46% reduction in PRPF31 mRNA, relative to healthy donor cells. Antisense oligonucleotide-induced skipping of exon 12 rescued the open reading frame with consequent 1.7-fold PRPF31 mRNA upregulation in the RP11 patient fibroblasts. The level of PRPF31 upregulation met the predicted therapeutic threshold of expression inferred in a non-penetrant carrier family member harbouring the same mutation. This study demonstrated increased PRPF31 expression and retention of the nuclear translocation capability for the induced PRPF31 isoform. Future studies should evaluate the function of the induced PRPF31 protein on pre-mRNA splicing in retinal cells to validate the therapeutic approach for amenable RP11-causing mutations.


Assuntos
Oligonucleotídeos Antissenso , Precursores de RNA , Retinite Pigmentosa , Humanos , Precursores de RNA/genética , Oligonucleotídeos Antissenso/genética , Oligonucleotídeos Antissenso/uso terapêutico , Fases de Leitura Aberta , Mutação , Códon sem Sentido , Proteínas do Olho/genética , Proteínas do Olho/metabolismo , Linhagem
9.
EMBO Rep ; 25(4): 2118-2143, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38499809

RESUMO

Stop codon readthrough (SCR) is the process where translation continues beyond a stop codon on an mRNA. Here, we describe a strategy to enhance or induce SCR in a transcript-selective manner using a CRISPR-dCas13 system. Using specific guide RNAs, we target dCas13 to the region downstream of canonical stop codons of mammalian AGO1 and VEGFA mRNAs, known to exhibit natural SCR. Readthrough assays reveal enhanced SCR of these mRNAs (both exogenous and endogenous) caused by the dCas13-gRNA complexes. This effect is associated with ribosomal pausing, which has been reported for several SCR events. Our data show that CRISPR-dCas13 can also induce SCR across premature termination codons (PTCs) in the mRNAs of green fluorescent protein and TP53. We demonstrate the utility of this strategy in the induction of readthrough across the thalassemia-causing PTC in HBB mRNA and hereditary spherocytosis-causing PTC in SPTA1 mRNA. Thus, CRISPR-dCas13 can be programmed to enhance or induce SCR in a transcript-selective and stop codon-specific manner.


Assuntos
Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , RNA Guia de Sistemas CRISPR-Cas , Animais , Códon de Terminação/genética , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas/genética , Códon sem Sentido/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Biossíntese de Proteínas , Mamíferos/genética , Mamíferos/metabolismo
10.
Sci Rep ; 14(1): 7128, 2024 03 26.
Artigo em Inglês | MEDLINE | ID: mdl-38532077

RESUMO

We noticed that during short-term experimental evolution and carcinogenesis, mutations causing gene inactivation (i.e., nonsense mutations or frameshifts) are frequent. Our meta-analysis of 65 experiments using modified dN/dS statistics indicated that nonsense mutations are adaptive in different experimental conditions and we empirically confirmed this prediction. Using yeast S. cerevisiae as a model we show that fixed or highly frequent gene loss-of-function mutations are almost exclusively adaptive in the majority of experiments.


Assuntos
Códon sem Sentido , Saccharomyces cerevisiae , Saccharomyces cerevisiae/genética , Mutação , Mutação da Fase de Leitura , Evolução Molecular
11.
Exp Dermatol ; 33(3): e15042, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38459626

RESUMO

In the context of rare genetic diseases caused by nonsense mutations, the concept of induced stop codon readthrough (SCR) represents an attractive avenue in the ongoing search for improved treatment options. Epidermolysis bullosa (EB)-exemplary for this group of diseases-describes a diverse group of rare, blistering genodermatoses. Characterized by extreme skin fragility upon minor mechanical trauma, the most severe forms often result from nonsense mutations that lead to premature translation termination and loss of function of essential proteins at the dermo-epidermal junction. Since no curative interventions are currently available, medical care is mainly limited to alleviating symptoms and preventing complications. Complementary to attempts of gene, cell and protein therapy in EB, SCR represents a promising medical alternative. While gentamicin has already been examined in several clinical trials involving EB, other potent SCR inducers, such as ataluren, may also show promise in treating the hitherto non-curative disease. In addition to the extensively studied aminoglycosides and their derivatives, several other substance classes-non-aminoglycoside antibiotics and non-aminoglycoside compounds-are currently under investigation. The extensive data gathered in numerous in vitro experiments and the perspectives they reveal in the clinical setting will be discussed in this review.


