Search Results (333)

Hereditary ataxias are a highly heterogenous group of diseases characterized by loss of coordination. In this study, we investigated a family of random-bred dogs, in which two siblings were affected by a slowly progressive ataxia. They presented with clinical signs of progressive cerebellar ataxia, hypermetria, and absent menace response. The MRI revealed generalized brain atrophy, reduced cortical demarcation, hypoplastic corpus callosum, and cerebellar folia thinning, highly suggestive of a neurodegenerative disorder. We sequenced the genomes of the two affected dogs and their unaffected parents. Filtering for protein-changing variants that had homozygous alternate genotypes in the affected dogs, heterozygous genotypes in the parents, and homozygous reference genotypes in 1576 control genomes yielded a single missense variant in the RAB24 gene, XM_038534663.1:c.239G>T or XP_038390591.1:p.(Gly80Val). Genotypes at this variant showed the expected co-segregation with the ataxia phenotype in the investigated family. The predicted amino acid affects the conserved RabF4 motif. Glycine-80 resides at the protein surface and the introduction of a hydrophobic isopropyl side chain of the mutant valine might impede solvent accessibility. Another missense variant in RAB24, p.Glu38Pro, was previously reported to cause a clinically similar form of cerebellar ataxia in Gordon Setters and Old English Sheepdogs. Taken together, the available data suggest that RAB24:p.Gly80Val represents the causal variant in the studied dogs. To the best of our knowledge, this is only the second report of a potentially pathogenic RAB24 variant in any species and further supports that RAB24 should be considered a candidate gene in human ataxia patients with unclear molecular etiology. Full article

Background: Spectrin proteins are critical cytoskeleton components that maintain cellular structure and mediate intracellular transport. Pathogenic variants in SPTBN1, encoding βII-spectrin, have been associated with various neurodevelopmental disorders, including developmental delay, intellectual disability, autism spectrum disorder, and epilepsy. Here we report a Korean infant with infantile epileptic spasms syndrome (IESS) and an SPTBN1 mutation and provide a review of this mutation. Methods: The genomic data of the patient were analyzed by whole exome sequencing. A comprehensive literature review was conducted to identify and analyze all reported SPTBN1 variants, resulting in a dataset of 60 unique mutations associated with neurodevelopmental phenotypes. Case Presentation: A 10-month-old Korean female presented with IESS associated with a de novo heterozygous SPTBN1 mutation (c.785A>T; p.Asp262Val). The patient exhibited global developmental delay, microcephaly, hypotonia, spasticity, and MRI findings of diffuse cerebral atrophy and corpus callosum hypoplasia. Electroencephalography revealed hypsarrhythmia, confirming the diagnosis of IESS. Seizures persisted despite initial treatment with vigabatrin and steroids. Genetic analysis identified a likely pathogenic variant within the calponin homology 2 (CH2) domain of SPTBN1. Conclusions: This is the first report of an association between IESS and an SPTBN1 CH2 domain mutation in a Korean infant. This finding expands the clinical spectrum of SPTBN1-related disorders and suggests domain-specific effects may critically influence phenotypic severity. Further functional studies are warranted to elucidate the pathogenic mechanisms of domain-specific variants. Full article

Bacterial blight (BB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is a major threat to global rice productivity. Although hybrid rice breeding has significantly enhanced yields, persistent genetic vulnerabilities within restorer lines continue to compromise BB resistance. This study addresses this challenge by implementing functional marker-assisted selection (FMAS) to pyramid two broad-spectrum resistance (R) genes, Xa21 and Xa23, into the elite, yet BB-susceptible, restorer line K608R. To enable precise Xa23 genotyping, we developed a novel three-primer functional marker (FM) system (IB23/CB23/IR23). This system complements the established U1/I2 markers used for Xa21. This recombination-independent FMAS platform facilitates simultaneous, high-precision tracking of both homozygous and heterozygous alleles, thereby effectively circumventing the linkage drag limitations typical of conventional markers. Through six generations of marker-assisted backcrossing followed by intercrossing, we generated K608R2123 pyramided lines harboring both R genes in homozygous states, achieving a recurrent parent genome recovery rate of 96.93%, as determined by single nucleotide polymorphism (SNP) chip analysis. The pyramided lines exhibited enhanced resistance against six virulent Xoo pathogenic races while retaining parental yield performance across key agronomic traits. Our FMAS strategy overcomes the historical trade-off between broad-spectrum resistance and the preservation of elite phenotypes, with the developed lines exhibiting resistance coverage complementary to that of both introgressed R genes. This integrated approach provides breeders with a reliable molecular tool to accelerate the development of high-yielding, disease-resistant varieties, demonstrating significant potential for practical deployment in rice improvement programs. The K608R2123 germplasm represents a dual-purpose resource suitable for both commercial hybrid seed production and marker-assisted breeding programs, and it confers synergistic resistance against diverse Xoo races, thereby providing a pivotal breeding resource for sustainable BB control in epidemic regions. Full article

