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PubMed2024

A novel mutation in SORD gene associated with distal hereditary motor neuropathies.

BACKGROUND: Distal hereditary motor neuropathy (dHMN) is a heterogeneous group of hereditary diseases caused by the gradual degeneration of the lower motor neuron. More than 30 genes associated with dHMN have been reported, while 70-80% of those with the condition are still unable to receive a genetic diagnosis. METHODS: A 26-year-old man experiencing gradual weakness in his lower limbs was referred to our hospital, and data on clinical features, laboratory tests, and electrophysiological tests were collected. To identify the disease-causing mutation, we conducted whole exome sequencing (WES) and then validated it through Sanger sequencing for the proband and his parents. Silico analysis was performed to predict the pathogenesis of the identified mutations. A literature review of all reported mutations of the related gene for the disease was performed. RESULTS: The patient presented with dHMN phenotype harboring a novel homozygous variant c.361G > C (p.Ala121Pro) in SORD, inherited from his parents, respectively. A121 is a highly conserved site and the mutation was categorized as "likely pathogenic" according to the criteria and guidelines of the American College of Medical Genetics and Genomics (ACMG). A total of 13 published articles including 101 patients reported 18 SORD variants. Almost all described cases have the homozygous deletion variant c.757delG (p.A253Qfs*27) or compound heterozygous state of a combination of c.757delG (p.A253Qfs*27) with another variant. The variant c.361G > C (p.Ala121Pro) detected in our patient was the second homozygous variant in SORD-associated hereditary neuropathy. CONCLUSION: One novel homozygous variant c.361G > C (p.Ala121Pro) in SORD was identified in a Chinese patient with dHMN phenotype, which expands the mutation spectrum of SORD-associated hereditary neuropathy and underscores the significance of screening for SORD variants in patients with undiagnosed hereditary neuropathy patients.

Humans↗
PubMed2024

Application of third-generation sequencing technology for identifying rare α- and β-globin gene variants in a Southeast Chinese region.

BACKGROUND: Third-generation sequencing (TGS) based on long-read technology has been gradually used in identifying thalassemia and hemoglobin (Hb) variants. The aim of the present study was to explore genotype varieties of thalassemia and Hb variants in Quanzhou region of Southeast China by TGS. METHODS: Included in this study were 6,174 subjects with thalassemia traits from Quanzhou region of Southeast China. All of them underwent common thalassemia gene testing using the DNA reverse dot-blot hybridization technology. Subjects who were suspected as rare thalassemia carriers were further subjected to TGS to identify rare or novel α- and β-globin gene variants, and the results were verified by Sanger sequencing and/or gap PCR. RESULTS: Of the 6,174 included subjects, 2,390 (38.71%) were identified as α- and β-globin gene mutation carriers, including 40 carrying rare or novel α- and β-thalassemia mutations. The αCD30(-GAG)α and Hb Lepore-Boston-Washington were first reported in Fujian province Southeast China. Moreover, the βCD15(TGG> TAG), βIVS-II-761, β0-Filipino(~ 45 kb deletion), and Hb Lepore-Quanzhou were first identified in the Chinese population. In addition, 35 cases of Hb variants were detected, the rare Hb variants of Hb Jilin and Hb Beijing were first reported in Fujian province of China. Among them, one case with compound αααanti3.7 and Hb G-Honolulu variants was identified in this study. CONCLUSION: Our findings may provide valuable data for enriching the spectrum of thalassemia and highlight the clinical application value of TGS-based α- and β-globin genetic testing.

Humans↗
PubMed2026

Molecular Landscape and Advanced Diagnostic Technologies for BRAF Mutations in Cancer: From Quantitative PCR and ddPCR to CRISPR-Based Platforms.