Assuntos
Códon sem Sentido , Epidermólise Bolhosa , Humanos , Códon de Terminação , Gentamicinas/farmacologia , Gentamicinas/uso terapêutico , Aminoglicosídeos/farmacologia , Aminoglicosídeos/uso terapêutico , Antibacterianos/uso terapêutico , Antibacterianos/farmacologia , Epidermólise Bolhosa/genética , Epidermólise Bolhosa/terapia
12.
Neuromuscul Disord ; 37: 1-5, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38430701

RESUMO

This report describes a novel TTN -related phenotype in two brothers, both affected by a childhood onset, very slowly progressive myopathy with cores, associated with dilated cardiomyopathy only in their late disease stages. Clinical exome sequencing documented in both siblings the heterozygous c.2089A>T and c.19426+2T>A variants in TTN. The c.2089A>T, classified in ClinVar as possibly pathogenic, introduces a premature stop codon in exon 14, whereas the c.19426+2T>A affects TTN alternative splicing. The unfeasibility of segregation studies prevented us from establishing the inheritance mode of the muscle disease in this family, although the lack of any reported muscle or heart symptoms in both parents might support an autosomal recessive transmission. In this view, the occurrence of cardiomyopathy in both probands might be related to the c.2089A>T truncating variant in exon 14, and the childhood onset, slowly progressive myopathy to the c.19426+2T>A splicing variant, possibly allowing translation of an almost full length TTN protein.


Assuntos
Cardiomiopatia Dilatada , Doenças Musculares , Masculino , Humanos , Criança , Conectina/genética , Doenças Musculares/genética , Fenótipo , Cardiomiopatia Dilatada/genética , Cardiomiopatia Dilatada/patologia , Códon sem Sentido , Mutação
13.
J Pharmacol Exp Ther ; 389(2): 186-196, 2024 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-38508753

RESUMO

DNA topoisomerase IIß (TOP2ß/180; 180 kDa) is a nuclear enzyme that regulates DNA topology by generation of short-lived DNA double-strand breaks, primarily during transcription. TOP2ß/180 can be a target for DNA damage-stabilizing anticancer drugs, whose efficacy is often limited by chemoresistance. Our laboratory previously demonstrated reduced levels of TOP2ß/180 (and the paralog TOP2α/170) in an acquired etoposide-resistant human leukemia (K562) clonal cell line, K/VP.5, in part due to overexpression of microRNA-9-3p/5p impacting post-transcriptional events. To evaluate the effect on drug sensitivity upon reduction/elimination of TOP2ß/180, a premature stop codon was generated at the TOP2ß/180 gene exon 19/intron 19 boundary (AGAA//GTAA→ATAG//GTAA) in parental K562 cells (which contain four TOP2ß/180 alleles) by CRISPR/Cas9 editing with homology-directed repair to disrupt production of full-length TOP2ß/180. Gene-edited clones were identified and verified by quantitative polymerase chain reaction and Sanger sequencing, respectively. Characterization of TOP2ß/180 gene-edited clones, with one or all four TOP2ß/180 alleles mutated, revealed partial or complete loss of TOP2ß mRNA/protein, respectively. The loss of TOP2ß/180 protein correlated with decreased (2-{4-[(7-chloro-2-quinoxalinyl)oxy]phenoxy}propionic acid)-induced DNA damage and partial resistance in growth inhibition assays. Partial resistance to mitoxantrone was also noted in the gene-edited clone with all four TOP2ß/180 alleles modified. No cross-resistance to etoposide or mAMSA was noted in the gene-edited clones. Results demonstrated the role of TOP2ß/180 in drug sensitivity/resistance in K562 cells and revealed differential paralog activity of TOP2-targeted agents. SIGNIFICANCE STATEMENT: Data indicated that CRISPR/Cas9 editing of the exon 19/intron 19 boundary in the TOP2ß/180 gene to introduce a premature stop codon resulted in partial to complete disruption of TOP2ß/180 expression in human leukemia (K562) cells depending on the number of edited alleles. Edited clones were partially resistant to mitoxantrone and XK469, while lacking resistance to etoposide and mAMSA. Results demonstrated the import of TOP2ß/180 in drug sensitivity/resistance in K562 cells and revealed differential paralog activity of TOP2-targeted agents.


