Deletion Of Exon Research Articles

Significance of Tumor Microvasculature in the Tumor Microenvironment in Adenocarcinoma with EGFR Common Mutations.

Tumor microvasculature is an important component of the tumor microenvironment (TME), and it has been reported that tumor microvasculature induces TME to become immunosuppressive via vascular endothelial growth factor. However, the significance of this in adenocarcinoma with epidermal growth factor receptor (EGFR) common mutations has not been fully investigated. We analyzed 262 patients with adenocarcinoma harboring EGFR common mutations who underwent surgery at Kyushu University Hospital between 2006 and 2021. Microvessel density (MVD) was calculated by CD34 immunohistochemistry. Patients were categorized into high and low MVD status, which was compared with the clinicopathological characteristics. A total of 136 (51.9%) patients had L858R mutation, and 126 (48.1%) had Exon 19 Del. Regarding MVD status; 133 patients (50.8%) were classified as high and 129 (49.2%) as low. Fisher's exact test revealed a significant association of high MVD status with high CD8+ tumor infiltrating lymphocytes (TILs) (p = 0.0187), low GZMB+ TILs (p = 0.0019), and high Foxp3+ TILs (p = 0.0003). On multivariate analysis, MVD status was significantly associated with Foxp3+ TILs and GZMB+ TILs. Fisher's exact test also revealed that tumors with L858R mutation had a high MVD status (p = 0.0136) compared with tumors with deletions of exon 19 (Exon 19 Del), and multivariate analysis revealed that L858R mutation was significantly associated with high MVD status. In adenocarcinomas harboring EGFR common mutations, abundant tumor microvasculature might induce the TME to be immunosuppressive. Tumors with L858R mutation compared with Exon 19 Del might be more likely to form an immunosuppressive TME owing to the abundance of tumor microvasculature.

ALG8-CDG: Advances in Molecular and Prenatal Phenotyping Facilitate Prenatal Diagnosis and Genetic Counseling.

ALG8-congenital disorder of glycosylation (ALG8-CDG) is a rare inherited metabolic disorder leading to severe multisystem manifestations, with no reported prenatal patients to date. We describe two fetuses from a single family with ALG8-CDG presenting with prenatal hydrops, undergoing comprehensive prenatal ultrasound, umbilical cord blood biochemistry, autopsy, placental pathology, and genetic testing. Prenatal ultrasound revealed fetal hydrops, skeletal anomalies, cardiac developmental abnormalities, cataracts, echogenic kidneys and bowel, oligohydramnios, choroid plexus cysts, and intrauterine growth restriction. Umbilical cord blood biochemistry demonstrated fetal anemia, coagulation disorders, and abnormal liver and kidney function. Autopsy confirmed fetal hydrops and associated anomalies. A novel compound heterozygous mutation comprising the missense variant c.754T>C (p.Ser252Pro) and a partial exonic deletion (deletion of exons 1-2) in the ALG8 gene was identified in fetus P2. This study represents the first prenatal diagnosis of ALG8-CDG, comprehensively delineating the prenatal phenotypic spectrum. Prenatal ultrasound, umbilical cord blood biochemistry, and placental pathology findings aid in the assessment of prenatal manifestations, invaluable for prenatal diagnosis, genetic counseling, and potential interventions in future patients.

Prevalence of EGFR Mutations in Patients With Resected Stage I to III Nonsquamous Non-Small Cell Lung Cancer: Results of India Cohort.