BRAF mutations are key oncogenic alterations across multiple malignancies, including melanoma, thyroid carcinoma, colorectal cancer, non-small cell lung cancer, glioma, and hairy cell leukemia. The most prevalent variant, BRAF-V600E, induces constitutive activation of the MAPK signaling pathway, promoting tumor progression and influencing therapeutic responsiveness. Accurate detection of BRAF alterations is therefore essential for molecular classification, prognostic assessment, treatment selection, and resistance surveillance. This review summarizes the molecular heterogeneity of BRAF mutations and critically evaluates current diagnostic methodologies. Conventional approaches such as allele-specific PCR and Sanger sequencing are compared with advanced quantitative platforms, including high-resolution melting analysis, droplet digital PCR, and next-generation sequencing, with emphasis on analytical sensitivity, mutation coverage, and clinical applicability. Emerging technologies such as CRISPR-based assays, rolling circle amplification systems, and nanoparticle-based biosensors and point-of-care diagnostic platforms are also discussed for their potential to enhance ultra-sensitive detection, particularly in liquid biopsy settings. These emerging tools are highlighted for their potential to enable ultra-sensitive, rapid, and decentralized mutation detection, particularly in liquid biopsy settings. Key challenges, including intratumoral heterogeneity, low allele-frequency variants, FFPE-associated artifacts, and clonal evolution under therapeutic pressure, are examined within a translational framework. In addition, we examine critical barriers to clinical implementation, including standardization, cost, and global accessibility of molecular diagnostics, and outline potential solutions through scalable technologies and decentralized testing strategies. We propose that optimal BRAF testing requires a mutation subclass-informed and clinically integrated strategy combining comprehensive baseline profiling with longitudinal molecular monitoring. Future diagnostic paradigms will likely integrate multi-omics data and artificial intelligence (AI)-assisted interpretation to refine precision oncology implementation. Looking forward, we propose that optimal BRAF testing will require integration of multi-omics profiling with AI-assisted interpretation, enabling automated variant classification, real-time clinical decision support, and improved prediction of therapeutic response and resistance.

Humans↗
PubMed2025

RELA Haploinsufficiency Manifesting as an Atypical Phenotype of Crohn's Disease.

BACKGROUND: Mutations in RELA, a key component of NF-κB signaling, are associated with dysregulated immune responses and inflammatory disorders. While immunodeficiency phenotypes associated with RELA haploinsufficiency have been reported, gastrointestinal manifestations remain poorly described. This study aimed to characterize the clinical, genomic, and immunological features of a patient presenting with an atypical Crohn's-like phenotype driven by RELA haploinsufficiency. METHODS: Whole-exome sequencing was performed, and results were confirmed by Sanger sequencing. Protein modeling, Western blotting, immunofluorescence, and nuclear extract-based NF-κB activation assays were conducted to assess the functional impact of the identified variant. Immune profiling was performed using mass cytometry time of flight (CyTOF) and single-cell RNA sequencing (scRNA-seq) and compared to controls. RESULTS: We studied a 17-year-old male diagnosed with pan-enteric Crohn's disease (CD), perianal fistulas, chronic mucocutaneous candidiasis, and chronic lymphopenia. Sequencing identified a heterozygous missense variant in RELA (c.587T>C, p.V196A) that potentially impairs RelA (p65) protein stability, confirmed by reduced activity and diminished protein expression. CyTOF analysis revealed decreased circulating T regulatory cells (Tregs), absence of mucosal Tregs, high apoptotic rates, and elevated IFN-γ induced levels, while scRNA-seq demonstrated a robust type I/II interferon signature in multiple immune subsets. Dysregulated mucosal-associated invariant T (MAIT) and cytotoxic CD4+ T cells exhibited upregulation of IL23R and ADAM12, further linking RELA dysfunction to enhanced pro-inflammatory T cell response and tissue inflammation. CONCLUSION: This study links RELA haploinsufficiency with CD-like features, Th1/Th17 polarization, and interferon-driven inflammation, emphasizing the importance of genetic evaluation in patients with atypical or refractory IBD.

Humans↗
PubMed2024

Exome sequencing reveals neurodevelopmental genes in simplex consanguineous Iranian families with syndromic autism.

