NPJ Genomic Medicine最新文献

This study aims to characterize the clinical spectrum and genetic landscape of IRDs in Portugal. Multicentre, cross-sectional, cohort study comprising consecutive patients with a clinical diagnosis of IRD and available genetic results, enroled in the IRD-PT registry (retina.com.pt). Among the 1369 patients enroled from 1125 families, the most frequently observed phenotype was non-syndromic retinitis pigmentosa (40.8%). A genetically confirmed diagnosis was achieved in 72.3% of families. Consanguinity was observed in one-fifth of cases, contributing to a higher frequency of homozygous variants within this cohort. Disease-causing genotypes were distributed across 136 different genes, with ABCA4 (13.0%), EYS (10.0%) and USH2A (6.9%) being the most frequently mutated genes. Overall, these results from a nationwide cohort significantly advance our understanding of the clinical and genetic spectrum of IRDs in Portugal, laying the groundwork for future studies to identify patients eligible for targeted therapies and to describe the natural history of these diseases.

Nail-Patella syndrome (NPS) is a rare autosomal dominant condition due to haploinsufficiency of LMX1B, caused by loss-of-function variants affecting the coding sequence, or partial/whole deletions of the gene. In here, we describe two familial cases of NPS, carrying novel variants of the LMX1B 5'UTR region (-174C>T and -226G>A). To verify their pathogenic role, we carried out a functional characterization, both by reporter gene assays in heterologous systems and in patient's derived cells. We demonstrated that both variants impair LMX1B expression at post-transcriptional level. They introduce two upstream open reading frames (uORFs), out-of-frame with the main LMX1B coding sequence, generating transcripts detected by the non-sense mediated decay (NMD). We also demonstrated that the escape of the altered mRNA from NMD, if any, may lead to the synthesis of an aberrant LMX1B protein.

Turner syndrome (TS) presents with multiple karyotypes, including 45,X monosomy and variants such as isochromosomes and mosaicism, and is characterized by several co-morbidities, including metabolic conditions and autoimmunity. Here, we investigated the genomic landscapes across a range of karyotypes. We show that TS have a common autosomal methylome and transcriptome, despite distinct karyotypic variations. All TS individuals lacked the X chromosome p-arm, and XIST expression from the q-arm did not affect the autosomal transcriptome or methylome, highlighting the critical role of the missing p-arm with its pseudoautosomal region 1. Furthermore, we show increased levels of neutrophils and increased neutrophil activation. The increase in neutrophils was linked to TS clinical traits and to increased expression of the X-Y homologous gene TBL1X, suggesting a genetic basis, which may lead to neutrophil-driven inflammatory stress in TS. Identifying TS individuals with increased neutrophil activation could potentially mitigate the progression towards more severe metabolic issues.

Junctional epidermolysis bullosa (JEB) is characterized by mucocutaneous fragility. We enrolled 69 cases of recessive JEB, with 13.0% of these cases remained genetically undiagnosed following an initial exome sequencing. Among cases carried COL17A1 variants, this proportion can reach 31.6%. We employed genome sequencing to genetically diagnosis these cases. Four deep intronic variants (c.4156+117 G > A, c.2039-104 G > A and c.1267+237dupC in the COL17A1 gene and c.-38 + 2 T > C in the LAMB3 gene) were identified in six cases. The c.4156+117 G > A variant was found in three of the five cases, suggesting it may be a common deep intronic variant in Chinese JEB. Splicing analysis revealed that these variants caused splicing defect by inducing exon skipping, or pseudoexon insertion into the transcript in HaCaT cells, not in HEK293 cells. Our results emphasize the importance of selecting the right cell line for mRNA analysis.

Human height prediction based on genetic factors alone shows positive correlation, but predictors developed for one population perform less well when applied to population of different ancestries. In this study, we evaluated the utility of incorporating non-genetic factors in height predictors for the Han Chinese population in Taiwan. We analyzed data from 78,719 Taiwan Biobank (TWB) participants and 40,641 Taiwan Precision Medicine Initiative (TPMI) participants using genome-wide association study and multivariable linear regression least absolute shrinkage and selection operator (LASSO) methods to incorporate genetic and non-genetic factors for height prediction. Our findings establish that combining birth year (as a surrogate for nutritional status), age at measurement (to account for age-associated effects on height), and genetic profile data improves the accuracy of height prediction. This method enhances the correlation between predicted and actual height and significantly reduces the discrepancies between predicted and actual height in both males and females.

