Search

BACKGROUND: It is increasingly clear that genetic and non-genetic factors account for the association of family history with disease risk in offspring. We sought to distinguish the genetic and non-genetic contributions of family history of stroke and heart disease on incident events by examining adopted and non-adopted individuals. METHODS: We examined associations between family history of stroke and heart disease with incident stroke and myocardial infarction (MI) in 495,640 participants of the UK Biobank (mean age 56.5 years, 55% female) stratified by early childhood adoption status into adoptees (n=5,747) and non-adoptees (n=489,893). We estimated hazard ratios (HRs) per affected nuclear family member, and for polygenic risk scores (PRS) for stroke and MI in Cox models adjusted for baseline age and sex. RESULTS: 12,518 strokes and 23,923 MIs occurred over a 13-year follow-up. In non-adoptees, family history of stroke and heart disease were associated with increased stroke and MI risk, with the strongest association of family history of stroke for incident stroke (HR 1.16 [1.12, 1.19]) and family history of heart disease for incident MI (HR 1.48 [1.45, 1.50]). In adoptees, family history of stroke associated with incident stroke (HR 1.41 [1.06, 1.86]), but family history of heart disease did not associate with incident MI (p>0.5). PRS showed strong disease-specific associations in adoptees and non-adoptees. In non-adoptees, the stroke PRS mediated 6% risk between family history of stroke and incident stroke, and the MI PRS mediated 13% risk between family history of heart disease and MI. CONCLUSIONS: Family history of stroke and heart disease increase risk for their respective conditions. Family history of stroke contains a substantial proportion of potentially modifiable non-genetic risk, indicating a need for further research to elucidate these elements for novel prevention strategies, whereas family history of heart disease represents predominantly genetic risk.

International audience; Hereditary spastic paraplegia type 56 (SPG56-HSP) is a rare autosomal recessive disorder caused by loss of function mutations in CYP2U1, leading to an early-onset limbs spasticity, often complicated by additional neurological or extra-neurological manifestations. Given its low prevalence, the molecular bases underlying SPG56-HSP are still poorly understood, and effective treatment options are still lacking. Recently, through the generation and characterization of the SPG56-HSP mouse model, we were able to take few important steps forward in expanding our knowledge of the molecular background underlying this complex disease. Leveraging the Cyp2u1-/- mouse model we were able to identify several new diagnostics biomarkers (vitamin B2, coenzyme Q, neopterin, and interferon-alpha), as well as to highlight the key role played by the folate pathway in SPG56-HSP pathogenesis, providing a potential treatment option. In this review, we discuss the major role played by the Cyp2u1-/- model in dissecting clinical and biological aspects of the disease, opening the way to a series of new research paths ranging from clinical trials, biomarker testing, and to the expansion of the underlying genetic and molecular, emphasizing how basic mouse model characterization could contribute to advance research in the context of rare disorders.

Supplemental material, sj-docx-1-wso-10.1177_17474930231155816 for Pleiotropy analysis between lobar intracerebral hemorrhage and CSF β-amyloid highlights new and established associations by Sandro Marini, Jaeyoon Chung, Xudong Han, Xinyu Sun, Livia Parodi, Lindsay A Farrer, Jonathan Rosand, Jose Rafael Romero and Christopher D Anderson in International Journal of Stroke

Supplemental material, sj-docx-1-wso-10.1177_17474930231155816 for Pleiotropy analysis between lobar intracerebral hemorrhage and CSF β-amyloid highlights new and established associations by Sandro Marini, Jaeyoon Chung, Xudong Han, Xinyu Sun, Livia Parodi, Lindsay A Farrer, Jonathan Rosand, Jose Rafael Romero and Christopher D Anderson in International Journal of Stroke

Background Factors such as age, pre-injury health, and injury severity, account for less than 35% of outcome variability in traumatic brain injury (TBI). While some residual outcome variability may be attributable to genetic factors, published candidate gene association studies have often been underpowered and subject to publication bias. Methods We performed the first genome- and transcriptome-wide association studies (GWAS, TWAS) of genetic effects on outcome in TBI. The study population consisted of 5268 patients from prospective European and US studies, who attended hospital within 24 h of TBI, and satisfied local protocols for computed tomography. Findings The estimated heritability of TBI outcome was 0·26. GWAS revealed no genetic variants with genome-wide significance (p < 5 × 10−8), but identified 83 variants in 13 independent loci which met a lower pre-specified sub-genomic statistical threshold (p < 10−5). Similarly, none of the genes tested in TWAS met tissue-wide significance. An exploratory analysis of 75 published candidate variants associated with 28 genes revealed one replicable variant (rs1800450 in the MBL2 gene) which retained significance after correction for multiple comparison (p = 5·24 × 10−4). Interpretation While multiple novel loci reached less stringent thresholds, none achieved genome-wide significance. The overall heritability estimate, however, is consistent with the hypothesis that common genetic variation substantially contributes to inter-individual variability in TBI outcome. The meta-analytic approach to the GWAS and the availability of summary data allows for a continuous extension with additional cohorts as data becomes available.