BACKGROUND AND OBJECTIVE: Autosomal recessive genetic disorders pose significant health challenges in regions where consanguineous marriages are prevalent. The utilization of exome sequencing as a frequently employed methodology has enabled a clear delineation of diagnostic efficacy and mode of inheritance within multiplex consanguineous families. However, these aspects remain less elucidated within simplex families. METHODS: In this study involving 12 unrelated simplex Iranian families presenting syndromic autism, we conducted singleton exome sequencing. The identified genetic variants were validated using Sanger sequencing, and for the missense variants in FOXG1 and DMD, 3D protein structure modeling was carried out to substantiate their pathogenicity. To examine the expression patterns of the candidate genes in the fetal brain, adult brain, and muscle, RT-qPCR was employed. RESULTS: In four families, we detected an autosomal dominant gene (FOXG1), an autosomal recessive gene (CHKB), and two X-linked autism genes (IQSEC2 and DMD), indicating diverse inheritance patterns. In the remaining eight families, we were unable to identify any disease-associated genes. As a result, our variant detection rate stood at 33.3% (4/12), surpassing rates reported in similar studies of smaller cohorts. Among the four newly identified coding variants, three are de novo (heterozygous variant p.Trp546Ter in IQSEC2, heterozygous variant p.Ala188Glu in FOXG1, and hemizygous variant p.Leu211Met in DMD), while the homozygous variant p.Glu128Ter in CHKB was inherited from both healthy heterozygous parents. 3D protein structure modeling was carried out for the missense variants in FOXG1 and DMD, which predicted steric hindrance and spatial inhibition, respectively, supporting the pathogenicity of these human mutants. Additionally, the nonsense variant in CHKB is anticipated to influence its dimerization - crucial for choline kinase function - and the nonsense variant in IQSEC2 is predicted to eliminate three functional domains. Consequently, these distinct variants found in four unrelated individuals with autism are likely indicative of loss-of-function mutations. CONCLUSIONS: In our two syndromic autism families, we discovered variants in two muscular dystrophy genes, DMD and CHKB. Given that DMD and CHKB are recognized for their participation in the non-cognitive manifestations of muscular dystrophy, it indicates that some genes transcend the boundary of apparently unrelated clinical categories, thereby establishing a novel connection between ASD and muscular dystrophy. Our findings also shed light on the complex inheritance patterns observed in Iranian consanguineous simplex families and emphasize the connection between autism spectrum disorder and muscular dystrophy. This underscores a likely genetic convergence between neurodevelopmental and neuromuscular disorders.

Humans↗
PubMed2024

Identifying inversions with breakpoints in the Dystrophin gene through long-read sequencing: report of two cases.

BACKGROUND: Duchenne Muscular Dystrophy (DMD) is an X-linked disorder caused by mutations in the DMD gene, with large deletions being the most common type of mutation. Inversions involving the DMD gene are a less frequent cause of the disorder, largely because they often evade detection by standard diagnostic methods such as multiplex ligation probe amplification (MLPA) and whole exome sequencing (WES). CASE PRESENTATION: Our research identified two intrachromosomal inversions involving the dystrophin gene in two unrelated families through Long-read sequencing (LRS). These variants were subsequently confirmed via Sanger sequencing. The first case involved a pericentric inversion extending from DMD intron 47 to Xq27.3. The second case featured a paracentric inversion between DMD intron 42 and Xp21.1, inherited from the mother. In both cases, simple repeat sequences (SRS) were present at the breakpoints of these inversions. CONCLUSIONS: Our findings demonstrate that LRS is an effective tool for detecting atypical mutations. The identification of SRS at the breakpoints in DMD patients enhances our understanding of the mechanisms underlying structural variations, thereby facilitating the exploration of potential treatments.

Humans↗
PubMed2004

High-throughput mutation detection underlying adaptive evolution of Escherichia coli-K12.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis of base-specific cleavage products is an efficient, highly accurate tool for the detection of single base sequence variations. We describe the first application of this comparative sequencing strategy for automated high-throughput mutation detection in microbial genomes. The method was applied to identify DNA sequence changes that occurred in Escherichia coli K-12 MG1655 during laboratory adaptive evolution to new optimal growth phenotypes. Experiments were based on a genome-scale in silico model of E. coli metabolism and growth. This model computes several phenotypic functions and predicts optimal growth rates. To identify mutations underlying a 40-d adaptive laboratory evolution on glycerol, we resequenced 4.4% of the E. coli-K12 MG1655 genome in several clones picked at the end of the evolutionary process. The 1.54-Mb screen was completed in 13.5 h. This resequencing study is the largest reported by MALDI-TOF mass spectrometry to date. Ten mutations in 40 clones and three deviations from the reference sequence were detected. Mutations were predominantly found within the glycerol kinase gene. Functional characterization of the most prominent mutation shows its metabolic impact on the process of adaptive evolution. All sequence changes were independently confirmed by genotyping and Sanger-sequencing. We demonstrate that comparative sequencing by base-specific cleavage and MALDI-TOF mass spectrometry is an automated, fast, and highly accurate alternative to capillary sequencing.