The spectrum of EGFR is inadequately researched in patients with early-stage non-small cell lung cancer (NSCLC) in India. EARLY-epidermal growth factor receptor (EGFR) India (ClinicalTrials.gov identifier: NCT04742192), as part of a noninterventional, real-world global study, evaluated the prevalence of EGFR mutations in early-stage NSCLC in India. Prospective data from adult patients with surgically resected stage IA to IIIB (American Joint Committee on Cancer eighth edition) NSCLC between March 2021 and October 2022 were analyzed. In addition to descriptive statistics, Fisher's exact test with Monte Carlo was used to determine the association between EGFR mutations and clinicodemographic parameters. Of 74 patients (median age, 57.0 [range, 33.0-77.0] years) enrolled from eight centers in India, 73.0% (54 of 74) were males, 56.1% (37 of 66) were nonsmokers, and 95.9% (71 of 74) had adenocarcinoma. The EGFR mutation prevalence was 26.0% (19 of 73), of which Exon-19 deletions were the predominant subtype (13, 68.4%) followed by Exon 21-L858R (4, 21.1%), Exon 20-T790M (1, 5.3%), and compound (1, 5.3%) mutations. Nearly half (48.6%, 36 of 74) of the patients underwent only surgical resection. The remaining 51.4% (38 of 74) of the patients were prescribed neoadjuvant (n = 12; 16.2%) and adjuvant (n = 31; 41.9%) systemic therapies, and one patient (1.4%) received radiotherapy along with systemic therapy. In 60 patients with stage IB to IIIB NSCLC, systemic therapies, mainly platinum-based chemotherapy, were prescribed in 36 (60.0%). Only 8.1% (6 of 74) of the patients were prescribed EGFR-tyrosine kinase inhibitor (TKI), of which two received neoadjuvant and four were planned for adjuvant EGFR-TKI. Two (2.7%) patients were prescribed adjuvant immunotherapy. The univariate analysis showed higher odds of EGFR mutation for females (odds ratio, 3.96; P = .017). EARLY-EGFR India results showed the prevalence of EGFR mutation to be 26%. The study emphasized the pressing need for up-front biomarker testing at diagnosis to ensure optimal and timely personalized treatment.

A TMEM260 biallelic deletion underlies truncus arteriosus

Introduction: Truncus arteriosus (TA) is a life-threatening cardiovascular anomaly involving a ventricular septal defect and a common ventricular outflow tract. Recently, biallelic variants in TMEM260 have been identified as causative for Structural Heart Defects and Renal Anomalies syndrome (SHDRA, MIM 617478), which includes TA. Approximately 30 patients with SHDRA have been reported, but the genotype–phenotype correlation remains unclear. Founder variants have been identified in patients of East Asian and Ashkenazi Jewish ancestry. Case Presentation: The male infant, the third child of unrelated Japanese parents, was prenatally diagnosed with TA via detailed ultrasound examination. His older sister also had TA and died at 20 days of age. Despite intensive cardiorespiratory care, the patient passed away at 53 days due to heart failure. Genetic analysis identified a homozygous deletion of TMEM260 exons 6 and 7, resulting from a 7066 bp deletion with a 1 bp insertion, inherited from heterozygous parents. This deletion is included in the structural variation dataset with an allele frequency of 0.00173 (29/8380) in ToMMo 8.3K JPN-SV. Discussion: This is the first familial TA caused by a biallelic structural variation in TMEM260. The 7066-bp deletion shows a high allele frequency in the Japanese population. These findings support the idea that this TMEM260 deletion may be a significant cause of TA and should therefore be considered alongside the previously known c.1617del variant as a potential causative factor.

The prevalence and clinical significance of EGFR mutations in non-small cell lung cancer patients in Egypt: a screening study

