Pathogenic variants in IMPG1 cause autosomal dominant and autosomal recessive retinitis pigmentosa

2020 ◽  
pp. jmedgenet-2020-107150
Author(s):  
Guillaume Olivier ◽  
Marta Corton ◽  
Daniela Intartaglia ◽  
Sanne K Verbakel ◽  
Panagiotis I Sergouniotis ◽  
...  
Keyword(s):  
Retinitis Pigmentosa ◽  
Exome Sequencing ◽  
Autosomal Dominant ◽  
Macular Dystrophy ◽  
Common Disease ◽  
Medaka Fish ◽  
Panel Testing ◽  
Pathogenic Variants ◽  
Gene Panel Testing

BackgroundInherited retinal disorders are a clinically and genetically heterogeneous group of conditions and a major cause of visual impairment. Common disease subtypes include vitelliform macular dystrophy (VMD) and retinitis pigmentosa (RP). Despite the identification of over 90 genes associated with RP, conventional genetic testing fails to detect a molecular diagnosis in about one third of patients with RP.MethodsExome sequencing was carried out for identifying the disease-causing gene in a family with autosomal dominant RP. Gene panel testing and exome sequencing were performed in 596 RP and VMD families to identified additional IMPG1 variants. In vivo analysis in the medaka fish system by knockdown assays was performed to screen IMPG1 possible pathogenic role.ResultsExome sequencing of a family with RP revealed a splice variant in IMPG1. Subsequently, the same variant was identified in individuals from two families with either RP or VMD. A retrospective study of patients with RP or VMD revealed eight additional families with different missense or nonsense variants in IMPG1. In addition, the clinical diagnosis of the IMPG1 retinopathy-associated variant, originally described as benign concentric annular macular dystrophy, was also revised to RP with early macular involvement. Using morpholino-mediated ablation of Impg1 and its paralog Impg2 in medaka fish, we confirmed a phenotype consistent with that observed in the families, including a decreased length of rod and cone photoreceptor outer segments.ConclusionThis study discusses a previously unreported association between monoallelic or biallelic IMPG1 variants and RP. Notably, similar observations have been reported for IMPG2.

scholarly journals Extended gene panel testing in lobular breast cancer

2021 ◽  
Author(s):  
Elke M. van Veen ◽  
D. Gareth Evans ◽  
Elaine F. Harkness ◽  
Helen J. Byers ◽  
Jamie M. Ellingford ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Genetic Testing ◽  
Detection Rate ◽  
Gene Panel ◽  
Lobular Breast Cancer ◽  
Germline Variants ◽  
Panel Testing ◽  
Pathogenic Variants ◽  
Gene Panel Testing ◽  
Increased Risk

AbstractPurpose: Lobular breast cancer (LBC) accounts for ~ 15% of breast cancer. Here, we studied the frequency of pathogenic germline variants (PGVs) in an extended panel of genes in women affected with LBC. Methods: 302 women with LBC and 1567 without breast cancer were tested for BRCA1/2 PGVs. A subset of 134 LBC affected women who tested negative for BRCA1/2 PGVs underwent extended screening, including: ATM, CDH1, CHEK2, NBN, PALB2, PTEN, RAD50, RAD51D, and TP53.Results: 35 PGVs were identified in the group with LBC, of which 22 were in BRCA1/2. Ten actionable PGVs were identified in additional genes (ATM(4), CDH1(1), CHEK2(1), PALB2(2) and TP53(2)). Overall, PGVs in three genes conferred a significant increased risk for LBC. Odds ratios (ORs) were: BRCA1: OR = 13.17 (95%CI 2.83–66.38; P = 0.0017), BRCA2: OR = 10.33 (95%CI 4.58–23.95; P < 0.0001); and ATM: OR = 8.01 (95%CI 2.52–29.92; P = 0.0053). We did not detect an increased risk of LBC for PALB2, CDH1 or CHEK2. Conclusion: The overall PGV detection rate was 11.59%, with similar rates of BRCA1/2 (7.28%) PGVs as for other actionable PGVs (7.46%), indicating a benefit for extended panel genetic testing in LBC. We also report a previously unrecognised association of pathogenic variants in ATM with LBC.