Adaptation, Biological↗
PubMed2006

Rapid and accurate pyrosequencing of angiosperm plastid genomes.

BACKGROUND: Plastid genome sequence information is vital to several disciplines in plant biology, including phylogenetics and molecular biology. The past five years have witnessed a dramatic increase in the number of completely sequenced plastid genomes, fuelled largely by advances in conventional Sanger sequencing technology. Here we report a further significant reduction in time and cost for plastid genome sequencing through the successful use of a newly available pyrosequencing platform, the Genome Sequencer 20 (GS 20) System (454 Life Sciences Corporation), to rapidly and accurately sequence the whole plastid genomes of the basal eudicot angiosperms Nandina domestica (Berberidaceae) and Platanus occidentalis (Platanaceae). RESULTS: More than 99.75% of each plastid genome was simultaneously obtained during two GS 20 sequence runs, to an average depth of coverage of 24.6x in Nandina and 17.3x in Platanus. The Nandina and Platanus plastid genomes shared essentially identical gene complements and possessed the typical angiosperm plastid structure and gene arrangement. To assess the accuracy of the GS 20 sequence, over 45 kilobases of sequence were generated for each genome using conventional sequencing. Overall error rates of 0.043% and 0.031% were observed in GS 20 sequence for Nandina and Platanus, respectively. More than 97% of all observed errors were associated with homopolymer runs, with approximately 60% of all errors associated with homopolymer runs of 5 or more nucleotides and approximately 50% of all errors associated with regions of extensive homopolymer runs. No substitution errors were present in either genome. Error rates were generally higher in the single-copy and noncoding regions of both plastid genomes relative to the inverted repeat and coding regions. CONCLUSION: Highly accurate and essentially complete sequence information was obtained for the Nandina and Platanus plastid genomes using the GS 20 System. More importantly, the high accuracy observed in the GS 20 plastid genome sequence was generated for a significant reduction in time and cost over traditional shotgun-based genome sequencing techniques, although with approximately half the coverage of previously reported GS 20 de novo genome sequence. The GS 20 should be broadly applicable to angiosperm plastid genome sequencing, and therefore promises to expand the scale of plant genetic and phylogenetic research dramatically.

Base Sequence↗
PubMed2025

Exploring the c.406 C > T variant in TNNI3 gene: pathogenic insights into restrictive cardiomyopathy.

BACKGROUND: Restrictive cardiomyopathy (RCM) is a rare cardiac disorder characterized by diastolic dysfunction and myocardial stiffness, frequently associated with genetic variants. We aimed to explore the genetic basis of RCM in a diagnosed patient through comprehensive genetic analysis. METHODS: Whole exome sequencing (WES) was conducted on the proband, followed by Sanger sequencing for variant confirmation and familial segregation analysis. In silico tools and structural protein modeling were employed to assess the functional impact of the identified variant. RESULTS: The c.406 C > T variant, classified as likely pathogenic, results in a truncated TNNI3 protein. Bioinformatics analysis highlighted significant structural disruptions, likely impairing sarcomere function. The patient presented with growth retardation, progressive dyspnea, and echocardiographic findings consistent with RCM. Both parents were heterozygous carriers, supporting an autosomal recessive inheritance pattern. The homozygosity of the novel variant identified in this study is a critical factor in the genotype-phenotype correlation observed in this case. CONCLUSION: This study identified the novel c.406 C > T variant in TNNI3 as a potential pathogenic driver of RCM, emphasizing the critical role of genetic evaluations in early diagnosis and management of inherited cardiomyopathies. Further studies are warranted to explore therapeutic interventions targeting TNNI3-related pathologies.

Humans↗
PubMed1991

High-sensitivity DNA detection with a laser-excited confocal fluorescence gel scanner.