Supplemental material, sj-docx-1-wso-10.1177_17474930221095696 for Shared genetic background between SARS-CoV-2 infection and large artery stroke by Livia Parodi, Evangelos Pavlos Myserlis, Jaeyoon Chung, Marios K Georgakis, Ernst Mayerhofer, Jonathan Henry, Bailey E Montgomery, Mandy Moy, Huichun Xu, Rainer Malik, Carl D Langefeld, Martin Dichgans, Daniel Woo, Jonathan Rosand and Christopher D Anderson in International Journal of Stroke

Background and aims: Increased risk of stroke, particularly large artery stroke (LAS), has been observed in patients with COVID-19. The biological processes underlying the observed higher risk are still unknown. We explored the association between stroke subtypes and COVID-19 susceptibility to understand whether biological mechanisms specific to SARS-CoV-2 uptake/infection could be leading to excess stroke risk in this population. Patients and methods: We constructed a polygenic risk score (PRS) of COVID-19 susceptibility and tested its association with stroke subtypes using individual- and summary-level genetic data (SiGN, MEGASTROKE). We generated co-expression networks of genes involved in SARS-CoV-2 uptake/infection ( ACE2, TMPRSS2, BEST3, ISLR2 and ADAM17) based on existing tissue expression libraries. Gene-based association testing was performed using S-PrediXcan and VEGAS2. Permutation independence tests were performed to assess SARS-CoV-2-related gene enrichment in stroke and its subtypes. Results: Our PRS demonstrated an association between COVID-19 susceptibility and LAS in SiGN (OR = 1.05 per SD increase, 95% CI: (1.00, 1.10), p = 0.04) and MEGASTROKE (β = 0.510, 95% CI: (0.242, 0.779), FDR-p = 0.0019). The SARS-CoV-2 risk-related ISLR2 co-expression gene network was significantly associated with genetic risk of LAS in aorta, tibial arteries, and multiple brain regions (P Conclusion: Presence of genetic correlation and significant pathway enrichment suggest that increases in LAS risk reported in COVID-19 patients may be intrinsic to the viral infection, rather than a more generalized response to severe illness.

Ischemic stroke etiology remains undetermined in 30% of cases. We explored the genetic architecture of stroke classified as undetermined to test if mechanisms and risk factors underlying large-artery atherosclerotic (LAAS), cardioembolic (CES), and small-vessel stroke (SVS) contribute to its pathogenesis.We analyzed genome-wide data from 16,851 ischemic stroke cases and 32,473 controls. Using polygenic risk scores for LAAS, CES, and SVS, we assessed the genetic overlap with stroke of undetermined source and used pairwise genomewide association study (GWAS-PW) to search for shared loci. We then applied Mendelian randomization (MR) to identify potentially causal risk factors of stroke of undetermined source.Genetic risk for LAS, CES, and SVS was associated with stroke of undetermined source pointing to overlap in their genetic architecture. Pairwise analyses revealed 19 shared loci with LAAS, 2 with CES, and 5 with SVS that have been implicated in atherosclerosis-related phenotypes. Genetic liability to both carotid atherosclerosis and atrial fibrillation was associated with stroke of undetermined source, but the association with atrial fibrillation was attenuated after excluding cases with incomplete diagnostic workup. MR analyses showed effects of genetically determinants of blood pressure, diabetes, waist-to-hip ratio, inflammatory pathways (IL-6 signaling, MCP-1/CCL2 levels), and factor XI levels on stroke of undetermined source.Stroke of undetermined source shares genetic and vascular risk factors with other stroke subtypes, especially LAAS, thus highlighting the diagnostic limitations of current subtyping approaches. The potentially causal associations with carotid atherosclerosis and atherosclerotic risk factors might have implications for prevention strategies targeting these mechanisms. ANN NEUROL 2022;91:640-651.