Background: This study is the first to investigate the association between colorectal cancer (CRC) risk and the hMLH1 −93G>A and hMSH2 1032G>A polymorphisms of mismatch repair (MMR) genes in the Azerbaijani population. Methods: Peripheral blood samples containing EDTA were collected from the study subjects (134 patients and 137 controls), and genomic DNA was extracted using the non-enzymatic salting-out method. Genotypes were determined by polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP), and the results were visualized through agarose gel electrophoresis. Results: Overall, no statistically significant correlation was observed between CRC risk and the hMLH1 −93G>A polymorphism in the heterozygous GA (OR = 0.760; 95% CI = 0.374–1.542; p = 0.446), the mutant AA (OR = 1.474; 95% CI = 0.738–2.945; p = 0.270), or the A allele (OR = 1.400; 95% CI = 0.984–1.995; p = 0.062). However, in contrast to the dominant model, a statistically significant association was found between the recessive model and an increased CRC risk, with an odds ratio of 1.788 (95% CI = 1.102–2.900; p = 0.018). The hMLH1 −93G>A polymorphism was identified at a significantly higher frequency across the TNM stages, with the distribution showing statistical significance (p < 0.05). Additionally, no statistically significant association was observed between the hMSH2 1032G>A polymorphism and CRC risk. Conclusions: Although no overall association was observed for hMLH1 −93G>A, our findings suggest a potential link with increased colorectal cancer risk under the recessive model in the Azerbaijani population. Further studies are warranted to confirm this model-specific association and investigate the underlying biological mechanisms. Full article

Peters anomaly (PA) is a rare congenital disorder within the anterior segment dysgenesis (ASD) spectrum, characterized by corneal opacity, iridocorneal adhesions, and potential systemic involvement. The genetic basis of PA and related syndromes are complex and incompletely understood. This study investigates novel genetic variants and their clinical impact in two unrelated individuals diagnosed with PA spectrum disorder. Whole-exome sequencing (WES), long-range PCR, and breakpoint analysis were applied to identify pathogenic variants. In the first patient, a heterozygous ~1.6 Mb deletion was detected, spanning the genes PEX2 and ZFHX4 (GRCh37 chr8:g.76760782_78342600del). The second patient carried a heterozygous FOXC1 variant (NM_001453.3:c.310A>G), classified as likely pathogenic. Both variants were confirmed by Sanger sequencing and considered de novo, as they were not present in the biological parents. Clinical evaluations revealed phenotypic variability, with the first patient displaying both ocular and systemic anomalies as in a Peters plus-like syndrome phenotype, while the second patient had isolated ocular manifestations as in a PA type 1 phenotype. These findings expand the genetic landscape of PA, underscoring the importance of comprehensive genomic analysis in subclassifying ASD disorders. Further studies are needed to elucidate the functional consequences of these variants and improve diagnostic and therapeutic strategies. Full article

Waardenburg syndrome (WS) is a rare genetic disorder that affects both hearing and pigmentation. The wide divergence of WS poses significant diagnostic and management challenges. This study investigated type 4 WS within an underrepresented Mongolian population. Whole-exome sequencing revealed that two unique heterozygous variants were identified in the SOX10 gene: c.393C>G (p.Asn131Lys) in a five-year-old female patient presenting with profound sensorineural hearing loss (SNHL), dystopia canthorum, and a white forelock; and c.535A>T (p.Lys179Ter) in a nine-year-old male patient presenting with profound SNHL, dystopia canthorum, and Hirschsprung’s disease. Temporal bone imaging revealed abnormalities in the inner ear structure in both patients. The genotypic and phenotypic characteristics were meticulously delineated, incorporating the deleterious effects of these variants, as evaluated by multiple predictive tools and the American College of Medical Genetics and Genomics (ACMG) criteria. In addition, structural characterizations were also presented using AlphaFold. The findings of this study contribute valuable genetic data to the limited literature on type 4 WS within this ethnic group and highlight the importance of genetic testing and multidisciplinary care for this rare disorder in settings with limited resources. Full article