BackgroundLung cancer is a form of cancer that is responsible for the largest incidence of deaths attributed to cancer worldwide. Non-small cell lung cancer (NSCLC) is the most prevalent of all the subtypes of the disease. Treatment with tyrosine kinase inhibitors (TKI) may help some people who have been diagnosed with non-small cell lung cancer. The presence of actionable mutations in the epidermal growth factor receptor (EGFR) gene is a key predictor of how a patient will respond to a TKI. Thus, the frequency of identification of mutations in EGFR gene in patients with NSCLC can facilitate personalized treatment.ObjectiveThe objective of this study was to screen for mutations in the EGFR gene and to investigate whether there is a correlation between the screened mutations and various clinical and pathological factors, such as gender, smoking history, and age, in tissue samples from patients with NSCLC.MethodsThe study comprised 333 NSCLC tissue samples from 230 males and 103 females with an average age of 50 years. Exons 18–21 of the EGFR gene have been examined using real-time PCR. Using SPSS, correlations between clinical and demographic variables were examined, and EGFR mutation and clinical features associations were studied.ResultsThe study’s findings revealed that the incidence rate of EGFR mutation was 24.32% (81/333), with partial deletion of exon 19 (19-Del) and a point mutation of L858R in exon 21 accounting for 66.67% (P < 0.001) and 28.40% (P < 0.001) of the mutant cases, respectively. Patients who had the T790M mutation represent 4.94% (P = 0.004) of total number of patients. Females harbored EGFR mutations (54.32%) with higher frequency than men (45.68%) (P < 0.001), while nonsmokers had EGFR mutations (70.37%) more frequently than current smokers (29.63%) (P < 0.001).ConclusionThe screening study conducted in Egypt reported that the EGFR mutations prevalence was 24.32% among Egyptians with NSCLC. The study also found a slight gender bias, with females having an incidence rate of these mutations higher than males. Additionally, nonsmokers had higher rates of mutations in EGFR gene compared to smokers. According to the findings, somatic EGFR mutations can be employed as a diagnostic tool for non-small cell lung cancer in Egypt, and they can be implemented in conjunction with clinical criteria to identify which patients are more likely to respond favorably to TKIs.

Genomic characteristics of Russian patients with non-small cell lung cancer: Results of next-generation sequencing testing

Introduction. Next-generation sequencing (NGS) is a molecular approach that can provide clinicians with comprehensive information about a patient’s molecular profile, which is an important aspect of the effective application of targeted therapy.Aim. To assess the frequency of tumor somatic mutations in non-small cell lung cancer (NSCLC) in a cohort of Russian patients to subsequently optimize diagnostics and personalize treatment strategies.Materials and methods. The study included the results of NGS testing from a cohort of 1.400 NSCLC patients between March 17, 2023, and July 22, 2024. Several other clinics across the country participated in this multicenter study. Panels with various options for identifying potential genetic alterations were used. An analysis of the frequency of various alterations was conducted based on the panel used, clinical characteristics of the patients, considering the geographical and ethnographic diversity of the regions in the country.Results. Mutations were most frequently found in the KRAS (17.9%) and EGFR (15.8%) genes, particularly among never-smoker women. The frequency of rare mutations such as RET, MET, and NTRK corresponds to literature data and underscores the need to expand the group of patients being tested for these alterations. However, deletions in exon 19 of EGFR (12.7%) and KRAS G12C (16.4%) were also found among smokers. The results highlight the inadequate scope of existing testing, partly due to the lack of co-mutation assessment and primary resistance mutations, while also demonstrating possible differences when using various diagnostic panels.Conclusion. The implementation of NGS in public health systems allows for a more personalized approach to selecting treatment strategies for patients. The data obtained can be used in predictive models to optimize drug distribution.

Transcriptional Reprogramming and Allelic Variation in Pleiotropic QTL Regulates Days to Flowering and Growth Habit in Pigeonpea.

