British population history has been shaped by a series of immigrations, including the early Anglo-Saxon migrations after 400 CE. It remains an open question how these events affected the genetic composition of the current British population. Here, we present whole-genome sequences from 10 individuals excavated close to Cambridge in the East of England, ranging from the late Iron Age to the middle Anglo-Saxon period. By analysing shared rare variants with hundreds of modern samples from Britain and Europe, we estimate that on average the contemporary East English population derives 38% of its ancestry from Anglo-Saxon migrations. We gain further insight with a new method, rarecoal, which infers population history and identifies fine-scale genetic ancestry from rare variants. Using rarecoal we find that the Anglo-Saxon samples are closely related to modern Dutch and Danish populations, while the Iron Age samples share ancestors with multiple Northern European populations including Britain.
The present study indicates that the imminent change of tar yields in the European Union to comply with an upper limit of 12 mg/cigarette will not increase (and may somewhat decrease) the incidence of myocardial infarction, unless they indirectly help perpetuate tobacco use. Even low tar cigarettes still greatly increase rates of myocardial infarction, however, especially among people in their 30s, 40s, and 50s, and far more risk is avoided by not smoking than by changing from one type of cigarette to another.
British population history has been shaped by a series of immigrations and internal movements, including the early Anglo--Saxon migrations following the breakdown of the Roman administration after 410CE. It remains an open question how these events affected the genetic composition of the current British population. Here, we present whole--genome sequences generated from ten ancient individuals found in archaeological excavations close to Cambridge in the East of England, ranging from 2,300 until 1,200 years before present (Iron Age to Anglo--Saxon period). We use present--day genetic data to characterize the relationship of these ancient individuals to contemporary British and other European populations. By analyzing the distribution of shared rare variants across ancient and modern individuals, we find that today's British are more similar to the Iron Age individuals than to most of the Anglo--Saxon individuals, and estimate that the contemporary East English population derives 30% of its ancestry from Anglo--Saxon migrations, with a lower fraction in Wales and Scotland. We gain further insight with a new method, rarecoal, which fits a demographic model to the distribution of shared rare variants across a large number of samples, enabling fine scale analysis of subtle genetic differences and yielding explicit estimates of population sizes and split times. Using rarecoal we find that the ancestors of the Anglo--Saxon samples are closest to modern Danish and Dutch populations, while the Iron Age samples share ancestors with multiple Northern European populations including Britain.
ObjectiveLeukaemia is the most common cancer of childhood, accounting for a third of cases. In order to assist clinicians in its early detection, we systematically reviewed all existing data on its clinical presentation and estimated the frequency of signs and symptoms presenting at or prior to diagnosis.DesignWe searched MEDLINE and EMBASE for all studies describing presenting features of leukaemia in children (0–18 years) without date or language restriction, and, when appropriate, meta-analysed data from the included studies.ResultsWe screened 12 303 abstracts for eligibility and included 33 studies (n=3084) in the analysis. All were cohort studies without control groups. 95 presenting signs and symptoms were identified and ranked according to frequency. Five features were present in >50% of children: hepatomegaly (64%), splenomegaly (61%), pallor (54%), fever (53%) and bruising (52%). An additional eight features were present in a third to a half of children: recurrent infections (49%), fatigue (46%), limb pain (43%), hepatosplenomegaly (42%), bruising/petechiae (42%), lymphadenopathy (41%), bleeding tendency (38%) and rash (35%). 6% of children were asymptomatic on diagnosis.ConclusionsOver 50% of children with leukaemia have palpable livers, palpable spleens, pallor, fever or bruising on diagnosis. Abdominal symptoms such as anorexia, weight loss, abdominal pain and abdominal distension are common. Musculoskeletal symptoms such as limp and joint pain also feature prominently. Children with unexplained illness require a thorough history and focused clinical examination, which should include abdominal palpation, palpation for lymphadenopathy and careful scrutiny of the skin. Occurrence of multiple symptoms and signs should alert clinicians to possible leukaemia.
ObjectivesTo investigate the prehospital presentation of paediatric leukaemia and identify the disease and non-disease related factors which facilitate or impede diagnosis.DesignThematic analysis of qualitative semistructured interviews.SettingOne tertiary referral centre in Southern England.Participants21 parents and 9 general practitioners (GPs) of 18 children (<18-year-old) with a new diagnosis of acute leukaemia.ResultsThe majority of children were first seen by GPs before the characteristic signs and symptoms of leukaemia had developed. In their absence, behavioural cues such as the child becoming apathetic or ‘not themselves’ often triggered parents to seek medical help. Most GPs were unclear about the nature and severity of the child's presentation: then, safety netting, thorough history-taking and examination, and reliance on contextual information about the parents or from prior hospital paediatrics experience were used to manage diagnostic uncertainty. The nature of the doctor–parent relationship helped and hindered the diagnostic pathway. GPs’ prior perceptions of parents as being ‘sensible’ or ‘worriers’ influenced how gravely they treated parental concerns, with ‘worriers’ being taken less seriously. Some parents believed GPs failed to listen to their anxieties and discounted their expert knowledge of their child. Specific delay factors included lack of continuity of GP; some GPs’ reluctance to take blood from children; and some parents feeling unable to voice effectively their concerns.ConclusionsThe presentation of paediatric leukaemia in primary care differs from that described in many hospital studies, with greater diversity and intermittency of symptoms, and the frequent absence of ‘red flags’ of serious illness. A wide range of non-disease related factors potentially delay the diagnosis of paediatric leukaemia, including tensions in the doctor–patient relationship and the doctors’ cognitive biases. The identification and attempted modification of these factors may minimise diagnostic delay more successfully than raising awareness of ‘red flags’ of disease.
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