Perennial ryegrass (Lolium perenne L.) is a cornerstone forage species in temperate dairy systems worldwide, valued for its high yield potential, nutritive quality, and grazing recovery. However, current regional evaluation systems face challenges in accurately assessing complex traits like seasonal dry matter yield due to polygenic nature, environmental variability, and lengthy evaluation cycles. This review examines the evolution of perennial ryegrass evaluation systems, from regional frameworks—like Australia’s Forage Value Index (AU-FVI), New Zealand’s Forage Value Index (NZ-FVI), and Ireland’s Pasture Profit Index (PPI)—to advanced genomic prediction (GP) approaches. We discuss prominent breeding frameworks—F2 family, Half-sib family, and Synthetic Population—and their integration with high-throughput genotyping technologies. Statistical models for GP are compared, including marker-based, kernel-based, and non-parametric approaches, highlighting their strengths in capturing genetic complexity. Key research efforts include representative genotyping approaches for heterozygous populations, disentangling endophyte–host interactions, extending prediction to additional economically important traits, and modeling genotype-by-environment (G × E) interactions. The integration of multi-omics data, advanced phenotyping technologies, and environmental modeling offers promising avenues for enhancing prediction accuracy under changing environmental conditions. By discussing the combination of regional evaluation systems with GP, this review provides comprehensive insights for enhancing perennial ryegrass breeding and evaluation programs, ultimately supporting sustainable productivity of the dairy industry in the face of climate challenges. Full article

Background: Myelotoxicity, usually manifested by moderate leukopenia (particularly neutropenia), is a well-known adverse drug reaction to azathioprine (AZA) therapy. Thiopurine methyltransferase (TMPT) and nucleoside diphosphate-linked moiety X-type motif 15 (NUDT15) genotyping are not routinely performed in patients starting AZA therapy due to their low cost-effectiveness. Additionally, the concomitant use of xanthine oxidase inhibitors and 5-aminosalicylates may slow the metabolism of 6-mercaptopurine. Case Description: We describe a case of a 26-year-old Caucasian man with Crohn’s disease and psoriatic arthritis treated with mesalazine and AZA (100 mg daily) who developed prolonged bone marrow aplasia and neutropenic fever after increasing the daily dose of AZA from 100 to 150 mg (from 44 to 66 mg/m²), without frequent total blood count monitoring. Discontinuation of AZA, multiple transfusions of red blood cells and platelet concentrate, filgrastim, empirical antibiotic therapy, and antiviral and antifungal prophylaxis were obtained after 11 days complete recovery of bone marrow aplasia. Methods: Genomic DNA genotyping of coding regions of TPMT (exons 2–9) and NUDT15 (exons 1–3). Results: Heterozygous alleles in the untranslated region (c.460G>A and c.719A>G) associated with TPMT deficiency and a benign variant (c.*7G>A) in the 3′-UTR of NUDT15 with no effect on enzyme activity were found. Conclusions: This case highlights the importance of monitoring the total blood count frequently during the first weeks of treatment with moderate-to-high doses of AZA. Furthermore, the interaction between AZA and mesalazine may play a significant role in the development of prolonged bone marrow aplasia. Full article

The control of gene expression by cis-regulatory DNA sequences is a conserved genomic feature. The maize booster1 gene (b1) is a naturally occurring locus that serves as a mechanistic model for the control of gene expression from a distal cis element and a form of allelic interactions called paramutation. Two epi-alleles of b1 produce distinct pigmentation phenotypes correlated with transcriptional enhancement and the silencing of b1. These transcriptional dynamics depend on a hepta-tandem repeat sequence located 100 kb upstream of the b1 locus. In the heterozygous condition, the B′ epi-allele paramutates B-I, heritably converting the B-I epi-allele to the epigenetic state and expression level of B′, producing lightly pigmented plants. To identify b1TR-associated proteins, we used a targeted chromatin immunoprecipitation approach with a stably integrated transgenic b1TR locus. Applying a conservative filtering strategy, we detected several expected factors, including RNA Polymerase II, as well as the novel putative DNA-binding proteins ZAG4 and DDT4. ZAG4 and DDT4 activated GAL expression using b1TR as bait in yeast one-hybrid, supporting their potential interaction with this sequence. The identification of proteins uniquely associated with the UAS::b1TR chromatin provides insight into potential b1 regulatory factors and offers a foundation for future studies to investigate their roles in gene regulation. Full article

