RESUMEN
One of the main causes of cancer-related mortality for women worldwide is breast cancer (BC). The XRCC2 gene, essential for DNA repair, has been implicated in cancer susceptibility. This study aims to evaluate the association between XRCC2 and BC risk. The study was conducted at Zheen International Hospital in Erbil, Iraq, between 2021 and 2024 with a total of 88 samples, including 44 paired normal and cancer tissue samples. Mutation analysis was performed using Next-Generation Sequencing, coupled with in silico tools for variant impact prediction. Expression levels were assessed through RT-PCR, and methylation status was determined using methylation-sensitive restriction enzyme digestion PCR. The study identified seven inherited germline variants in the XRCC2 gene, with five of these mutations being Uncertain Significance, one being Likely Pathogenic, and one being Likely benign. RNA purity was found high with mean A260/280 ratios of 1.986 ± 0.097 in normal (N) and 1.963 ± 0.092 in tumor (T) samples. Tumor samples exhibited a higher RNA concentration (78.56 ± 40.87 ng/µL) than normal samples (71.44 ± 40.79 ng/µL). XRCC2 gene expression was significantly upregulated in tumor tissue, with marked increases in patients aged 40-55 and >56 years and in higher cancer grades (II and III) and invasive ductal carcinoma (p-values ranging from <0.0001 to 0.0392). DNA methylation rates in tumor tissues were low (7%), suggesting limited regulation by methylation. The study suggests that XRCC2 can be classified as an oncogene and that its structural investigation by targeted NGS and expression evaluation can be used as a potential biomarker in BC.
Asunto(s)
Neoplasias de la Mama , Metilación de ADN , Proteínas de Unión al ADN , Multiómica , Adulto , Femenino , Humanos , Persona de Mediana Edad , Neoplasias de la Mama/genética , Neoplasias de la Mama/patología , Metilación de ADN/genética , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Epigenómica/métodos , Regulación Neoplásica de la Expresión Génica , Predisposición Genética a la Enfermedad , Genómica/métodos , Multiómica/métodos , Transcriptoma/genéticaRESUMEN
BACKGROUND: The Triggering Receptor Expressed on Myeloid Cells 2 protein (TREM2) plays a crucial role in various biological processes, including osteoclast differentiation, and disease-associated microglia (DAM) activation to regulate neuroinflammation, and phagocytosis in the brain. Genetic variations in TREM2 are implicated in neurodegenerative disorders, such as Nasu-hakola disease (NHD), characterized by bone lesions, neuropsychiatric disorders, and early-onset dementia. METHODS: We studied 3 siblings with suspected NHD. Whole-exome sequencing was conducted on the proband to identify the possible genetic cause(s) and by Sanger sequencing to validate the identified variants in the two other affected siblings, a healthy sister, and the parents. RESULTS: We identified a novel homozygous deletion (c.549del; p.(Leu184Serfs*5)) in TREM2. Our literature review reveals 16 TREM2 mutations causing early-onset dementia and bone lesions. CONCLUSION: These findings, alongside previous research, elucidate the clinical spectrum of TREM2-related diseases, aiding accurate diagnosis and patient care. This knowledge is vital for understanding TREM2-dependent DAM and its involvement in the pathogenesis of neurodevelopmental disorders which can help to develop targeted therapies and improve outcomes for TREM2-affected individuals.
Asunto(s)
Homocigoto , Lipodistrofia , Glicoproteínas de Membrana , Osteocondrodisplasias , Receptores Inmunológicos , Hermanos , Panencefalitis Esclerosante Subaguda , Femenino , Humanos , Consanguinidad , Lipodistrofia/genética , Lipodistrofia/patología , Glicoproteínas de Membrana/genética , Osteocondrodisplasias/genética , Osteocondrodisplasias/patología , Linaje , Receptores Inmunológicos/genética , Panencefalitis Esclerosante Subaguda/genética , Panencefalitis Esclerosante Subaguda/patologíaRESUMEN
PURPOSE: We sought to describe a disorder clinically mimicking cystic fibrosis (CF) and to elucidate its genetic cause. METHODS: Exome/genome sequencing and human phenotype ontology data of nearly 40 000 patients from our Bio/Databank were analysed. RNA sequencing of samples from the nasal mucosa from patients, carriers and controls followed by transcriptome analysis was performed. RESULTS: We identified 13 patients from 9 families with a CF-like phenotype consisting of recurrent lower respiratory infections (13/13), failure to thrive (13/13) and chronic diarrhoea (8/13), with high morbidity and mortality. All patients had biallelic variants in AGR2, (1) two splice-site variants, (2) gene deletion and (3) three missense variants. We confirmed aberrant AGR2 transcripts caused by an intronic variant and complete absence of AGR2 transcripts caused by the large gene deletion, resulting in loss of function (LoF). Furthermore, transcriptome analysis identified significant downregulation of components of the mucociliary machinery (intraciliary transport, cilium organisation), as well as upregulation of immune processes. CONCLUSION: We describe a previously unrecognised autosomal recessive disorder caused by AGR2 variants. AGR2-related disease should be considered as a differential diagnosis in patients presenting a CF-like phenotype. This has implications for the molecular diagnosis and management of these patients. AGR2 LoF is likely the disease mechanism, with consequent impairment of the mucociliary defence machinery. Future studies should aim to establish a better understanding of the disease pathophysiology and to identify potential drug targets.