scholarly journals Mirtron-mediated RNA knockdown/replacement therapy for the treatment of dominant retinitis pigmentosa

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Harry O. Orlans ◽  
Michelle E. McClements ◽  
Alun R. Barnard ◽  
Cristina Martinez-Fernandez de la Camara ◽  
Robert E. MacLaren
Keyword(s):  
Retinitis Pigmentosa ◽  
Autosomal Dominant ◽  
Gene Mutations ◽  
Adeno Associated Virus ◽  
Treatment Development ◽  
Common Cause ◽  
Toxic Protein ◽  
Rna Knockdown

AbstractRhodopsin (RHO) gene mutations are a common cause of autosomal dominant retinitis pigmentosa (ADRP). The need to suppress toxic protein expression together with mutational heterogeneity pose challenges for treatment development. Mirtrons are atypical RNA interference effectors that are spliced from transcripts as short introns. Here, we develop a novel mirtron-based knockdown/replacement gene therapy for the mutation-independent treatment of RHO-related ADRP, and demonstrate efficacy in a relevant mammalian model. Splicing and potency of rhodopsin-targeting candidate mirtrons are initially determined, and a mirtron-resistant codon-modified version of the rhodopsin coding sequence is validated in vitro. These elements are then combined within a single adeno-associated virus (AAV) and delivered subretinally in a RhoP23H knock-in mouse model of ADRP. This results in significant mouse-to-human rhodopsin RNA replacement and is associated with a slowing of retinal degeneration. This provides proof of principle that synthetic mirtrons delivered by AAV are capable of reducing disease severity in vivo.

scholarly journals 167P Role of the multi-gene panel testing for detection of pathogenic variants in patients with hereditary bilateral breast cancer

2021 ◽  
Vol 32 ◽  
pp. S432-S433
Author(s):  
C. Filorizzo ◽  
D. Fanale ◽  
L. Incorvaia ◽  
N. Barraco ◽  
M. Bono ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Bilateral Breast Cancer ◽  
Gene Panel ◽  
Panel Testing ◽  
Pathogenic Variants ◽  
Gene Panel Testing

scholarly journals Expanding the search for germline pathogenic variants for breast cancer. How far should we go and how high should we jump? The missed opportunity!

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Hikmat Abdel-Razeq
Keyword(s):  
Breast Cancer ◽  
Brca1 And Brca2 ◽  
Healthy Women ◽  
Panel Testing ◽  
Pathogenic Variants ◽  
Gene Panel Testing ◽  
History Of ◽  
Risk Reducing ◽  
Current Guidelines ◽  
Missed Opportunity

Since the identification of BRCA1 and BRCA2 genes 3 decades ago, genetic testing and genetic counseling have become an integral part of routine clinical practice. The risk of breast cancer among carriers of germline pathogenic variants, like BRCA1 and BRCA2, is well established. Risk-reducing interventions, including bilateral mastectomies and salpingo-oophorectomies are both effective and have become more acceptable. Many researchers and professional societies view current guidelines as restrictive and may miss many at-risk women, and are calling to expand testing to include all patients with breast cancer, regardless of their personal or family history of cancer, while others are calling for wider adoption to even include all healthy women at age 30 or older. This review will address expanding testing in two directions; horizontally to include more patients, and even healthy women, and vertically to include more genes using next-generation sequencing-based multi-gene panel testing.