Objectives: The study investigates runs of homozygosity (ROH) and heterozygosity (ROHet), and their patterns in nine sheep breeds (772 animals in total) maintained in Poland (native and conserved), corresponding to their genetic diversity, inbreeding levels, and selection signatures. Methods: Genotypes were obtained using the Illumina OvineSNP50 BeadChip and quality-filtered SNPs were used to detect ROH and ROHet segments with the detectRUNS R package, following stringent parameters for segment length, SNP density, and genotype quality. Results: Significant variation in ROH characteristics was observed across breeds. Short ROH segments were predominant in all breeds, indicating historical inbreeding events. In contrast, longer ROH segments signified recent inbreeding, particularly in Swiniarka (SW) and Polish Merino of Colored Variety (MPC). The ROH-based genomic inbreeding coefficient (F_ROH) varied across breeds, with SW exhibiting the highest levels, suggesting reduced genetic diversity. ROHet analysis revealed that Uhruska (UHR) had the highest heterozygous segments span, while Black-headed (BH) sheep exhibited the lowest ROHet extent. ROH islands identified across breeds revealed regions under selection, associated with traits such as reproductive performance, wool quality, and body condition. Genes located within these islands (e.g., U6, SPP1, ABCG2) were linked to economically significant traits including milk production, growth, and carcass quality. Conclusions: The presented results highlight the genetic adaptations shaped by selection pressures, while also providing insights into the genetic architecture of sheep breeds maintained in Poland. Full article

Background/Objectives: Pathogenic recessive GJB2 variants are the main genetic cause of non-syndromic sensorineural hearing loss. However, following GJB2 testing, a significant proportion of deaf patients are only found to be heterozygous carriers of pathogenic GJB2 alleles. Five large deletions not affecting GJB2 but encompassing a minimal common 62 kb region within the neighbouring CRYL1 gene have been described to cause loss of cis GJB2 expression and, as a result, produce hearing loss when in trans with pathogenic GJB2 variants. We describe the identification and characterization of a novel deletion of this type in deaf patients from northwestern Spain. Methods: We used panel NGS sequencing to detect the deletion, MLPA to validate it, whole-genome sequencing to map its breakpoints, PCR + Sanger sequencing to finely characterize it and triple-primer PCR to screen for it. Results: We identified a novel 200 kb deletion spanning the whole CRYL1 gene in two unrelated deaf patients from Asturias (in northwestern Spain) who were heterozygous for the pathogenic GJB2 c.35delG variant. Although the large deletion was absent from gnomAD v4.1.0 and 2052 local control alleles, screening for it in 20 additional deaf carriers of monoallelic pathogenic GJB2 variants detected it in another patient from Galicia (also in northwestern Spain). The novel deletion, termed del(200 kb)insATTATA, explained hearing loss in 3/43 (7%) deaf patients from our cohort that were otherwise heterozygous for pathogenic GJB2 variants. Conclusions: This work highlights the importance of comprehensively testing all genomic regions known to be clinically relevant for a given genetic condition, including thorough CRYL1 CNV screening for DFNB1A diagnostics. Full article

Hereditary papillary renal carcinoma (HPRC) is a rare monogenic hereditary disease in the group of hereditary cancer syndromes. Clinically, HPRC results in the development of multiple papillary renal cell carcinomas of the kidneys in young adults. HPRC is caused by point activating mutations in the MET gene encoding a transmembrane tyrosine kinase receptor. Until now, all detected germline mutations in HPRC patients were missense variants leading to a constitutive activation of the tyrosine kinase domain. We describe, for the first time, unrelated patients with clinical features similar to HPRC and without MET pathogenic missense variants but harboring an extended heterozygous duplication ~101.4 kb in length (chr7:116740252-116841718) in 7q31.2 determined using whole-genome sequencing (WGS). This duplication results in an additional copy of the MET gene fragment, including exons 5-21. The duplicated exons encode most of the receptor domains. According to the American College of Medical Genetics and Genomics (ACMG) criteria, this duplication is classified as variant of uncertain significance (VUS) at present, but it is not excluded that this duplication may represent an activating mutation. Perhaps, further segregation analysis and functional studies will allow us to more accurately resolve the pathogenicity and diagnostic significance of this germline CNV. Full article