The present study investigated the linkage between days to flowering (DTF) and growth habit (GH) in pigeonpea using QTL mapping, QTL-seq, and GWAS approaches. The linkage map developed here is the largest to date, spanning 1825.56 cM with 7987 SNP markers. In total, eight and four QTLs were mapped for DTF and GH, respectively, harbouring 78 pigeonpea orthologs of Arabidopsis flowering time genes. Corroboratively, QTL-seq analysis identified a single linked QTL for both traits on chromosome 3, possessing 15 genes bearing genic variants. Together, these 91 genes were clustered primarily into autonomous, photoperiod, and epigenetic pathways. Further, we identified 39 associations for DTF and 111 associations for GH through GWAS in the QTL regions. Of these, nine associations were consistent and constituted nine haplotypes (five late, two early, one each for super-early and medium duration). The involvement of multiple genes explained the range of allelic effects and the presence of multiple LD blocks. Further, the linked QTL on chromosome 3 was fine-mapped to the 0.24-Mb region with an LOD score of 8.56, explaining 36.47% of the phenotypic variance. We identified a 10-bp deletion in the first exon of TFL1 gene of the ICPL 20338 variety, which may affect its interaction with the Apetala1 and Leafy genes, resulting in determinate GH and early flowering. Further, the genic marker developed for the deletion in the TFL1 gene could be utilized as a foreground marker in marker-assisted breeding programmes to develop early-flowering pigeonpea varieties.

Contribution of large genomic rearrangements in BRCA1/2 genes and CHEK2 1100delC allele variant to the development of breast/ovarian cancer in Argentinian population.

Among women in Argentina, the most common cancer is breast cancer (BC) with 21,631 new cases and 6436 deaths per year. The ovarian cancer (OC) is fifteenth in frequency. The contribution of cancer-related large genomic rearrangements (LGRs) of the BRCA1/BRCA2 genes and the 1100delC allelic variant in the CHEK2 gene has not yet been widely studied in our population. LGRs in the BRCA1/BRCA2 genes and the CHEK2 1100delC variant were analyzed using the MLPA technique in 85 unselected Argentinian BC/OC patients. A pathogenic genetic variant (PV) was found in eleven out of 85 (12,9%) patients, 10 were LGRs in the BRCA1 gene, 9 deletions and one duplication and one the CHEK2 1100delC. Large deletions of exons 1-2 and 15 in BRCA1 gene were recurrent anomalies in our series. LGRs in the BRCA1 gene contributed significantly to the burden of PVs responsible for the development of BC and OC in our study population. On the other hand, the 1100delC variant in CHEK2 was observed at a very low frequency in our series formed mainly by the Spanish, Italian and Amerindian ethnic groups.

Cracking the code of aldosterone synthase deficiency: bridging genetics and biochemistry: a case report.

Aldosterone synthase deficiency (ASD) is a rare autosomal recessive inherited disease with an overall clinical phenotype of failure to thrive, vomiting, severe dehydration, hyperkalemia, and hyponatremia. Mutations in the CYP11B2 gene encoding AS are responsible for the occurrence of ASD. Defects in CYP11B2 gene have only been reported in a limited number of cases worldwide. Due to this potential life-threatening risk, a comprehensive hormonal investigation followed by genetic confirmation is essential for the clinical management of offspring. We report a case of a newborn who was found to have persistent hyponatremia, hyperkalemia, low aldosterone level, raised renin levels, normal cortisol, and normal 17 hydroxyprogesterone level, suggesting the diagnosis of isolated ASD. Genetic report was suggestive of isolated ASD caused by a novel base pair deletion in exon 3, homozygous CYP11B2 variant (chr8:g.142915123_142915125del; depth: 124x d) (p.Lys175del; ENST00000323110.2). After initial steps of rehydration and salt restoration, the child was started on oral tablet fludrocortisone. The child responded well and showed a good gain in growth and development. We elaborate on the biochemical and genetic work-up performed and describe potential pitfalls in CYP11B2 sequencing due to its homology to CYP11B1.

Modulation of Haemostatic Balance in Combined von Willebrand Disease and Antithrombin Deficiency: A Comprehensive Family Study.

