Obesity-linked suppression of membrane-bound O-acyltransferase 7 (MBOAT7) drives non-alcoholic fatty liver disease.

Recent studies have identified a genetic variant rs641738 near two genes encoding membrane bound O-acyltransferase domain-containing 7 (MBOAT7) and transmembrane channel-like 4 (TMC4) that associate with increased risk of non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH), alcohol-related cirrhosis, and liver fibrosis in those infected with viral hepatitis (Buch et al., 2015; Mancina et al., 2016; Luukkonen et al., 2016; Thabet et al., 2016; Viitasalo et al., 2016; Krawczyk et al., 2017; Thabet et al., 2017). Based on hepatic expression quantitative trait loci analysis, it has been suggested that MBOAT7 loss of function promotes liver disease progression (Buch et al., 2015; Mancina et al., 2016; Luukkonen et al., 2016; Thabet et al., 2016; Viitasalo et al., 2016; Krawczyk et al., 2017; Thabet et al., 2017), but this has never been formally tested. Here we show that Mboat7 loss, but not Tmc4, in mice is sufficient to promote the progression of NAFLD in the setting of high fat diet. Mboat7 loss of function is associated with accumulation of its substrate lysophosphatidylinositol (LPI) lipids, and direct administration of LPI promotes hepatic inflammatory and fibrotic transcriptional changes in an Mboat7-dependent manner. These studies reveal a novel role for MBOAT7-driven acylation of LPI lipids in suppressing the progression of NAFLD

A structural variation reference for medical and population genetics

Structural variants (SVs) rearrange large segments of DNA1 and can have profound consequences in evolution and human disease2,3. As national biobanks, disease-association studies, and clinical genetic testing have grown increasingly reliant on genome sequencing, population references such as the Genome Aggregation Database (gnomAD)4 have become integral in the interpretation of single-nucleotide variants (SNVs)5. However, there are no reference maps of SVs from high-coverage genome sequencing comparable to those for SNVs. Here we present a reference of sequence-resolved SVs constructed from 14,891 genomes across diverse global populations (54% non-European) in gnomAD. We discovered a rich and complex landscape of 433,371 SVs, from which we estimate that SVs are responsible for 25–29% of all rare protein-truncating events per genome. We found strong correlations between natural selection against damaging SNVs and rare SVs that disrupt or duplicate protein-coding sequence, which suggests that genes that are highly intolerant to loss-of-function are also sensitive to increased dosage6. We also uncovered modest selection against noncoding SVs in cis-regulatory elements, although selection against protein-truncating SVs was stronger than all noncoding effects. Finally, we identified very large (over one megabase), rare SVs in 3.9% of samples, and estimate that 0.13% of individuals may carry an SV that meets the existing criteria for clinically important incidental findings7. This SV resource is freely distributed via the gnomAD browser8 and will have broad utility in population genetics, disease-association studies, and diagnostic screening.</p

Generating Synthetic Computed Tomography for Radiotherapy: SynthRAD2023 Challenge Report

Radiation therapy plays a crucial role in cancer treatment, necessitating precise delivery of radiation to tumors while sparing healthy tissues over multiple days. Computed tomography (CT) is integral for treatment planning, offering electron density data crucial for accurate dose calculations. However, accurately representing patient anatomy is challenging, especially in adaptive radiotherapy, where CT is not acquired daily. Magnetic resonance imaging (MRI) provides superior soft-tissue contrast. Still, it lacks electron density information while cone beam CT (CBCT) lacks direct electron density calibration and is mainly used for patient positioning. Adopting MRI-only or CBCT-based adaptive radiotherapy eliminates the need for CT planning but presents challenges. Synthetic CT (sCT) generation techniques aim to address these challenges by using image synthesis to bridge the gap between MRI, CBCT, and CT. The SynthRAD2023 challenge was organized to compare synthetic CT generation methods using multi-center ground truth data from 1080 patients, divided into two tasks: 1) MRI-to-CT and 2) CBCT-to-CT. The evaluation included image similarity and dose-based metrics from proton and photon plans. The challenge attracted significant participation, with 617 registrations and 22/17 valid submissions for tasks 1/2. Top-performing teams achieved high structural similarity indices (>0.87/0.90) and gamma pass rates for photon (>98.1%/99.0%) and proton (>97.3%/97.0%) plans. However, no significant correlation was found between image similarity metrics and dose accuracy, emphasizing the need for dose evaluation when assessing the clinical applicability of sCT. SynthRAD2023 facilitated the investigation and benchmarking of sCT generation techniques, providing insights for developing MRI-only and CBCT-based adaptive radiotherapy.Comment: Preprint submitted to Medical Image Analysi