A high-sensitivity, laser-excited confocal fluorescence gel scanner has been developed and applied to the detection of fluorescently labeled DNA. An argon ion laser (1-10 mW at 488 nm) is focused in the gel with a high-numerical aperture microscope objective. The laser-excited fluorescence is gathered by the objective and focused on a confocal spatial filter, followed by a spectral filter and photodetector. The gel is placed on a computer-controlled scan stage, and the scanned image of the gel fluorescence is stored and analyzed in a computer. This scanner has been used to detect DNA separated on sequencing gels, agarose mapping gels and pulsed field gels. Sanger sequencing gels were run on M13mp18 DNA using a fluoresceinated primer. The 400-microns-thick gels, loaded with 30 fmol of DNA fragments in 3-mm lanes, were scanned at 78-microns resolution. The high resolution of our scanner coupled with image processing allows us to read up to approximately 300 bases in four adjacent sequencing lanes. The minimum band size that could be detected and read was approximately 200 microns. This instrument has a limiting detection sensitivity of approximately 10 amol of fluorescein-labeled DNA in a 1 x 3-mm band. In applications to agarose mapping gels, we have exploited the fact that DNA can be prestained with ethidium homodimer, followed by electrophoresis and fluorescence detection to achieve picogram sensitivity. We have also developed methods using both ethidium homodimer and thiazole orange staining which permit two-color detection of DNA in one lane.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗
PubMed2026

Identification of novel HUWE1 variants in Turner-type X-linked intellectual disability.

OBJECTIVE: To characterize the clinical phenotypes and identify the genetic etiology in four unrelated families affected by Turner-type X-linked intellectual disability (XLID). METHODS: Peripheral blood samples were collected from four probands and their parents. Genomic DNA was extracted, and a comprehensive genetic analysis was performed using trio-based Whole Exome Sequencing (WES) combined with low-pass Copy Number Variation sequencing (CNV-seq). Candidate variants were subsequently validated via Sanger sequencing. RESULTS: Genetic analysis identified distinct variants in the HUWE1 across the four families. Specifically, four distinct HUWE1 variants were identified across the families: a hemizygous c.10034 > T (p.Lys3345Met) in Family 1; a heterozygous c.9209G > A (p.Arg3070His) in Family 2; a heterozygous c.12688T > C (p.Phe4230Leu) in Family 3; and a hemizygous c.9070G > A (p.Ala3024Thr) in Family 4. In accordance with ACMG guidelines, the novel variants in Families 1, 3, and 4 were classified as "Likely Pathogenic" (PS2 + PM2_Supporting + PP2 + PP3). In contrast, the previously reported variant in Family 2 was categorized as "Pathogenic" based on the criteria PS2 + PM2_Supporting + PM5 + PP2 + PP3_Moderate. All probands were clinically diagnosed with Turner-type XLID. CONCLUSIONS: This study expands the pathogenic variant spectrum of HUWE1 and provides novel molecular evidence for the clinical diagnosis of Turner-type XLID. These findings are of significant value for genetic counseling, carrier screening, and prenatal diagnosis for the affected families.

Humans↗
PubMed2025

Exome sequencing identifies a homozygous splice site variant in RP1 as the underlying cause of autosomal recessive retinitis pigmentosa in a Pakistani family.

BACKGROUND: Mutations in RP1 gene are the third leading cause of inherited retinal dystrophies (IRDs) in Pakistani families. PATIENTS: A two-generation consanguineous Pakistani family underwent both clinical and genetic analyses. Clinical examinations included visual acuity test, visual field, fundoscopy, and ocular coherence tomography (OCT). Whole exome sequencing (WES) was performed on the proband's DNA, and Sanger sequencing was performed to validate the WES findings. Splicing prediction tools such as Human Splicing Finder (HSF), NNSplice predictor, SpliceAI, MaxENTScan, and SpliceRover were used. RESULTS: A nuclear family of seven children, comprising five affected individuals (four males and one female) and two healthy siblings, was recruited from northwestern Pakistan. The proband was a 49-years old male who was presented with complaints of decreased visual acuity and night blindness since early childhood. Upon clinical evaluation, the proband appeared to have severely reduced visual acuity of hand movement (HM), bilateral visual field constriction, a waxy pale disc with vascular attenuation, pigmentary bone spicules at the periphery associated with chorioretinal degeneration, diffuse macular atrophy, and horizontal nystagmus in both of his eyes. Exome sequencing (ES) in the proband identified a homozygous splice site variant (NM_006269.2: c.615 + 1G > A) in RP1 gene. In-silico analysis, genotype-phenotype co-segregation study, and literature survey strongly supported the causality of the detected variant. CONCLUSIONS: We report a previously known pathogenic splice site variant of RP1 as the underlying cause of early-onset autosomal recessive retinitis pigmentosa (arRP) in a Pakistani family. We contemplate that the detected allele might constitute a mutational hotspot in RP1.

