Human molecular genetics最新文献

To explore the genetic underpinnings of glaucoma endophenotypes influenced by mechanisms other than intraocular pressure (IOP), this study employs genomic structural equation modelling (GenomicSEM) and utilises summary statistics from Genome-Wide Association Studies (GWAS) to examine endophenotypes associated with non-IOP mechanisms. We investigated the genetic relationships among primary open-angle glaucoma (POAG) and key endophenotypes: IOP, normal tension glaucoma (NTG), vertical cup disc ratio (VCDR), total macular thickness, ganglion cell-inner plexiform layer (GCIPL), and retinal nerve fiber layer (RNFL), through exploratory factorial analysis (EFA) and confirmatory factorial analyses (CFA). GWAS-by-subtraction approach was employed to explore the genetic architecture of non-IOP components. Post-GWAS analyses implemented in Functional Mapping and Annotation (FUMA) and Multi-marker Analysis of Genomic Annotation (MAGMA) were conducted to identify non-IOP genes and pathways. The EFA revealed that 60% of the cumulative variance was explained by two latent factors (F1, F2). F1 included VCDR, POAG, NTG, and IOP, while F2 comprised RNFL, GCIPL, macular thickness, and VCDR. Significant associations between F2 and macular thickness and RNFL persisted after subtracting IOP. MAGMA analysis identified IOP-independent pathways for macular thickness and VCDR, primarily involving nerve and vascular pathways. Despite lower IOP levels in NTG patients, GWAS-by-subtraction revealed both significant IOP and non-IOP components for NTG. This research highlights the significance of non-IOP mechanisms in the development of glaucoma. Targeting these mechanisms could pave the way for developing novel treatments that extend beyond conventional IOP-based therapies. Further research is needed to explore non-IOP pathways in NTG and validate these findings across diverse populations.

Background: Hereditary breast cancer, primarily linked to pathogenic BRCA1 and BRCA2 mutations, accounts for 5%-10% of all breast cancer cases in the United States. Despite national guidelines recommending genetic testing for individuals at elevated hereditary risk, uptake remains disproportionately low among African American and Hispanic/Latina women. Despite elevated risk in Black women data on genetic testing uptake in St. Louis is absent.

Objective: This systematic review aimed to address three research questions: (1) Are there racial and ethnic disparities in the utilization of BRCA genetic testing in Saint Louis? (2) What individual, provider, and systemic factors influence testing uptake among diverse populations? (3) What policy-level interventions are feasible and effective to improve BRCA testing rates in the city?

Methods: A systematic search of MEDLINE, EMBASE, APA PsycInfo, CINAHL Plus, Scopus, and Web of Science yielded 264 unique records. Twenty-five peer-reviewed studies published between 1996 and 2024 were included after applying inclusion criteria and quality appraisal. The studies span quantitative, qualitative, and mixed methods research on high-risk populations.

Results: BRCA awareness among African American women was significantly lower (12%-32%) than among White women (65%-75%). Fear of results (54%), mistrust, and concern over genetic discrimination (60%) were major barriers. Referral disparities were also stark-African American women were 50% less likely to receive provider referrals. Only 5% of genetic counselors identified as Black or Hispanic.

Conclusions: No studies specifically examined BRCA testing disparities in Saint Louis. Findings from similar Midwestern cities suggest urgent need for locally informed, equity-focused interventions.

Syndromic forms of craniosynostosis occur as a result of dysregulation of various molecular signaling cascades. In humans, a specific gain-of-function mutation (W566R) in PDGFRB causes a distinctive overgrowth syndrome (OMIM # 616592). Affected individuals exhibit distinctive facial features and craniosynostosis. Using CRISPR/Cas9 gene editing, we generated a mouse model carrying the same pathogenic variant of PDGFRB. The Pdgfrb+/W565R mice exhibited craniosynostosis with skull-base malformation: thus, we successfully recapitulated the human disease phenotype. In humans, haploinsufficiency of RUNX2, a critical transcription factor in osteogenesis, results in defects of the skull and clavicles due to insufficient membranous ossification. Such phenotypes have been well reproduced in Runx2+/- mice. To delineate the molecular mechanisms underlying the development of Pdgfrb-related craniosynostosis, we crossed the Pdgfrb+/W565R mice with Runx2+/- mice. It is noteworthy that the double- mutant mice, i.e. Pdgfrb+/W565R  Runx2+/- mice, exhibited near complete restoration of the cranial sutures and skull base. The present observation provides in vivo evidence that overactivation of Pdgfrb signaling leads to craniosynostosis through the effect of Runx2. The phenotypic reversal of the cranial structures suggests that modification of the Pdgfrb-Runx2 signaling cascade might offer a novel therapeutic opportunity for craniosynostosis.