Cardiovascular genetics: the role of genetic testing in diagnosis and management of patients with hypertrophic cardiomyopathy

Heart ◽  
2020 ◽  
pp. heartjnl-2020-316798
Author(s):  
Monica Ahluwalia ◽  
Carolyn Y Ho
Keyword(s):  
At Risk ◽  
Clinical Practice ◽  
Genetic Testing ◽  
Hypertrophic Cardiomyopathy ◽  
Clinical Manifestations ◽  
Left Ventricular ◽  
Family Management ◽  
Panel Testing ◽  
Pathogenic Variants ◽  
Gene Panel Testing

Genetic testing in hypertrophic cardiomyopathy (HCM) is a valuable tool to manage patients and their families. Genetic testing can help inform diagnosis and differentiate HCM from other disorders that also result in increased left ventricular wall thickness, thereby directly impacting treatment. Moreover, genetic testing can definitively identify at-risk relatives and focus family management. Pathogenic variants in sarcomere and sarcomere-related genes have been implicated in causing HCM, and targeted gene panel testing is recommended for patients once a clinical diagnosis has been established. If a pathogenic or likely pathogenic variant is identified in a patient with HCM, predictive genetic testing is recommended for their at-risk relatives to determine who is at risk and to guide longitudinal screening and risk stratification. However, there are important challenges and considerations to implementing genetic testing in clinical practice. Genetic testing results can have psychological and other implications for patients and their families, emphasising the importance of genetic counselling before and after genetic testing. Determining the clinical relevance of genetic testing results is also complex and requires expertise in understanding of human genetic variation and clinical manifestations of the disease. In this review, we discuss the genetics of HCM and how to integrate genetic testing in clinical practice.

scholarly journals Novel mutations in the 3-box motif of the BACK domain of KLHL7 associated with nonsyndromic autosomal dominant retinitis pigmentosa

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Jin Kyun Oh ◽  
Jose Ronaldo Lima de Carvalho ◽  
Young Joo Sun ◽  
Sara Ragi ◽  
Jing Yang ◽  
...  
Keyword(s):  
Retinitis Pigmentosa ◽  
Autosomal Dominant ◽  
Fundus Autofluorescence ◽  
Retinal Dystrophy ◽  
Protein Modeling ◽  
Fundus Photography ◽  
Imaging Biomarkers ◽  
Loss Of Function ◽  
Gene Panel Testing ◽  
Sd Oct

Abstract Background Mutations in the Kelch-like protein 7 (KLHL7) represent a recently described and, to date, poorly characterized etiology of inherited retinal dystrophy. Dominant mutations in KLHL7 are a cause of isolated, non-syndromic retinitis pigmentosa (RP). In contrast, recessive loss-of-function mutations are known to cause Crisponi or Bohring-Opitz like cold induced sweating syndrome-3 (BOS-3). In this study, the phenotype and progression of five unrelated patients with KLHL7 mediated autosomal dominant RP (adRP) are characterized. Clinical evaluation of these patients involved a complete ophthalmic exam, full-field electroretinography (ffERG), and imaging, including fundus photography, spectral domain optical coherence tomography (SD-OCT), short wavelength fundus autofluorescence (SW-AF), and near-infrared fundus autofluorescence (NIR-AF). Molecular diagnoses were performed using whole-exome sequencing or gene panel testing. Disease progression was monitored in three patients with available data for a mean follow up time of 4.5 ± 2.9 years. Protein modeling was performed for all variants found in this study in addition to those documented in the literature for recessive loss-of-function alleles causing Crisponi or Bohring-Opitz like cold-induced sweating syndrome. Results Genetic testing in three patients identified two novel variants within the 3-box motif of the BACK domain: c.472 T > C:p.(Cys158Arg) and c.433A > T:p.(Asn145Tyr). Clinical imaging demonstrated hyperautofluorescent ring formation on both SW-AF and NIR-AF in three patients, with diffuse peripheral and peripapillary atrophy seen in all but one case. SD-OCT demonstrated a phenotypic spectrum, from parafoveal atrophy of the outer retina with foveal sparing to widespread retinal thinning and loss of photoreceptors. Incidence of cystoid macular edema was high with four of five patients affected. Protein modeling of dominant alleles versus recessive loss-of-function alleles showed dominant alleles localized to the BTB and BACK domains while recessive alleles were found in the Kelch domain. Conclusions We report the phenotype in five patients with KLHL7 mediated adRP, two novel coding variants, and imaging biomarkers using SW-AF and NIR-AF. These findings may influence future gene-based therapies for adRP and pave the way for mechanistic studies that elucidate the pathogenesis of KLHL7-mediated RP.