Generating synthetic computed tomography for radiotherapy: SynthRAD2023 challenge report

Radiation therapy plays a crucial role in cancer treatment, necessitating precise delivery of radiation to tumors while sparing healthy tissues over multiple days. Computed tomography (CT) is integral for treatment planning, offering electron density data crucial for accurate dose calculations. However, accurately representing patient anatomy is challenging, especially in adaptive radiotherapy, where CT is not acquired daily. Magnetic resonance imaging (MRI) provides superior soft-tissue contrast. Still, it lacks electron density information, while cone beam CT (CBCT) lacks direct electron density calibration and is mainly used for patient positioning. Adopting MRI-only or CBCT-based adaptive radiotherapy eliminates the need for CT planning but presents challenges. Synthetic CT (sCT) generation techniques aim to address these challenges by using image synthesis to bridge the gap between MRI, CBCT, and CT. The SynthRAD2023 challenge was organized to compare synthetic CT generation methods using multi-center ground truth data from 1080 patients, divided into two tasks: (1) MRI-to-CT and (2) CBCT-to-CT. The evaluation included image similarity and dose-based metrics from proton and photon plans. The challenge attracted significant participation, with 617 registrations and 22/17 valid submissions for tasks 1/2. Top-performing teams achieved high structural similarity indices (≥0.87/0.90) and gamma pass rates for photon (≥98.1%/99.0%) and proton (≥97.3%/97.0%) plans. However, no significant correlation was found between image similarity metrics and dose accuracy, emphasizing the need for dose evaluation when assessing the clinical applicability of sCT. SynthRAD2023 facilitated the investigation and benchmarking of sCT generation techniques, providing insights for developing MRI-only and CBCT-based adaptive radiotherapy. It showcased the growing capacity of deep learning to produce high-quality sCT, reducing reliance on conventional CT for treatment planning

Lo que los padres varones de un hijo con síndrome de Down piensan sobre el actual test prenatal no invasivo para el síndrome de Down

El test prenatal no-invasivo (TPNI) permite realizar un diagnóstico temprano y preciso de síndrome de Down que ha terminado por incrementar el número de abortos. Este estudio cualitativo consistió en la realización de entrevistas en profundidad a padres (varones) de niños con síndrome de Down y sus opiniones sobre la disponibilidad del TPNI. El análisis temático en red reveló que aunque los padres estimaban la existencia de un diagnóstico temprano con el TPNI, veían que el test se convertía en una vía predeterminada hacia el aborto. Los padres opinaron que la expectativa (dar por supuesto) de terminar el embarazo refleja actitudes negativas de la sociedad hacia quienes tienen síndrome de Down u otra discapacidad, y temen que el TPNI se convierta en una forma de eugenesia. Los padres, de manera retrospectiva, contrastaron estas actitudes con la realidad actual de la crianza de sus hijos con síndrome de Down, a la que describen como portadora de felicidad a sus vidas. Los resultados sugieren que, aunque los padres valoran el TPNI como instrumento informativo que permite que los padres decidan de forma autónoma sobre su embarazo, creen que debería estar acompañado de una información equilibrada sobre la realidad de cómo es la crianza de un hijo con síndrome de Down.Non-invasive prenatal testing (NIPT) allows early, accurate diagnosis of Down syndrome that has resulted in increased terminations. This qualitative study involved in-depth interviews of fathers of children with Down syndrome about their views on the availability of NIPT. Thematic network analysis revealed that although fathers appreciated an early diagnosis with NIPT, they saw the test as being a predetermined pathway to termination. Fathers felt that expectation to terminate reflects negative societal attitudes toward those with Down syndrome and disability, fearing that NIPT may become a form of eugenics. Fathers retrospectively contrasted these attitudes with the actual reality of raising their children with Down syndrome, which they described as bringing joy to their lives. Findings suggest that although fathers valued NIPT as an information-giving tool that allowed autonomous parental choices about the pregnancy, they believe that it should be accompanied by balanced information about the reality of raising a child with Down syndrome