We investigated the effectiveness of exome sequencing (ES) in diagnosing ethnically diverse patients with rare genetic disorders. A total of 18,994 patients referred to a single reference laboratory for ES between 2020 and 2022 were studied for the diagnostic rate and factors influencing the diagnostic rate. The overall diagnostic rate was 31.8%. Dermatological disorders, skeletal disorders, and neurodevelopmental disorders disease categories, early age-of-onset, presence of consanguinity, and the presence of parental sequencing data were found to be correlated with a higher diagnostic rate. Nearly 68K variants were identified in our dataset at a higher frequency than that observed in gnomAD 4.0. Of these, 507 variants could be classified as likely benign, representing 0.04% of non-benign variants in ClinVar (507/1,433,904) and 0.20% of the non-benign ClinVar variants observed at least once in our cohort (507/276,777). The overall diagnostic rate is comparable to that observed in other large cohort studies with less diverse ethnic backgrounds.

Multigene panel tests (MGPTs) revolutionized the diagnosis of Lynch syndrome (LS), however noncoding pathogenic variants (PVs) can only be detected by complementary methods including whole genome sequencing (WGS). Here we present a DNA-, RNA- and tumor tissue-based WGS prioritization workflow for patients with a suspicion of LS where MGPT detected no LS-related PV. Among the 100 enrolled patients, MGPT detected 28 simple PVs and an additional 3 complex PVs. Among the 69 MGPT-negative patients, the lack of somatic MLH1 promoter methylation in a patient with a distinguished MLH1 allelic imbalance selected this sample for WGS. This returned a germline deep intronic MLH1 variant, with further functional studies confirming its' pathogenicity. Interestingly, all three complex PVs and the MLH1 deep intronic PV were found to be recurrent at our center. Our straightforward and cost-effective prioritization workflow can optimally include WGS in the genetic diagnosis of LS.

Immunocompromised patients struggle to adequately clear viral infections, offering the virus the opportunity to adapt to the immune system in the host. Here we present a case study of a patient undergoing allogeneic hematopoietic stem cell transplantation with a 521-day follow-up of a SARS-CoV-2 infection with the BF.7.21 variant. Virus samples from five time points were submitted to whole genome sequencing. Between the first detection of SARS-CoV-2 infection and its clearance, the patient's virus population acquired 34 amino acid substitutions and 8 deletions in coding regions. With 11 amino acid substitutions in the receptor binding domain of the virus' spike protein, substitutions were 15 times more abundant than expected for a random distribution in this highly functional region. Amongst them were the substitutions S:K417T, S:N440S, S:K444R, S:V445A, S:G446N, S:L452Q, S:N460K, and S:E484V at positions that are notorious for their resistance-mediating effects. The substitution patterns found indicate ongoing adaptive evolution.

Colorectal cancer (CRC) is one of the most common cancers worldwide. Lynch Syndrome (LS) is the most common form of hereditary CRC and it is caused by germline defects in the DNA-mismatch repair (MMR) pathway. It is of extreme importance for affected LS patients and their relatives to identify the germline causative alteration to provide intensified surveillance to those at risk and allow early diagnosis and cancer prevention. Current approaches for LS molecular diagnosis typically involve screening of the MMR genes by targeted gene-panel sequencing and rearrangement screening. We report the identification and characterization of a novel germline structural variant encompassing 48.757 kb, involving the 3'-ends of the MLH1 and LRRFIP2 genes, as the cause of LS in a family of Ecuador. Whole-genome sequencing and transcriptomics allowed the identification of the genomic rearrangement and highlights the importance of the use of these additional approaches to achieve a comprehensive molecular diagnosis in some LS patients.

Maturation of αβ lineage T cells in the thymus relies on the formation and cell surface expression of a pre-T cell receptor (TCR) complex, composed of TCRβ chain and pre-TCRα (pTCRα) chain heterodimers, giving rise to a diverse T cell repertoire. Genetic aberrations in key molecules involved in T cell development lead to profound T cell immunodeficiency. Definitive genetic diagnosis guides treatment choices and counseling. In this study, we describe the role of whole genome sequencing (WGS) in providing a definitive diagnosis for a child with T cell deficiency, where targeted panel sequencing of SCID genes and whole exome sequencing had failed. A novel homozygous 8kb deletion in PTCRA, encoding pTCRα, was identified. To date, use of WGS remains restricted and for many geographical regions, is clinically unavailable.