Fragile X Syndrome is the most prevalent known genetic cause of intellectual disability (ID), affecting around 1 in 4 000 individuals, and is also highly associated with autism spectrum disorder (ASD). Humans with the disorder and animal models display sleep and metabolic abnormalities. Given growing evidence of links between sleep and metabolism, we sought to determine if metabolic abnormalities underlie sleep deficits in mice lacking the Fragile X messenger ribonucleoprotein 1 (FMR1) gene. We found that metformin, a drug that targets metabolic pathways and has been shown to alleviate other symptoms in FXS, did not rescue sleep in mutant mice. Instead, metformin enhanced activity of Fmr1 knockout (KO) mice. As a way of exaggerating possible metabolic phenotypes, we treated mice with a high fat diet (HFD) and found that although this disrupted the sleep pattern in controls, it did not impact the sleep phenotype in Fmr1 KOs. Increased sleep during the dark phase, caused by HFD in wild type animals, was alleviated by metformin treatment. Metformin also decreased weight gain of wild type animals on a HFD, but the effect was delayed in Fmr1 KO mice. Fmr1 KO mice with or without metformin treatment displayed hyperphagia on a HFD, yet did not show higher weight gain than wild type. And, surprisingly, their glucose tolerance was equivalent to that of wild type mice on metformin. We suggest that Fmr1 KO mice are better able to metabolize fat and so are relatively resistant to its negative effects on sleep and metabolism.

N-lactoyl-amino acids (Lac-AA) are emerging as important metabolites with diverse physiological roles. This study integrates metabolomics and genomics to investigate the genetic determinants and clinical relevance of three Lac-AA: N-Lactoyl phenylalanine (Lac-Phe), N-Lactoyl tyrosine (Lac-Tyr), and N-Lactoyl valine (Lac-Tyr). We conducted a metabolome-wide association study (mGWAS) on 2811 participants followed by a phenome-wide association study (PheWAS) and pathway enrichment analysis. Our mGWAS revealed modest genetic contributions to Lac-AA levels, with genome-wide significant loci identified for Lac-Tyr and Lac-Val, but not for Lac-Phe. PheWAS analysis linked these genetic variants to key clinical traits, including white blood cell count, platelet count, and glucose levels. Pathway enrichment highlighted the involvement of Lac-AA in immune-metabolic crosstalk, particularly in inflammation and energy metabolism. These findings suggest that Lac-AA levels are primarily influenced by dynamic metabolic or inflammatory states rather than fixed genetic factors. Our results underscore the potential of Lac-AA as metabolic sensors and biomarkers at the intersection of cellular energy states and systemic inflammation, opening new avenues for research in metabolic and inflammatory disorders.

Antisense oligonucleotides (AONs) are small pieces of chemically modified DNA or RNA that bind to RNA in a sequence-specific manner based on Watson-Crick base-pairing. Splice-switching AONs are designed to modulate pre-mRNA splicing, thereby for instance restoring protein expression or modifying the eventual protein to restore its function or reduce its toxicity. Given the current lack of in silico methods that adequately predict off-target splicing events, assessment of off-target effects of AONs in human cells using RNAseq could be a promising approach. The identification and prioritization of potential off-target effects for validation and further investigation into the biological relevance would contribute to the development of safe and effective AONs. In this study, we used three different splice-switching AONs targeting three different human transcripts to study their transcriptome-wide, hybridization-dependent off-target effects with short read RNAseq. Using the computational tools rMATS and Whippet, we identified differential splicing events of which only a minority could be explained by hybridization, illustrating the difficulty of predicting off-target effects based on sequence homology. The main splicing events could all be validated with RT-PCR. Furthermore, from the three AONs studied, one AON induced considerably more changes in gene expression and splicing compared to the two other AONs assessed, which was confirmed in a validation experiment. Our study demonstrates that interpretation of short read RNAseq data to determine off-target effects is challenging. Nonetheless, valuable results can be obtained as it allows the comparison of toxicity between different AONs within an experiment and identification of AON-specific off-target profiles.

