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Background Transient elastography (TE) is a rapid noninvasive ultrasound-based technology that measures liver stiffness as a surrogate for liver fibrosis and controlled attenuation parameter (CAP) as a measure of liver steatosis. However, normal ranges in children are not well defined in all populations. The aim of this study was to determine transient elastography values in healthy South African children. Methods From April 2019 to December 2021, children were recruited from the HIV negative control group of a cohort study. Only children neither overweight nor obese, without evidence of liver disease, no medical condition or medication associated with hepatic steatosis or fibrosis and normal metabolic profile were included in this cross-sectional analysis. Clinical data, anthropometry and blood samples were collected on the same day as transient elastography with controlled attenuation parameter was performed. Results 104 children (median age 12.8 years [IQR 11.4–14.8, range 7.9–17.7 years]; 59 [57%] boys) were included. Liver stiffness was positively correlated with age (Pearson’s r = 0.39, p < 0.001). Median liver stiffness in boys (5.2 kPa [5th to 95th percentiles 3.6 to 6.8 kPa]) was greater than in girls (4.6 kPa [5th to 95th percentiles 3.6 to 6.1 kPa; p = 0.004]), but there was no difference by ethnicity. Median CAP was 179dB/m (5th to 95th percentiles 158 to 233dB/m). There was a positive correlation between CAP and body mass index (BMI) z-score, but no difference by age, sex, ethnicity or pubertal status. Conclusion Liver stiffness values increase with age and are higher in healthy South African boys than girls, whereas CAP values vary with BMI, but not with age or sex.

MPV17-related mitochondrial DNA depletion syndrome is a rare, lethal, autosomal recessive primary mitochondrial disorder characterised by infantile onset liver disease and neurological features, including hypotonia, developmental delay, failure to thrive and neuropathy. The aim of this study was to describe the presentation and clinical course of infants diagnosed with MPV17 neurohepatopathy, comparing those who were HIV-exposed on antiretroviral therapy (ART), including zidovudine and nevirapine to prevent perinatal HIV transmission, to infants who were not HIV exposed, using data from a multicentre MPV17 natural history study in South Africa. Between 2013 and 2024, 25 infants were diagnosed with MPV17 neurohepatopathy, 8 (32%) of whom were HIV-exposed and received ART at birth (7 received zidovudine), none were HIV-infected. Median birth weight was lower at 2.45 kg (IQR 2.28-2.71) in infants who were HIV-exposed compared to 2.86 kg (IQR 2.54-3.13) in HIV-unexposed infants (p = 0.02). Symptom onset occurred much earlier at a median of 3 days of age (IQR 0-10 days) in HIV-exposed infants compared to 60 days (IQR 14-90) in HIV-unexposed (p = 0.006). Infants exposed to HIV were more likely to develop liver failure (p = 0.02). Perinatal therapy with the nucleoside reverse transcriptase inhibitor zidovudine, a known mitochondrial toxin, was associated with accelerated clinical presentation and clinical course of MPV17 neurohepatopathy. Our findings suggest that less toxic antiretroviral therapy should be considered for perinatal HIV prophylaxis in HIV-exposed infants, particularly in our setting where there is a high carrier frequency of a single pathogenic MPV17 variant.

Tobacco and alcohol use are leading causes of mortality that influence risk for many complex diseases and disorders 1 . They are heritable 2 , 3 and etiologically related 4 , 5 behaviors that have been resistant to gene discovery efforts 6 – 11 . In sample sizes up to 1.2 million individuals, we discovered 566 genetic variants in 406 loci associated with multiple stages of tobacco use (initiation, cessation, and heaviness) as well as alcohol use, with 150 loci evidencing pleiotropic association. Smoking phenotypes were positively genetically correlated with many health conditions, whereas alcohol use was negatively correlated with these conditions, such that increased genetic risk for alcohol use is associated with lower disease risk. We report evidence for the involvement of many systems in tobacco and alcohol use, including genes involved in nicotinic, dopaminergic, and glutamatergic neurotransmission. The results provide a solid starting point to evaluate the effects of these loci in model organisms and more precise substance use measures. Association studies of up to 1.2 million individuals identify 566 genetic variants in 406 loci associated with tobacco use and addiction (initiation, cessation, and heaviness) as well as alcohol use, with 150 loci showing pleiotropic association.

Identifying genetic determinants of reproductive success may highlight mechanisms underlying fertility and identify alleles under present-day selection. Using data in 785,604 individuals of European ancestry, we identified 43 genomic loci associated with either number of children ever born (NEB) or childlessness. These loci span diverse aspects of reproductive biology, including puberty timing, age at first birth, sex hormone regulation, endometriosis and age at menopause. Missense variants in ARHGAP27 were associated with higher NEB but shorter reproductive lifespan, suggesting a trade-off at this locus between reproductive ageing and intensity. Other genes implicated by coding variants include PIK3IP1 , ZFP82 and LRP4 , and our results suggest a new role for the melanocortin 1 receptor ( MC1R ) in reproductive biology. As NEB is one component of evolutionary fitness, our identified associations indicate loci under present-day natural selection. Integration with data from historical selection scans highlighted an allele in the FADS1/2 gene locus that has been under selection for thousands of years and remains so today. Collectively, our findings demonstrate that a broad range of biological mechanisms contribute to reproductive success. Mathieson et al. carried out a genome-wide association study of reproductive success (number of children born) in humans, revealing the importance of diverse neuro-endocrine and behavioural factors.