Maintaining the balance between procoagulant and anticoagulant factors is essential for effective haemostasis. Emerging evidence suggests a modulation of bleeding tendency by factors in the anticoagulant and fibrinolytic systems. This study investigates the clinical and laboratory characteristics of a family with combined von Willebrand disease (VWD) and antithrombin (AT) deficiency. The study focused on a 38-year-old female index patient (IP) with severe type 3 VWD and a history of bleeding disorders. Coagulation assays included VWF antigen, platelet-dependent VWF activity, factor VIII activity, thrombin generation assay (TGA) and AT activity. Molecular genetic analyses were conducted by a targeted DNA custom next generation sequencing (NGS) panel. The IP and one of her sisters suffered type 3 VWD. While the IP presents with a classical severe bleeding phenotype, the sister (II-2) exhibited less severe bleeding symptoms. Extended family members showed type 1 VWD with mild presentations. NGS revealed a homozygous deletion of exon 6 in the VWF gene in the IP and her sister (II-2). All other family members carry this genetic variant in a heterozygous state. Additionally, II-2 has a heterozygous variant in the SERPINC1 gene (c.133C>T, p.Arg45Trp). Both IP and II-2 carry a homozygous prothrombin G20210A variant. TGA results indicated reduced thrombin generation in severe VWD patients, with a pronounced thrombin burst in those with the AT and prothrombin G20210A variant. AT deficiency appears to modulate bleeding symptoms in severe VWD. This study emphasizes the importance of comprehensive genetic and phenotypic evaluation in managing complex coagulation disorders.

Analysis of exonic deletions in a large population study provides novel insights into NRXN1 pathology

The NRXN1 locus is a hotspot for non-recurrent copy number variants and exon-disrupting NRXN1 deletions have been associated with increased risk of neurodevelopmental disorders in case-control studies. However, corresponding population-based estimates of prevalence and disease-associated risk are currently lacking. Also, most studies have not differentiated between deletions affecting exons of different NRXN1 splice variants nor considered intronic deletions. We used the iPSYCH2015 case-cohort sample to obtain unbiased estimates of the prevalence of NRXN1 deletions and their associated risk of autism, schizophrenia, depression, and ADHD. Most exon-disrupting deletions affected exons specific to the alpha isoform, and almost half of the non-exonic deletions represented a previously reported segregating founder deletion. Carriage of exon-disrupting NRXN1 deletions was associated with a threefold and twofold increased risk of autism and ADHD, respectively, whereas no significantly increased risk of depression or schizophrenia was observed. Our results highlight the importance of using population-based samples in genetic association studies.

Plasmodium falciparum with pfhrp2 and pfhrp3 gene deletions in asymptomatic malaria infections in the Lake Victoria region, Kenya

Malaria rapid diagnostic tests (RDTs) targeting the Plasmodium falciparum histidine-rich protein 2 (PfHRP2) are widely used to diagnose P. falciparum infection. However, reports of P. falciparum strains lacking PfHRP2 and the structurally similar PfHRP3 have raised concerns about the utility and reliability of PfHRP2-based RDTs. This study investigated the presence of P. falciparum with pfhrp2 and/or pfhrp3 gene deletions among infected residents in the Lake Victoria region, Kenya. Four cross-sectional malaria, surveys were conducted in four sites (Suba South, Mfangano, Kibuogi, and Ngodhe) from September 2018 to January 2020. P. falciparum infections were detected using a PfHRP2-based RDT, microscopy, and PCR on 9120 finger-prick blood samples. Samples negative by RDT but positive by PCR were selected for PCR amplification of pfmsp1 and pfmsp2 to confirm the quality and quantity of P. falciparum DNA. Samples positive for both pfmsp1 and pfmsp2 were included for detection of deletions of exons 1 and 2 in pfhrp2 and pfhrp3 PCR. The multiplicity of infection (MOI) was determined as the higher allele count between pfmsp1 and pfmsp2. Logistic regression analysis was performed to analyze the association between pfhrp2 and/or pfhrp3 deletions and demographic and infection variables. Of the 445 RDT-negative and PCR-positive samples, 125 (28.1%) were analyzed for pfhrp2 and pfhrp3 deletions. Single pfhrp2 deletion, single pfhrp3 deletion, and pfhrp2/3 double deletions were detected in 13 (10.4%), 19 (15.2%), and 36 (28.8%) samples, respectively. Single pfhrp2 deletion was found in all sites while single pfhrp3 deletion was found in all sites except Kibuogi. The majority of samples with pfhrp2 and/or pfhrp3 deletions were submicroscopic (73.5%), asymptomatic (80.9%), and monoclonal (80.9%). Polyclonal infection was significantly (p = 0.022) associated with a lower odds of pfhrp2/3 double deletion, suggesting detection of intact pfhrp2/3 in mixed infections. We report the presence of P. falciparum with pfhrp2/pfhrp3 double deletions among asymptomatic and submicroscopic infections in Kenya. Our findings highlight the need for active monitoring of pfhrp2 and pfhrp3 deletions at the community level to improve malaria detection and control in the region.