Asunto(s)
Fibrosis Quística , Mucoproteínas/genética , Proteínas Oncogénicas/genética , Fibrosis Quística/diagnóstico , Fibrosis Quística/genética , Regulador de Conductancia de Transmembrana de Fibrosis Quística/genética , Exoma , Humanos , Mutación , FenotipoRESUMEN
Human C2orf69 is an evolutionarily conserved gene whose function is unknown. Here, we report eight unrelated families from which 20 children presented with a fatal syndrome consisting of severe autoinflammation and progredient leukoencephalopathy with recurrent seizures; 12 of these subjects, whose DNA was available, segregated homozygous loss-of-function C2orf69 variants. C2ORF69 bears homology to esterase enzymes, and orthologs can be found in most eukaryotic genomes, including that of unicellular phytoplankton. We found that endogenous C2ORF69 (1) is loosely bound to mitochondria, (2) affects mitochondrial membrane potential and oxidative respiration in cultured neurons, and (3) controls the levels of the glycogen branching enzyme 1 (GBE1) consistent with a glycogen-storage-associated mitochondriopathy. We show that CRISPR-Cas9-mediated inactivation of zebrafish C2orf69 results in lethality by 8 months of age due to spontaneous epileptic seizures, which is preceded by persistent brain inflammation. Collectively, our results delineate an autoinflammatory Mendelian disorder of C2orf69 deficiency that disrupts the development/homeostasis of the immune and central nervous systems.
Asunto(s)
Encefalitis/genética , Enfermedades Mitocondriales/genética , Animales , Evolución Biológica , Sistemas CRISPR-Cas , Línea Celular , Encefalitis/mortalidad , Femenino , Genes Recesivos , Glucógeno/metabolismo , Humanos , Inflamación/genética , Masculino , Proteínas de la Membrana/genética , Enfermedades Mitocondriales/mortalidad , Linaje , Convulsiones/genética , Convulsiones/mortalidad , Pez Cebra/genéticaRESUMEN
Mutations in CLN3 (OMIM: 607042) are associated with juvenile neuronal ceroid lipofuscinoses (JNCL)-a rare neurodegenerative disease with early retinal degeneration and progressive neurologic deterioration. The study aimed to determine the underlying genetic factors justifying the NCL phenotype in a large Iraqi consanguineous family. Four affected individuals with an initial diagnosis of NCL were recruited. By doing neuroimaging and also pertinent clinical examinations, e.g. fundus examination, due to heterogeneity of neurodevelopmental disorders, the proband was subjected to the paired-end whole-exome sequencing to identify underlying genetic factors. The candidate variant was also confirmed by Sanger sequencing. Various in silico predictions were used to show the pathogenicity of the variant. This study revealed a novel homozygous frameshift variant-NM_000086.2: c.1127del; p.(Leu376Argfs*15)-in the exon 14 of the CLN3 gene as the most likely disease-causing variant. Three out of 4 patients showed bilateral vision loss (< 7 years) and retinal degeneration with macular changes in both eyes. Electroencephalography demonstrated the loss of normal posterior alpha rhythm and also low amplitude multifocal slow waves. Brain magnetic resonance imaging of the patients with a high degree of deterioration showed mild cerebral and cerebellar cortical atrophy, mild ventriculomegaly, thinning of the corpus callosum and vermis, and non-specific periventricular white matter signal changes in the occipital area. The novel biallelic deletion variant of CLN3 was identified that most probably led to JNCL with variable expressivity of the phenotype. This study also expanded our understanding of the clinical and genetic spectrum of JNCL.