Assuntos
Antineoplásicos , Leucemia , Humanos , Etoposídeo/farmacologia , Células K562 , DNA Topoisomerases Tipo II/genética , DNA Topoisomerases Tipo II/metabolismo , Mitoxantrona , Sistemas CRISPR-Cas/genética , Códon sem Sentido , Antineoplásicos/farmacologia , DNA , Fenótipo
14.
Stem Cell Res ; 76: 103362, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38417376

RESUMO

Familial hypertrophic cardiomyopathy (HCM) stands as a predominant heart condition, characterised by left ventricle hypertrophy in the absence of any associated loading conditions, with affected individuals having an increased risk of developing heart failure and sudden cardiac death (SCD). Two induced pluripotent stem cell (iPSC) lines were derived from peripheral blood mononuclear cells obtained from two unrelated individuals with previously reported nonsense mutations in the MYBPC3 gene. The first individual is a 48-year-old male (F26) with the MYBPC3 c.1731G > A HCM mutation, whereas the second individual is a 43-year-old female (F82) carrying the MYBPC3 c.2670G > A HCM mutation. The generated iPSCs exhibit appropriate expression of pluripotency markers, trilineage differentiation capacity and a normal karyotype. This resource contributes to gaining deeper insights into the pathophysiological mechanisms that underlie HCM.


Assuntos
Cardiomiopatia Hipertrófica Familiar , Células-Tronco Pluripotentes Induzidas , Masculino , Feminino , Humanos , Adulto , Pessoa de Meia-Idade , Cardiomiopatia Hipertrófica Familiar/genética , Cardiomiopatia Hipertrófica Familiar/metabolismo , Códon sem Sentido , Células-Tronco Pluripotentes Induzidas/metabolismo , Leucócitos Mononucleares , Mutação , Proteínas do Citoesqueleto/genética
15.
Hum Genomics ; 18(1): 22, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38424652

RESUMO

BACKGROUND: To report newly found TSPAN12 mutations with a unique form of familial exudative vitreoretinopathy (FEVR) and find out the possible mechanism of a repeated novel intronic variant in TSPAN12 led to FEVR. RESULTS: Nine TSPAN12 mutations with a unique form of FEVR were detected by panel-based NGS. MINI-Gene assay showed two splicing modes of mRNA that process two different bands A and B, and mutant-type shows replacement with the splicing mode of Exon11 hopping. Construction of wild-type and mutant TSPAN12 vector showed the appearance of premature termination codons (PTC). In vitro expression detection showed significant down-regulated expression level of TSPAN12 mRNAs and proteins in cells transfected with mutant vectors compared with in wild-type group. On the contrary, translation inhibitor CHX and small interfering RNA of UPF1 (si-UPF1) significantly increased mRNA or protein expression of TSPAN12 in cells transfected with the mutant vectors. CONCLUSIONS: Nine mutations in TSPAN12 gene are reported in 9 FEVR patients with a unique series of ocular abnormalities. The three novel TSPAN12 mutations trigger NMD would cause the decrease of TSPAN12 proteins that participate in biosynthesis and assembly of microfibers, which might lead to FEVR, and suggest that intronic sequence analysis might be a vital tool for genetic counseling and prenatal diagnoses.