Generation of a novel mouse model of nemaline myopathy due to recurrent NEB exon 55 deletion.

Biallelic pathogenic variants in the nebulin ( NEB ) gene lead to the congenital muscle disease nemaline myopathy. In-frame deletion of exon 55 (ΔExon55) is the most common disease-causing variant in NEB . Previously, a mouse model of Neb ΔExon55 was developed; however, it presented an uncharacteristically severe phenotype with a near complete reduction in Neb transcript expression that is not observed in NEB exon 55 patients. We identified by RNA sequencing that the cause of this unexpectedly severe presentation in mice is the generation of a pseudoexon containing two premature termination codons (and promoting nonsense mediated decay) at the Neb exon 55 deletion site. To prove that this is the cause of the loss of Neb transcript, and to generate a more faithful model of the human disease, we used CRISPR gene editing to remove the pseudoexon sequence and replace it with human intron 54 sequence containing a validated cas9 gRNA protospacer. The resulting "hmz" mice have a significant reduction in pseudoexon formation (93.6% reduction), and a re-introduction of stable Neb transcript expression. This new model has the characteristic features of nemaline myopathy at the physiological, histological, and molecular levels. Importantly, unlike the existing exon 55 deletion mice (which die by age 7 days), it survives beyond the first months and exhibits obvious signs of neuromuscular dysfunction. It thus provides a new, robust model for studying pathomechanisms and developing therapies for NEB related nemaline myopathy.

A new GRN variant in logopenic variant primary progressive aphasia: a case report and literature review

ABSTRACT The majority of genetic Primary progressive aphasia (PPA) patients harbor mutations in the granulin (GRN) gene. The present case showed impaired performances in single-word retrieval in spontaneous speech and naming, and repetition. Head MRI revealed marked lateral atrophy in the left parietal cortex. A diagnosis of logopenic variant PPA (lvPPA) was established. Genetic analysis showed a heterozygous 10-bp frameshift deletion in exon 4 of the GRN gene (NM_002087.4), leading to transformation of cysteine into alanine at amino acid 92 and creation of a premature stop codon at position 161. This patient represented a rare case of GRN-associated lvPPA. A new mutation site was detected in exon 4 of GRN gene.

Unveiling New Clinical and Genetic Insights in Ultra-Rare Intellectual Disability Phenotypes: A Study of a Turkish Cohort.