scholarly journals Germline variants and phenotypic spectrum in a Canadian cohort of individuals with diffuse gastric cancer

2019 ◽  
Vol 27 (2) ◽  
Author(s):  
M. Aronson ◽  
C. Swallow ◽  
A. Govindarajan ◽  
K. Semotiuk ◽  
Z. Cohen ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Detection Rate ◽  
Gene Panel ◽  
Diffuse Gastric Cancer ◽  
Cancer Syndrome ◽  
Detection Rates ◽  
Inherited Cancer ◽  
Panel Testing ◽  
Pathogenic Variants ◽  
Gene Panel Testing

Background CDH1 pathogenic variants (PV) cause the majority of inherited diffuse-gastric cancer (DGC), but have low detection rates and vary geographically. This study examines hereditary causes of DGC in patients from Ontario, Canada. Methods Eligible DGC cases at the Zane Cohen Centre (ZCC) underwent multi-gene panel or CDH1 single-site testing if they met 2015 International Gastric Cancer Linkage Consortium (IGCLC) criteria, isolated DGC <50 or family history suggestive of an inherited cancer syndrome. A secondary aim was to review all CDH1 families at the ZCC to assess cancer penetrance. Results 85 DGC patients underwent CDH1 (n=43) or multi-gene panel testing (n=42), and 15 (17.6%) PV or likely PV were identified.  CDH1 detection rate was 9.4% (n=8/85), and 11% (n=7/65) using IGCLC criteria.  No CDH1 PV identified in isolated DGC <40, but one PV identified in isolated DGC<50.  Multi-gene panel from 42 individuals identified 9 PV (21.4%) including CDH1, STK11, ATM, BRCA2, MLH1 and MSH2.  Review of 81 CDH1 carriers revealed that 10% had DGC (median age:48, range:38-59), 41% were unaffected (median age:53, range:26-89).  Three families had lobular-breast cancer (LBC) only.  Non-DGC/LBC malignancies included colorectal, gynecological, kidney/bladder, prostate, testicular and ductal breast. Conclusions Low detection rate of CDH1 in Ontario DGC patients.  No CDH1 PV found in isolated DGC <40, but identified in isolated DGC<50. Multi-gene panels are recommended for all DGC under age 50, and those meeting the IGCLC criteria, given overlapping phenotype with other hereditary conditions. HDGC phenotype is evolving with a spectrum of non-DGC/LBC cancers.

scholarly journals Stop-gain mutations in UBAP1 cause pure autosomal-dominant spastic paraplegia

Brain ◽  
2019 ◽  
Vol 142 (8) ◽  
pp. 2238-2252 ◽  
Author(s):  
Xiang Lin ◽  
Hui-Zhen Su ◽  
En-Lin Dong ◽  
Xiao-Hong Lin ◽  
Miao Zhao ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Cortical Neurons ◽  
Hereditary Spastic Paraplegia ◽  
Autosomal Dominant ◽  
Wild Type Mouse ◽  
Spastic Paraplegia ◽  
Endosomal Sorting ◽  
Hereditary Spastic Paraplegias ◽  
Cultured Cortical Neurons