'We would have missed out so much had we terminated' : what fathers of a child with Down syndrome think about current non-invasive prenatal testing for Down syndrome

Non-invasive prenatal testing (NIPT) allows early, accurate diagnosis of Down syndrome that has resulted in increased terminations. This qualitative study involved in-depth interviews of fathers of children with Down syndrome about their views on the availability of NIPT. Thematic network analysis revealed that although fathers appreciated an early diagnosis with NIPT, they saw the test as being a predetermined pathway to termination. Fathers felt that expectation to terminate reflects negative societal attitudes towards those with Down syndrome and disability, fearing that NIPT may become a form of eugenics. Fathers retrospectively contrasted these attitudes with the actual reality of raising their children with Down syndrome, which they described as bringing joy to their lives. Findings suggest that although fathers valued NIPT as an information-giving tool that allowed autonomous parental choices about the pregnancy, they believe that it should be accompanied by balanced information about the reality of raising a child with Down syndrome

Mothers of a child with Down syndrome : a qualitative analysis of the perspectives on non-invasive prenatal testing

Objective: The introduction of non-invasive prenatal testing (NIPT) for Down syndrome (DS) has sparked social and ethical debates. To date, in-depth exploration of the voices of Australian mothers of a child with DS about NIPT has been lacking. The purpose of this study was to investigate the perspectives of Australian mothers of a child with DS towards the increasing availability of NIPT. Design and Setting: Fifteen mothers of children with DS aged 8 months–39 years participated in-depth interviews, conducted online via the software Zoom™. An inductive thematic analysis of interview data explored mothers’ perceptions of NIPT. Findings: Mothers perspectives were nuanced and personal to each woman's circumstance. All mothers highlighted the inevitable association between testing and termination, the importance of autonomy and respecting [m]others’ choices to test and to terminate, and that appropriate supports must be provided to ensure informed decision-making. These perspectives existed within an overarching theme of NIPT reflecting and reinforcing societal attitudes towards disability. Conclusion: Mothers of a child with DS viewed informed decision-making as crucial both prior to undertaking NIPT and following a positive test result. This study adds a unique Australian perspective to the necessary ongoing social and ethical debate

(We would have missed out so much had we terminated : what fathers of a child with Down syndrome think about current non-invasive prenatal testing for Down syndrome)

Non-invasive prenatal testing (NIPT) allows early, accurate diagnosis of Down syndrome that has resulted in increased terminations. This qualitative study involved in-depth interviews of fathers of children with Down syndrome about their views on the availability of NIPT. Thematic network analysis revealed that although fathers appreciated an early diagnosis with NIPT, they saw the test as being a predetermined pathway to termination. Fathers felt that expectation to terminate reflects negative societal attitudes toward those with Down syndrome and disability, fearing that NIPT may become a form of eugenics. Fathers retrospectively contrasted these attitudes with the actual reality of raising their children with Down syndrome, which they described as bringing joy to their lives. Findings suggest that although fathers valued NIPT as an information-giving tool that allowed autonomous parental choices about the pregnancy, they believe that it should be accompanied by balanced information about the reality of raising a child with Down syndrome