Supplemental material, sj-docx-1-wso-10.1177_17474930221095696 for Shared genetic background between SARS-CoV-2 infection and large artery stroke by Livia Parodi, Evangelos Pavlos Myserlis, Jaeyoon Chung, Marios K Georgakis, Ernst Mayerhofer, Jonathan Henry, Bailey E Montgomery, Mandy Moy, Huichun Xu, Rainer Malik, Carl D Langefeld, Martin Dichgans, Daniel Woo, Jonathan Rosand and Christopher D Anderson in International Journal of Stroke

OBJECTIVE: Ischemic stroke etiology remains undetermined in 30% of cases. We explored the genetic architecture of stroke classified as undetermined to test if mechanisms and risk factors underlying large-artery atherosclerotic (LAAS), cardioembolic (CES), and small-vessel stroke (SVS) contribute to its pathogenesis. METHODS: We analyzed genome-wide data from 16,851 ischemic stroke cases and 32,473 controls. Using polygenic risk scores for LAAS, CES, and SVS, we assessed the genetic overlap with stroke of undetermined source and used pairwise genomewide association study (GWAS-PW) to search for shared loci. We then applied Mendelian randomization (MR) to identify potentially causal risk factors of stroke of undetermined source. RESULTS: Genetic risk for LAS, CES, and SVS was associated with stroke of undetermined source pointing to overlap in their genetic architecture. Pairwise analyses revealed 19 shared loci with LAAS, 2 with CES, and 5 with SVS that have been implicated in atherosclerosis-related phenotypes. Genetic liability to both carotid atherosclerosis and atrial fibrillation was associated with stroke of undetermined source, but the association with atrial fibrillation was attenuated after excluding cases with incomplete diagnostic workup. MR analyses showed effects of genetically determinants of blood pressure, diabetes, waist-to-hip ratio, inflammatory pathways (IL-6 signaling, MCP-1/CCL2 levels), and factor XI levels on stroke of undetermined source. INTERPRETATION: Stroke of undetermined source shares genetic and vascular risk factors with other stroke subtypes, especially LAAS, thus highlighting the diagnostic limitations of current subtyping approaches. The potentially causal associations with carotid atherosclerosis and atherosclerotic risk factors might have implications for prevention strategies targeting these mechanisms. ANN NEUROL 2022.

Hereditary Spastic Paraplegias (HSPs) are a group of rare, inherited, neurodegenerative disorders that arise following the progressive degeneration of the corticospinal tracts, leading to lower limbs spasticity, the disorder hallmark. HSPs are characterized by an extreme heterogeneity that encompasses both genetic and clinical features, extending to additional disorder’s features, such as age of onset and severity. This phenotypic variability is typically observed among HSP patients carrying pathogenic mutations in SPAST, the most frequently mutated HSP causative gene. After assembling a cohort of 842 SPAST-HSP patients, a combination of different Next Generation Sequencing approaches was used to dig deeper into the causes of the observed heterogeneity, especially focusing on the identification of age of onset genetic modifiers. Sequencing data resulting from Whole Genome Genotyping were used to perform both association and linkage analysis that, combined with RNA sequencing expression data, allowed to identify different candidate variants/genes, potentially acting as SPAST-HSP age of onset modifiers.; Les Paraplégies Spastiques Héréditaires (PSHs) sont un groupe de maladies neurodégénératives rares qui surviennent suite à la dégénérescence progressive des voies corticospinales, entraînant une spasticité des membres inférieurs, signe distinctif de la pathologie. Elles se caractérisent par une extrême hétérogénéité qui concerne à la fois les facteurs génétiques et cliniques, ainsi que d’autres aspects de la maladie, tels que l’âge d’apparition et la sévérité des signes. Cette variabilité est typiquement observée chez les patients porteurs de mutations pathogènes dans SPAST, le gène le plus fréquemment muté dans les PSHs. Après avoir réuni une cohorte de 842 patients mutés dans SPAST, nous avons utilisé une combinaison de différentes approches de Séquençage de Nouvelle Génération (NGS) afin de mieux comprendre les causes de l’hétérogénéité observée chez les patients, afin d’identifier des facteurs génétiques responsables de variations de l’âge au début de la maladie. Les données résultantes du génotypage de l’ensemble du génome ont ainsi été utilisées pour effectuer des analyses d’association et de liaison qui, combinées aux données de séquençage de l’ARN, ont permis d’identifier différents variantes/gènes candidats, potentiellement impliqués comme facteurs modificateurs de l’âge de début des SPAST-PSHs.