Genome-wide association meta-analysis (GWAMA) is an effective approach to enlarge sample sizes and empower the discovery of novel associations between genotype and phenotype. Independent replication has been used as a gold-standard for validating genetic associations. However, as current GWAMA often seeks to aggregate all available datasets, it becomes impossible to find a large enough independent dataset to replicate new discoveries. Here we introduce a method, MAMBA (Meta-Analysis Model-based Assessment of replicability), for assessing the “posterior-probability-of-replicability” for identified associations by leveraging the strength and consistency of association signals between contributing studies. We demonstrate using simulations that MAMBA is more powerful and robust than existing methods, and produces more accurate genetic effects estimates. We apply MAMBA to a large-scale meta-analysis of addiction phenotypes with 1.2 million individuals. In addition to accurately identifying replicable common variant associations, MAMBA also pinpoints novel replicable rare variant associations from imputation-based GWAMA and hence greatly expands the set of analyzable variants. In genome-wide association meta-analysis, it is often difficult to find an independent dataset of sufficient size to replicate associations. Here, the authors have developed MAMBA to calculate the probability of replicability based on consistency between datasets within the meta-analysis.

Vaccination of human immunodeficiency virus (HIV)-infected infants with bacille Calmette-Guérin (BCG) is contraindicated. HIV-exposed newborns need a new tuberculosis vaccination strategy that protects against tuberculosis early in life and avoids the potential risk of BCG disease until after HIV infection has been excluded. This double-blind, randomized, controlled trial compared newborn MVA85A prime vaccination (1 × 108 PFU) vs Candin® control, followed by selective, deferred BCG vaccination at age 8 weeks for HIV-uninfected infants and 12 months follow-up for safety and immunogenicity. A total of 248 HIV-exposed infants were enrolled. More frequent mild-moderate reactogenicity events were seen after newborn MVA85A vaccination. However, no significant difference was observed in the rate of severe or serious adverse events, HIV acquisition (n = 1 per arm), or incident tuberculosis disease (n = 5 MVA85A; n = 3 control) compared to the control arm. MVA85A vaccination induced modest but significantly higher Ag85A-specific interferon gamma (IFNγ)+ CD4+ T cells compared to control at weeks 4 and 8 (P < .0001). BCG did not further boost this response in MVA85A vaccinees. The BCG-induced Ag85A-specific IFNγ+ CD4+ T-cell response at weeks 16 and 52 was of similar magnitude in the control arm compared to the MVA85A arm at all time points. Proliferative capacity, functional profiles, and memory phenotype of BCG-specific CD4 responses were similar across study arms. MVA85A prime vaccination of HIV-exposed newborns was safe and induced an early modest antigen-specific immune response that did not interfere with, or enhance, immunogenicity of subsequent BCG vaccination. New protein-subunit and viral-vectored tuberculosis vaccine candidates should be tested in HIV-exposed newborns. NCT01650389.

ObjectiveNeonatal infection with wildtype SARS-CoV-2 is rare and good outcomes predominate. We investigated neonatal outcomes using national population-level data to describe the impact of different SARS-CoV-2 variants.DesignProspective population-based cohort study.SettingNeonatal, paediatric and paediatric intensive care inpatient care settings in the UK.PatientsNeonates (first 28 days after birth) with confirmed SARS-CoV-2 infection who received inpatient care, March 2020 to April 2022. Neonates were identified through active national surveillance with linkage to national SARS-CoV-2 testing data, routinely recorded neonatal data, paediatric intensive care data and obstetric and perinatal mortality surveillance data.OutcomesPresenting signs, clinical course, severe disease requiring respiratory support are presented by the dominant SARS-CoV-2 variant in circulation at the time.Results344 neonates with SARS-CoV-2 infection received inpatient care; breakdown by dominant variant: 146 wildtype, 123 alpha, 57 delta and 18 omicron. Overall, 44.7% (153/342) neonates required respiratory support; short-term outcomes were good with 93.6% (322/344) of neonates discharged home. Eleven neonates died: seven unrelated to SARS-CoV-2 infection, four were attributed to neonatal SARS-CoV-2 infection (case fatality 4/344, 1.2% 95% CI 0.3% to 3.0%) of which three were born preterm due to maternal COVID-19. More neonates were born very preterm (23/54) and required invasive ventilation (27/57) when delta variant was predominant, and all four SARS-CoV-2-related deaths occurred in this period.ConclusionsInpatient care for neonates with SARS-CoV-2 was uncommon. Although rare, severe neonatal illness was more common during the delta variant period, potentially reflecting more severe maternal disease and associated preterm birth.Trial registration number ISRCTN60033461.

Although knowledge of molecular biology and cellular physiology has advanced at a rapid pace, much remains to be learned about delivering chemotherapy and antibodies across the blood-brain barrier (BBB) for the diagnosis and treatment of central nervous system (CNS) disease. A meeting, partially funded by an NIH R13 grant, was convened to discuss the state of the science, current knowledge gaps, and future directions in the delivery of drugs and proteins to the CNS, for the treatment of primary and metastatic brain tumors. Meeting topics included CNS metastases and the BBB, and chemoprotection and chemoenhancement in CNS disorders. The discussions regarding CNS metastases generated possibilities of chemoprotection as a means not only to decrease treatment-related toxicity but also to increase chemotherapy dose intensity. The increasing incidence of sanctuary brain metastasis from breast cancer, in part due to the difficulty of monoclonal antibodies (mAbs) such as herceptin to cross the BBB, was one of the most salient \"take home\" messages of the meeting.