Assuntos
Códon sem Sentido , Tetraspaninas , Humanos , Vitreorretinopatias Exsudativas Familiares/genética , Vitreorretinopatias Exsudativas Familiares/diagnóstico , Tetraspaninas/genética , Tetraspaninas/metabolismo , Linhagem , Mutação , Análise Mutacional de DNA , Transativadores/genética , RNA Helicases/genética
16.
Prenat Diagn ; 44(4): 519-521, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38342853

RESUMO

A 19-year-old, G1P0, pregnant person was referred at 20w2d gestation for evaluation due to non-immune hydrops fetalis (NIHF), which was confirmed at the time of evaluation. Amniocentesis was performed at 20 w4d, and FISH, karyotype, chromosomal microarray, and exome sequencing (ES) were ordered. Trio ES identified a novel hemizygous c.142 C > T (p.Arg48*; maternally inherited) variant in the FOXP3 gene, resulting in a premature termination codon and establishing the diagnosis of immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome. Intrauterine fetal demise (IUFD) was diagnosed at 21w3d. CVS was performed at 12w1d in a subsequent pregnancy (male fetus) and the known familial variant was identified. NIHF was identified at 18w1d. Ultrasound at 19w2d revealed IUFD. This is the first report of this variant in a diagnosis of IPEX syndrome, presenting with NIHF and male fetal demise. Genotype-phenotype correlations are not available in many cases of IPEX syndrome, as the same genotype can be present with variable severity in different individuals. Given the near identical presentations in this family, we anticipate a more severe phenotype with this variant. We propose a novel variant resulting in an early premature termination codon as an explanation for the severe presentation of IPEX syndrome in two successive fetuses in this family.


Assuntos
Códon sem Sentido , Diabetes Mellitus Tipo 1/congênito , Diarreia , Doenças Genéticas Ligadas ao Cromossomo X , Hidropisia Fetal , Doenças do Sistema Imunitário/congênito , Gravidez , Feminino , Humanos , Masculino , Adulto Jovem , Adulto , Hidropisia Fetal/diagnóstico por imagem , Hidropisia Fetal/genética , Morte Fetal , Fatores de Transcrição Forkhead/genética
17.
J Vet Intern Med ; 38(2): 1160-1166, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38415938

RESUMO

X-linked muscular dystrophy in cats (FXMD) is an uncommon disease, with few reports describing its pathogenic genetic variants. A 9-year-old castrated male domestic shorthair cat was presented with persistent muscle swelling and breathing difficulty from 3 years of age. Serum activity of alanine aminotransferase, aspartate transaminase, and creatine kinase were abnormally high. Physical and neurological examinations showed muscle swelling in the neck and proximal limb, slow gait, and occasional breathing difficulties. Electromyography showed pseudomyotonic discharges and complex repetitive discharges with a "dive-bomber" sound. Histopathology revealed muscle necrosis and regeneration. Whole-genome sequencing identified a novel and unique hemizygous nonsense genetic variant, c.8333G > A in dystrophin (DMD), potentially causing a premature termination codon (p.Trp2778Ter). Based on a combination of clinical and histological findings and the presence of the DMD nonsense genetic variant, this case was considered FXMD, which showed mild clinical signs and long-term survival, even though immunohistochemical characterization was lacking.


Assuntos
Doenças do Gato , Distrofia Muscular de Duchenne , Gatos , Masculino , Animais , Distrofina/genética , Distrofia Muscular de Duchenne/genética , Distrofia Muscular de Duchenne/patologia , Códon sem Sentido , Eletromiografia , Progressão da Doença , Doenças do Gato/genética
18.
BMC Neurol ; 24(1): 73, 2024 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-38383326

RESUMO

BACKGROUND: This paper details the results of an evaluation of the level of consensus amongst clinicians on the use of ataluren in both ambulatory and non-ambulatory patients with nonsense mutation Duchenne muscular dystrophy (nmDMD). The consensus was derived using a modified Delphi methodology that involved an exploration phase and then an evaluation phase. METHODS: The exploration phase involved 90-minute virtual 1:1 interviews of 12 paediatric neurologists who cared for 30-120 DMD patients each and had patient contact every one or two weeks. The respondents managed one to ten nmDMD patients taking ataluren. The Discussion Guide for the interviews can be viewed as Appendix A. Following the exploration phase interviews, the interview transcripts were analysed by an independent party to identify common themes, views and opinions and developed 43 draft statements that the Steering Group (authors) reviewed, refined and endorsed a final list of 42 statements. Details of the recruitment of participants for the exploration and evaluation phases can be found under the Methods section. RESULTS: A consensus was agreed (> 66% of respondents agreeing) for 41 of the 42 statements using results from a consensus survey of healthcare professionals (n = 20) experienced in the treatment of nmDMD. CONCLUSIONS: The statements with a high consensus suggest that treatment with ataluren should be initiated as soon as possible to delay disease progression and allow patients to remain ambulatory for as long as possible. Ataluren is indicated for the treatment of Duchenne muscular dystrophy that results from a nonsense mutation in the dystrophin gene, in ambulatory patients aged 2 years and older (see Summary of Product Characteristics for each country).