Abstract Hereditary spastic paraplegias refer to a heterogeneous group of neurodegenerative disorders resulting from degeneration of the corticospinal tract. Clinical characterization of patients with hereditary spastic paraplegias represents progressive spasticity, exaggerated reflexes and muscular weakness. Here, to expand on the increasingly broad pools of previously unknown hereditary spastic paraplegia causative genes and subtypes, we performed whole exome sequencing for six affected and two unaffected individuals from two unrelated Chinese families with an autosomal dominant hereditary spastic paraplegia and lacking mutations in known hereditary spastic paraplegia implicated genes. The exome sequencing revealed two stop-gain mutations, c.247_248insGTGAATTC (p.I83Sfs*11) and c.526G>T (p.E176*), in the ubiquitin-associated protein 1 (UBAP1) gene, which co-segregated with the spastic paraplegia. We also identified two UBAP1 frameshift mutations, c.324_325delCA (p.H108Qfs*10) and c.425_426delAG (p.K143Sfs*15), in two unrelated families from an additional 38 Chinese pedigrees with autosomal dominant hereditary spastic paraplegias and lacking mutations in known causative genes. The primary disease presentation was a pure lower limb predominant spastic paraplegia. In vivo downregulation of Ubap1 in zebrafish causes abnormal organismal morphology, inhibited motor neuron outgrowth, decreased mobility, and shorter lifespan. UBAP1 is incorporated into endosomal sorting complexes required for transport complex I and binds ubiquitin to function in endosome sorting. Patient-derived truncated form(s) of UBAP1 cause aberrant endosome clustering, pronounced endosome enlargement, and cytoplasmic accumulation of ubiquitinated proteins in HeLa cells and wild-type mouse cortical neuron cultures. Biochemical and immunocytochemical experiments in cultured cortical neurons derived from transgenic Ubap1flox mice confirmed that disruption of UBAP1 leads to dysregulation of both early endosome processing and ubiquitinated protein sorting. Strikingly, deletion of Ubap1 promotes neurodegeneration, potentially mediated by apoptosis. Our study provides genetic and biochemical evidence that mutations in UBAP1 can cause pure autosomal dominant spastic paraplegia.

scholarly journals One in three highly selected Greek patients with breast cancer carries a loss-of-function variant in a cancer susceptibility gene

2019 ◽  
Vol 57 (1) ◽  
pp. 53-61 ◽  
Author(s):  
Florentia Fostira ◽  
Irene Kostantopoulou ◽  
Paraskevi Apostolou ◽  
Myrto S Papamentzelopoulou ◽  
Christos Papadimitriou ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Susceptibility ◽  
Susceptibility Gene ◽  
Gene Panel ◽  
Control Analysis ◽  
Loss Of Function ◽  
Panel Testing ◽  
Pathogenic Variants ◽  
Gene Panel Testing ◽  
Clinical Changes

BackgroundGene panel testing has become the norm for assessing breast cancer (BC) susceptibility, but actual cancer risks conferred by genes included in panels are not established. Contrarily, deciphering the missing hereditability on BC, through identification of novel candidates, remains a challenge. We aimed to investigate the mutation prevalence and spectra in a highly selected cohort of Greek patients with BC, questioning an extensive number of genes, implicated in cancer predisposition and DNA repair, while calculating gene-specific BC risks that can ultimately lead to important associations.MethodsTo further discern BC susceptibility, a comprehensive 94-cancer gene panel was implemented in a cohort of 1382 Greek patients with BC, highly selected for strong family history and/or very young age (<35 years) at diagnosis, followed by BC risk calculation, based on a case–control analysis.ResultsHerein, 31.5% of patients tested carried pathogenic variants (PVs) in 28 known, suspected or candidate BC predisposition genes. In total, 24.8% of the patients carried BRCA1/2 loss-of-function variants. An additional 6.7% carried PVs in additional genes, the vast majority of which can be offered meaningful clinical changes. Significant association to BC predisposition was observed for ATM, PALB2, TP53, RAD51C and CHEK2 PVs. Primarily, compared with controls, RAD51C PVs and CHEK2 damaging missense variants were associated with high (ORs 6.19 (Exome Aggregation Consortium (ExAC)) and 12.6 (Fabulous Ladies Over Seventy (FLOSSIES)), p<0.01) and moderate BC risk (ORs 3.79 (ExAC) and 5.9 (FLOSSIES), p<0.01), respectively.ConclusionStudying a large and unique cohort of highly selected patients with BC, deriving from a population with founder effects, provides important insight on distinct associations, pivotal for patient management.

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