Hereditary Spastic Paraplegias (HSPs) are a group of rare, inherited, neurodegenerative disorders that arise following the progressive degeneration of the corticospinal tracts, leading to lower limbs spasticity, the disorder hallmark. HSPs are characterized by an extreme heterogeneity that encompasses both genetic and clinical features, extending to additional disorder’s features, such as age of onset and severity. This phenotypic variability is typically observed among HSP patients carrying pathogenic mutations in SPAST, the most frequently mutated HSP causative gene. After assembling a cohort of 842 SPAST-HSP patients, a combination of different Next Generation Sequencing approaches was used to dig deeper into the causes of the observed heterogeneity, especially focusing on the identification of age of onset genetic modifiers. Sequencing data resulting from Whole Genome Genotyping were used to perform both association and linkage analysis that, combined with RNA sequencing expression data, allowed to identify different candidate variants/genes, potentially acting as SPAST-HSP age of onset modifiers., Les Paraplégies Spastiques Héréditaires (PSHs) sont un groupe de maladies neurodégénératives rares qui surviennent suite à la dégénérescence progressive des voies corticospinales, entraînant une spasticité des membres inférieurs, signe distinctif de la pathologie. Elles se caractérisent par une extrême hétérogénéité qui concerne à la fois les facteurs génétiques et cliniques, ainsi que d’autres aspects de la maladie, tels que l’âge d’apparition et la sévérité des signes. Cette variabilité est typiquement observée chez les patients porteurs de mutations pathogènes dans SPAST, le gène le plus fréquemment muté dans les PSHs. Après avoir réuni une cohorte de 842 patients mutés dans SPAST, nous avons utilisé une combinaison de différentes approches de Séquençage de Nouvelle Génération (NGS) afin de mieux comprendre les causes de l’hétérogénéité observée chez les patients, afin d’identifier des facteurs génétiques responsables de variations de l’âge au début de la maladie. Les données résultantes du génotypage de l’ensemble du génome ont ainsi été utilisées pour effectuer des analyses d’association et de liaison qui, combinées aux données de séquençage de l’ARN, ont permis d’identifier différents variantes/gènes candidats, potentiellement impliqués comme facteurs modificateurs de l’âge de début des SPAST-PSHs.

Hereditary spastic paraplegia refers to rare genetic neurodevelopmental and/or neurodegenerative disorders in which spasticity due to length-dependent damage to the upper motor neuron is a core sign. Their high clinical and genetic heterogeneity makes their diagnosis challenging. Multigene panels allow a high-throughput targeted analysis of the increasing number of genes involved using next-generation sequencing. We report here the clinical and genetic results of 1550 index cases tested for variants in a panel of hereditary spastic paraplegia related genes analysed in routine diagnosis. A causative variant was found in 475 patients (30.7%) in 35/65 screened genes. SPAST and SPG7 were the most frequently mutated genes, representing 142 (9.2%) and 75 (4.8%) index cases of the whole series, respectively. KIF1A, ATL1, SPG11, KIF5A and REEP1 represented more than 1% (>17 cases) each. There were 661 causative variants (382 different ones) and 30 of them were structural variants. This large cohort allowed us to obtain an overview of the clinical and genetic spectrum of hereditary spastic paraplegia in clinical practice. Because of the wide phenotypic variability, there was no very specific sign that could predict the causative gene, but there were some constellations of symptoms that were found often related to specific subtypes. Finally, we confirmed the diagnostic effectiveness of a targeted sequencing panel as a first-line genetic test in hereditary spastic paraplegia. This is a pertinent strategy because of the relative frequency of several known genes (i.e. SPAST, KIF1A) and it allows identification of variants in the rarest involved genes and detection of structural rearrangements via coverage analysis, which is less efficient in exome datasets. It is crucial because these structural variants represent a significant proportion of the pathogenic hereditary spastic paraplegia variants (∼6% of patients), notably for SPAST and REEP1. In a subset of 42 index cases negative for the targeted multigene panel, subsequent whole-exome sequencing allowed a theoretical diagnosis yield of ∼50% to be reached. We then propose a two-step strategy combining the use of a panel of genes followed by whole-exome sequencing in negative cases.