Intellectual disability (ID) is defined as a severe impairment in reasoning, learning, and problem-solving abilities along with adaptive behavior that occurs before the age of 18 years. The present study aimed to present the clinical and genetic data of a cohort of Turkish pediatric patients diagnosed with the ultrarare (which only up to 20 cases having been reported in the relevant literature thus far) ID phenotype. A total of 29 patients from 26 different families, who were diagnosed with ultrarare ID upon whole exome sequencing (WES) analysis, were included in the study. Of the patients included in the study, 18 (62%) were male and 11 (38%) were female. There was consanguinity between parents in 16 families (55%). With respect to the ID phenotype, three families had cases with a similar phenotype, while 23 families (88%) had sporadic cases. Upon molecular analysis, 28 different variations in 23 different genes were noted. Of the variations detected, 15 were missense, 6 nonsense, 4 frameshift, 2 splice-site, and 1 gross exonic deletion. Nine (32%) variations were novel among the detected variations. This study summarized the clinical and genetic features of 23 different ultrarare ID phenotypes by means of WES study, including copy number variations (CNVs) analysis. Novel clinical and genetic findings in the present study contribute to a better understanding of the genotypic and phenotypic spectrum. The effects of some rare variations on protein structure were revealed by means of in silico modeling. Newly described cases with ultrarare phenotypes help achieve a clearer description of the clinical and genetic manifestations of the syndromes and gain a better understanding of the molecular mechanisms.

Unveiling non-coding DMD variants: synergising RNA sequencing and DNA sequencing for enhanced molecular diagnosis

BackgroundPathogenic variants in the DMD gene are associated with dystrophinopathy including Duchenne and Becker muscular dystrophy (DMD/BMD). Targeted DMD gene, gene panels, exomes and genome sequencing have advanced genetic diagnostics,...

Abstract PR004: Brain penetrant allosteric EGFR inhibitors for NSCLC

Abstract Approximately 30-50% of Non-Small Cell Lung Cancer (NSCLC) patients already have CNS disease at time of diagnosis or else develop it during treatment, and there remains a need for better outcomes in these patients. The 3rd-generation covalent EGFR inhibitor osimertinib is an effective therapy for NSCLC patients, improving upon 1st-generation inhibitors gefitinib and erlotinib, and achieving enhanced brain penetration relative to those agents. However, the survival benefit relative to the 1st-generation inhibitors is observed primarily in patients with exon19 deletions rather than the L858R mutation. We developed a series of mutant-selective allosteric EGFR inhibitors that specifically target the L858R mutation (and subsequent resistance mutations), with high selectivity over wt EGFR and across the kinome. Early compounds including the isoindolinone JBJ-09-063 demonstrated good in vivo efficacy in mouse tumor models, despite limited bioavailability. Diversification and optimization of the chemistry, involving a scaffold hopping approach and the replacement of the thiazole amide with benzimidazole, delivered a set of compounds with promising potency and rodent PK. A subset of these achieved good brain exposure in mice and efficacy in an intracranial H1975 brain metastasis model. The mutant-selectivity and ability to co-bind with osimertinib makes an allosteric EGFR inhibitor an ideal partner for combination therapy, with the potential to deliver enhanced outcomes in L858R-driven NSCLC, especially for patients with CNS disease. Citation Format: David Scott, Courtney Cullis, Tyler Beyett, Frederic Feru, Thomas Gero, Krista Gipson, Praful Gokhalle, Nathanael Gray, David Heppner, Sampson Huang, Pasi Jänne, Sandeepraj Pusalkar, Michael Eck. Brain penetrant allosteric EGFR inhibitors for NSCLC [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Optimizing Therapeutic Efficacy and Tolerability through Cancer Chemistry; 2024 Dec 9-11; Toronto, Ontario, Canada. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(12_Suppl):Abstract nr PR004

Genetic analysis of children with nonsyndromic sensorineural hearing loss due to novel mutations/deletions of STRC bialleles