Assuntos
Distrofia Muscular de Duchenne , Oxidiazóis , Criança , Humanos , Distrofia Muscular de Duchenne/genética , Distrofia Muscular de Duchenne/terapia , Códon sem Sentido , Grécia , Suécia , Israel , Consenso , Distrofina/genética , Europa Oriental
19.
BMC Genomics ; 25(1): 185, 2024 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-38365607

RESUMO

BACKGROUND: Alpaca is a domestic South American camelid probably arising from the domestication of two wild camelids, the vicugna and the guanaco. Two phenotypes are described for alpaca, known as huacaya and suri. Huacaya fleece is characterized by compact, soft, and highly crimped fibers, while suri fleece is longer, straight, less crimped, and lustrous. The gene variants determining these phenotypes are still unknown, although previous studies suggested a dominant inheritance of the suri. Based on that, the aim of this study was the identification of the gene variants determining alpaca coat phenotypes through whole genome sequencing (WGS) analysis. RESULTS: The sample used includes two test-cross alpaca families, suri × huacaya, which produced two offspring, one with the suri phenotype and one with the huacaya phenotype. The analyzed sample was expanded through the addition of WGS data from six vicugnas and six guanacos; this because we assumed the absence of the gene variants linked to the suri phenotype in these wild species. The analysis of gene variant segregation with the suri phenotype, coupled with the filtering of gene variants present in the wild species, disclosed the presence in all the suri samples of a premature termination codon (PTC) in TRPV3 (transient receptor potential cation channel subfamily V member 3), a gene known to be involved in hair growth and cycling, thermal sensation, cold tolerance and adaptation in several species. Mutations in TRPV3 were previously associated with the alteration of hair structure leading to an impaired formation of the hair canal and the hair shaft in mouse. This PTC in TRPV3, due to a G > T substitution (p.Glu475*), results in a loss of 290 amino acids from the canonical translated protein, plausibly leading to a physiological dysfunction. CONCLUSION: The present results suggest that the suri phenotype may arise from a TRPV3 gene variant which may explain some of the suri features such as its longer hair fibre with lower number of cuticular scales compared to huacaya.


Assuntos
Camelídeos Americanos , Animais , Humanos , Camundongos , Camelídeos Americanos/genética , Códon sem Sentido , Cabelo , Mutação , Fenótipo , Canais de Cátion TRPV/genética , Sequenciamento Completo do Genoma
20.
Stem Cell Res ; 75: 103321, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38301384

RESUMO

Ehlers-Danlos syndrome (EDS) belongs to a spectrum of rare heritable connective tissue disorders and is characterised by hyperextensibility, joint hypermobility and tissue fragility. Peripheral blood mononuclear cells (PBMCs) from a vascular EDS (vEDS) patient, known as the rarest EDS subtype, carrying a heterozygous nonsense mutation c.430C > T (p.Q105*) in the COL3A1 gene, which is essential for type III collagen synthesis, were reprogrammed into induced pluripotent stem cells (iPSCs). The generated iPSCs exhibit high expression of pluripotency-associated markers, possess trilineage differentiation capacity and reveal a normal karyotype. This novel patient-specific cell line enables in-depth pathophysiological studies of vEDS.


Assuntos
Síndrome de Ehlers-Danlos Tipo IV , Síndrome de Ehlers-Danlos , Células-Tronco Pluripotentes Induzidas , Humanos , Códon sem Sentido , Leucócitos Mononucleares , Mutação/genética , Síndrome de Ehlers-Danlos/genética , Colágeno Tipo III/genética
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