Congenital myasthenic syndromes (CMS) arise from mutations to proteins involved in neuromuscular junction (NMJ) development, maintenance, and neurotransmission. To date, mutations in more than 35 genes have been linked to CMS development. Glutamine fructose-6-phosphate transaminase 1 (GFPT1/Gfpt1) serves as the rate-limiting enzyme of the hexosamine biosynthetic pathway (HBP), producing the byproduct (UDP-GlcNAc) necessary for protein glycosylation. Gfpt1-deficient models have impaired protein glycosylation, impacting key proteins at the NMJ. The Leloir pathway is a galactose metabolizing pathway which produces UDP-GalNAc as its final product. The enzyme UDP-GalNAc Epimerase (GALE) can also convert excess UDP-GalNAc into UDP-GlcNAc, the byproduct of the HBP. We hypothesized that treatment with galactose both in vitro and in vivo in Gfpt1-deficient models would rescue impaired protein O-GlcNAcylation and reverse the glycosylation status of key NMJ-associated proteins. We show that galactose treatment in vitro activated the Leloir pathway and rescued protein O-GlcNAcylation in Gfpt1-deficient C2C12 myoblasts. In addition, we demonstrated that galactose therapy rescued neuromuscular deficits, improved muscle fatigue and restored NMJ morphology in a skeletal muscle-specific Gfpt1 knockout mouse model. Lastly, we showed that galactose treatment rescued protein O-GlcNAcylation in skeletal muscle, preserving the glycosylation status of the delta (δ) subunit of the acetylcholine receptor (AChRδ). Taken together, we suggest that galactose supplementation can be further explored as a therapy for GFPT1-CMS patients.

β-propeller protein-associated neurodegeneration (BPAN) is characterized by global developmental delay, intellectual disability, and epileptic encephalopathies in infancy or early childhood caused by WDR45/WIPI4 gene mutations. WDR45 depletion disrupted autophagy, leading to iron accumulation in the brain and contributing to neuronal apoptosis. The impact on neuron performance remains unknown. Our previous study established the iPSC cell line derived from a girl patient with a de novo variant c.344 + 5G > T in WDR45 (FDHPIi001). This study demonstrated that this intron 6 mutation impairs RNA splicing, resulting in a 28 bp insertion and nonsense-mediated mRNA decay (NMD) of truncated WDR45. Upon differentiating the iPSCs into dopaminergic neurons, we observed significantly shorter neuronal axons using high-intensity imaging analysis. Additionally, there was significant ferritin accumulation in the induced neurons but not in the iPSCs from the same patient. This research has elucidated the pathogenicity of a non-canonical splice site mutation in WDR45 and has provided deeper insights into the pathologies of neurodegenerative diseases caused by WDR45 defects.

Co-occurrence of double heterozygosity in TARDBP and C9ORF72 is exceedingly rare in amyotrophic lateral sclerosis. While TARDBP mutations and C9ORF72 hexanucleotide repeat expansions have each been independently implicated in disease pathogenesis, their combined effect on disease progression and neuropathology remains unclear. We present the first study documenting a patient harboring both a TARDBP mutation and a C9ORF72 expansion, with comprehensive postmortem data available, to elucidate any additive or synergistic effects on disease course and pathological burden. Detailed clinical assessments tracked the patient's progression, and neuropathological examination was performed postmortem. The presence and extent of TDP-43 pathology and other hallmark features were evaluated and compared to known patterns in carriers of isolated C9ORF72 mutations. The patient's clinical trajectory and pathological findings did not show evidence of a more aggressive disease course or heightened pathological burden attributable to the additional TARDBP mutation. Instead, the disease manifested in a manner consistent with other C9ORF72 carriers, suggesting that double heterozygosity do not necessarily exacerbate ALS pathology.

Leber's hereditary optic neuropathy (LHON) is characterized by painless and rapidly progressive central vision loss, caused by various mutations in mitochondrial DNA, leading to a high genetic and phenotypic heterogeneity. Currently, the only approved therapy is idebenone, a CoQ10 synthetic analogue, that improved visual acuity in some LHON patients; however, results are highly variable due its dependency on functional NAD(P)H oxidoreductase I (NQO1) protein levels, thus limiting broader applicability. Targeting the biochemical respiratory chain defect and mitigating reactive oxygen species emission using alternative treatments which act independent of NQO1 protein content, represent a promising therapeutic strategy for all LHON patients. Here, we first characterized mitochondrial biology of three distinct LHON mutations in patient-derived fibroblasts and evaluated the effects of a nutraceutical combination treatment in addressing these shared pathophysiological mechanisms. We identified a range of mitochondrial characteristics common among various LHON mutations, including higher ROS levels, altered autophagy programming, and reduced mitochondrial bioenergetics. Repeated antioxidant and creatine-based treatment (ACT) conferred a favorable stress-resistant phenotype in LHON cells, which was similar to, and in some cases superior to, the effects observed with idebenone treatment, irrespective of NQO1 protein expression. This phenotype was associated with enhanced mitochondrial biology, as evidenced by reduced reactive oxygen species levels, increased cellular respiration, and correction of autophagic flux. Overall, our findings reveal both common and divergent mitochondrial phenotypes among LHON-related mutations and highlight the potential of accessible multi-ingredient nutraceutical interventions that could benefit all LHON patients.