Friedreich’s ataxia (FRDA) is an autosomal recessive neurodegenerative disorder characterized by ataxia, sensory loss and pyramidal signs. While the majority of FRDA cases are caused by biallelic GAA trinucleotide repeat expansions in intron 1 of FXN, there is a subset of patients harboring a heterozygous pathogenic small variant compound-heterozygous with a GAA repeat expansion. We report on the diagnostic journey of a 21-year-old patient who was clinically suspected of having FRDA at the age of 12 years. Genetic testing included fragment analysis, gene panel analysis and exome sequencing, which only detected one pathogenic heterozygous missense variant (c.389 G>T,p.Gly130Val) in FXN. Although conventional repeat analyses failed to detect GAA expansions in our patient, subsequent short-read genome sequencing (GS) indicated a potential GAA repeat expansion. This finding was confirmed by long-read GS, which in addition revealed a complex pattern of interruptions. Both large and small GAA expansions with divergent interruptions containing G, A, GA, GAG and/or GAAG sequences were present within one allele, indicating mosaic sequence variations. Our findings underscore the complexity of repeat expansions which can exhibit both interruptions and somatic instability. We also highlight the utility of long-read GS in unraveling intricate genetic profiles, ultimately contributing to more accurate diagnoses in clinical practice. Full article

Background: Primary congenital glaucoma (PCG) is a rare disease with an incidence of 1 in 12,000 to 18,000 in Europeans. The scarcity of the disease and limited access to genetic testing have hindered research, particularly within the Latvian population. Objectives: This study aims to present the preliminary results of a molecular genetic investigation into PCG in a Latvian cohort and to compare the prevalence of gene CYP1B1 variants with other European studies as well as to the general population in Latvia. Methods: Twenty probands with clinically diagnosed PCG and 36 family members enrolled in the study. Genetic testing was conducted using genomic DNA from peripheral blood using next generation sequencing (NGS) of seven selected genes: CYP1B1, FOXC1, FOXE3, PXDN, PITX2, PITX3, PAX6, and CPAMD8. Four probands had whole-genome sequencing (WGS). Results: All participants were of European ancestry, with no family history of PCG. Most probands were diagnosed in their first year of life, with a female to male ratio of 1:1.2 and with 80.0% of cases being unilateral. No CYP1B1 pathogenic variants were identified in the screened subjects. However, a heterozygous missense variant c.4357C>A (p.Pro4357Thr) in the PXDN gene was found in one proband and one of her parents that was classified as a variant of uncertain significance. Conclusions: This study represents the first genetic characterization of PCG in the Latvian population. Using NGS, we identified no pathogenic variants in the CYP1B1 gene among affected individuals. Preliminary evidence from this cohort does not support CYP1B1 variants as a predominant cause of PCG, though larger studies are needed to confirm this observation. Comprehensive genetic screening using whole-exome or whole-genome sequencing will be essential to identify the underlying genetic etiology of PCG in Latvia. Full article

Background/Objectives: Pharmacogenomic screening plays a crucial role in optimizing chemotherapy outcomes and minimizing toxicity. Characterizing the baseline distribution of genetic variants in specific populations is essential to inform the prioritization of drug–gene combinations for clinical implementation. The objective of this study was to investigate the distribution of pharmacogenetic variants in 36 genes related to the fluoropyrimidine (FP) pathway among healthy Omani individuals, forming a foundation for future studies in cancer patients receiving FP-based chemotherapy. Methods: Ninety-eight healthy Omani participants aged ≥18 years were recruited at the Sultan Qaboos Comprehensive Cancer Care and Research Center. Whole-blood samples were collected, and genomic DNA was extracted. Targeted next-generation sequencing was performed using a custom Ion AmpliSeq panel covering coding exons and splice-site regions of 36 genes involved in FP metabolism and response. Results: A total of 999 variants were detected across the 36 genes, with 63.3% being heterozygous. The ABCC4 gene had the highest mutation frequency (76 mutations), while DHFR and SMUG1 had the lowest (<10 mutations). In DPYD, four functionally significant variants were found at frequencies ranging from 1 to 8.2% of the population. Missense mutations were also observed in MTHFR and UGT1A1. Three actionable variants in DPYD and MTHFR, associated with 5-fluorouracil and/or capecitabine response, were identified. Additionally, 27 novel single-nucleotide polymorphisms of unknown clinical significance were detected. Conclusions: This study reveals key pharmacogenetic variants in the Omani population, underscoring the importance of integrating pharmacogenomic testing into routine care to support safer, more personalized chemotherapy in the region. Full article