Objective: To investigate the clinical and genetic characteristics of nonsyndromic sensorineural hearing loss caused by STRC biallelic variation. Methods: A child with hearing impairment who was diagnosed at Gansu Provincial Maternal and Child Health Hospital on May 2022 and was selected as the research object. Peripheral blood of the child and her parents was collected, genomic DNA was extracted. IDT The xGen Exome Research Panel v2.0 whole exome capture chip was used to capture and sequence. Bioinformatics and clinical information analysis technology were used to analyze genetic data. The suspected pathogenic mutations were verified by quantitative polymerase chain reaction(QPCR)and Sanger sequencing. Results: The child had moderate hearing loss at about 1 year and 10 months, and now she is 3 years and 6 months, the hearing loss has not worsened. Whole exome sequencing(WES) testing revealed that the child carried the STRC gene with a deletion in EXON:1-29 and variants c.4561(exon24) _c.4562(exon24)insC, inherited from the mother and father, respectively. According to the relevant guidelines of the American Society for Medical Genetics and Genomics (ACMG), they were determined to be likely pathogenic variant and pathogenic variant. Conclusion: The discovery of c.4561(exon24) _c.4562(exon24)insC enriched the STRC variation spectrum, and provided a theoretical basis for the diagnosis and genetic counseling to the children.

Generation and characterization of zebrafish f9l mutant confirmed that f9l is f10 like gene.

This study aimed to create an f9l mutant zebrafish using clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) and characterize its coagulation properties to investigate its functional similarity to human FX and explore the potential synergy between f9l and f10. Three gRNAs targeting exon 8 encoded by the catalytic domain of the f9l gene were injected into 300 single-cell zebrafish embryos using CRISPR/Cas9 technology. DNA from the resulting adults was extracted from tail tips, and PCR was used to detect indels. The identified founder mutant was bred to homozygosity, and functional assays, kinetic Russel viper venom time, bleeding assay in adults, and venous laser injury on larvae were conducted to assess its hemostatic function. Additionally, f10 was knocked down in f9l homozygous embryos using f10 antisense morpholinos to study their interaction by monitoring its survival. DNA from 60 adults was screened for indels, resulting in a fish with a heritable complex mutation involving one insertion and two deletions in exon 8. The f9l homozygous mutants exhibited impaired F10 activity, mild bleeding after mechanical injury, and developmental deformities in early larval stages. The caudal vein thrombosis assay showed variable occlusion times, indicating a bleeding phenotype with incomplete penetrance. Knocking down f10 in f9l homozygous embryos resulted in 50% mortality within five dpf, compared to f9l homozygous embryos injected with control morpholinos. In summary, we generated f9l knockout and showed it is a paralog to f10. We also found a synergy between f9l and f10 genes, highlighting its importance in hemostasis.

Giant axonal neuropathy: A rare disease hidden in polyneuropathy

Background&amp; Objective: Giant axonal neuropathy (GAN) is a serious progressive neurodegenerative disease. The aim of this study is to evaluate the frequency and phenotypic-genotypic characteristics of GAN patients, which, like many rare diseases, is disguised under the name of polyneuropathy, and to present our experience. Methods: In this retrospective observational study, 105 pediatric patients with polyneuropathy were screened. Demographic characteristics and clinical diagnoses were reviewed. The mean age of the patients was 10.9 years (2-18), 59 were boys (56%) and 46 were girls (44%). GAN patients who were genetically diagnosed by single gene analysis were clinically evaluated in detail. Results: Regarding the etiology of polyneuropathy, 43% of patients had acquired and 57% had hereditary causes. Among hereditary cases, 29% had an unknown diagnosis, and 5% were diagnosed with GAN, presenting first with gait disturbance. These patients exhibited axonal sensorimotor polyneuropathy and diverse hair types (20% straight, 20% kinky, 40% curly, 20% slightly curly). Findings included carious teeth (40%), hyperplexia (20%), and apnea (20%). Disease progression included worsening scoliosis and limb deformities (pes cavus), with pathological cranial MRI findings. Literature identified 5 GAN patients with a homozygous deletion of GAN gene exon 2-5, classified as likely pathogenic (Class 4). Conclusion: This study highlights the frequency of GAN among undiagnosed polyneuropathies in childhood. Although the phenotype-genotype correlation for giant axonal neuropathy has not yet been determined, we hope that further studies in the field of molecular biology will increase the chances of a better quality of life.