Humans↗
PubMed2024

LRP4 mutations promote tumor progression and resistance to anti-PD-1 therapy in recurrent hepatocellular carcinoma.

BACKGROUND AND AIMS: HCC recurrence is a major factor limiting long-term survival and the cause of most deaths in patients with HCC. However, molecular characterization and potential therapeutic targets of recurrent HCC remain mostly unknown. APPROACH AND RESULTS: We performed whole-exome sequencing in 63 matched primary and recurrent HCC tumors and combined the data with whole-genome sequencing results in 43 paired samples from our previous study. Sanger sequencing was used to identify all low-density lipoprotein receptor-related protein 4 ( LRP4 ) coding exons in 203 additional patients with recurrent HCC. We identified LRP4 somatic mutations in 7.8% (24/309) of recurrent tumors and only 0.97% (3/309) of primary tumors ( p <0.001). Prognosis after the second liver resection was poorer in patients with an LRP4 mutation. Biofunctional investigations demonstrated that inactivating LRP4 mutations promoted tumor progression and immunosuppression. Mechanistically, mutated LRP4 reduced intratumoral conventional type 1 dendritic cell and CD8 + T cell infiltration by repressing C-C motif chemokine ligand 4 expression and secretion through activation of &#x3b2;-catenin signaling, resulting in resistance to anti-programmed cell death protein-1 therapy. Patients with recurrent HCC carrying an LRP4 mutation did not benefit from anti-programmed cell death protein-1 treatment after their second resection surgery. A &#x3b2;-catenin inhibitor-reversed LRP4-induced resistance to anti-programmed cell death protein-1 therapy in humanized tumor-bearing mice. CONCLUSIONS: Our results identified novel LRP4 mutations important in recurrent HCC. Inactivating LRP4 mutations were associated with resistance to anti-programmed cell death protein-1 therapy and could be useful biomarkers for precision therapy in patients with recurrent HCC.

Humans↗
PubMed2024

A novel splice-altering TNC variant (c.5247A&#x2009;>&#x2009;T, p.Gly1749Gly) in an Chinese family with autosomal dominant non-syndromic hearing loss.

BACKGROUND: This study aims to analyze the pathogenic gene in a Chinese family with non-syndromic hearing loss and identify a novel mutation site in the TNC gene. METHODS: A five-generation Chinese family from Anhui Province, presenting with autosomal dominant non-syndromic hearing loss, was recruited for this study. By analyzing the family history, conducting clinical examinations, and performing genetic analysis, we have thoroughly investigated potential pathogenic factors in this family. The peripheral blood samples were obtained from 20 family members, and the pathogenic genes were identified through whole exome sequencing. Subsequently, the mutation of gene locus was confirmed using Sanger sequencing. The conservation of TNC mutation sites was assessed using Clustal Omega software. We utilized functional prediction software including dbscSNV_AdaBoost, dbscSNV_RandomForest, NNSplice, NetGene2, and Mutation Taster to accurately predict the pathogenicity of these mutations. Furthermore, exon deletions were validated through RT-PCR analysis. RESULTS: The family exhibited autosomal dominant, progressive, post-lingual, non-syndromic hearing loss. A novel synonymous variant (c.5247A&#x2009;>&#x2009;T, p.Gly1749Gly) in TNC was identified in affected members. This variant is situated at the exon-intron junction boundary towards the end of exon 18. Notably, glycine residue at position 1749 is highly conserved across various species. Bioinformatics analysis indicates that this synonymous mutation leads to the disruption of the 5' end donor splicing site in the 18th intron of the TNC gene. Meanwhile, verification experiments have demonstrated that this synonymous mutation disrupts the splicing process of exon 18, leading to complete exon 18 skipping and direct splicing between exons 17 and 19. CONCLUSION: This novel splice-altering variant (c.5247A&#x2009;>&#x2009;T, p.Gly1749Gly) in exon 18 of the TNC gene disrupts normal gene splicing and causes hearing loss among HBD families.

Adult↗
PubMed2004

Sequencing from compomers: using mass spectrometry for DNA de novo sequencing of 200+ nt.

One of the main endeavors in today's life science remains the efficient sequencing of long DNA molecules. Today, most de novo sequencing of DNA is still performed using the electrophoresis-based Sanger concept of 1977, in spite of certain restrictions of this method. Methods using mass spectrometry to acquire the Sanger sequencing data are limited by short sequencing lengths of 15-25 nt. We propose a new method for DNA sequencing using base-specific cleavage and mass spectrometry that appears to be a promising alternative to classical DNA sequencing approaches. A single stranded DNA or RNA molecule is cleaved by a base-specific (bio-)chemical reaction using, for example, RNAses. The cleavage reaction is modified such that not all, but only a certain percentage of bases are cleaved. The resulting mixture of fragments is then analyzed using MALDI-TOF mass spectrometry, whereby we acquire the molecular masses of fragments. For every peak in the mass spectrum, we calculate those base compositions that will potentially create a peak of the observed mass and, repeating the cleavage reaction for all four bases, finally try to uniquely reconstruct the underlying sequence from these observed spectra. This leads us to the combinatorial problem of sequencing from compomers and, finally, to the graph-theoretical problem of finding a walk in a subgraph of the de Bruijn graph. Application of this method to simulated data indicates that it might be capable of sequencing DNA molecules with 200+ nt.

Algorithms↗
PubMed2026

Potential Contribution of DES (p.Leu88Met) and MYH7 (p.Arg787His) Variants to Familial Restrictive Cardiomyopathy.

BACKGROUND: Restrictive cardiomyopathy (RCM) is a rare, severe cardiac disease with a heterogeneous genetic basis. Both genetic and nongenetic factors contribute to RCM pathogenesis. Identifying the underlying molecular causes is important for diagnosis and family screening. In this study, we investigated the genetic basis of RCM in a 52-year-old woman with a family history of RCM and heart disease. METHODS: Genetic predisposition was evaluated using whole-exome sequencing (WES). Candidate variants identified in the proband were validated by Sanger sequencing and interpreted using bioinformatics tools and the American College of Medical Genetics and Genomics/Association for Molecular Pathology (ACMG/AMP) guidelines. RESULTS: Two heterozygous missense variants were identified: a novel DES c.262C&#x2009;>&#x2009;A (p.Leu88Met) variant and a previously reported MYH7 c.2360G&#x2009;>&#x2009;A (p.Arg787His) variant. The DES variant was absent from population databases and was classified as a variant of uncertain significance, whereas the MYH7 variant has been reported in the cardiomyopathy spectrum, primarily in hypertrophic cardiomyopathy. Although both variants may be relevant to the participant's phenotype, their contribution remains uncertain without segregation and functional studies. CONCLUSION: These findings expand the spectrum of DES and MYH7 variants observed in cardiomyopathy and highlight the need for further segregation and functional analyses to clarify their clinical significance in RCM. Identifying the genetic basis of RCM in this family may improve screening strategies and guide clinical management.

DES↗
PubMed1998

Transcriptional sequencing: A method for DNA sequencing using RNA polymerase.

We have developed a sequencing method based on the RNA polymerase chain termination reaction with rhodamine dye attached to 3'-deoxynucleoside triphosphate (3'-dNTP). This method enables us to conduct a rapid isothermal sequencing reaction in <30 min, to reduce the amount of template required, and to do PCR direct sequencing without the elimination of primers and 2'-dNTP, which disturbs the Sanger sequencing reaction. An accurate and longer read length was made possible by newly designed four-color dye-3'-dNTPs and mutated RNA polymerase with an improved incorporation rate of 3'-dNTP. This method should be useful for large-scale sequencing in genome projects and clinical diagnosis.

DNA↗