102 research outputs found

    ATRX mutation in two adult brothers with non-specific moderate intellectual disability identified by exome sequencing

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    In this report, we describe two adult brothers affected by moderate non-specific intellectual disability (ID). They showed minor facial anomalies, not clearly ascribable to any specific syndromic patterns, microcephaly, brachydactyly and broad toes. Both brothers presented seizures. Karyotype, subtelomeric and FMR1 analysis were normal in both cases. We performed array-CGH analysis that revealed no copy-number variations potentially associated with ID. Subsequent exome sequence analysis allowed the identification of the ATRX c.109C>T (p.R37X) mutation in both the affected brothers. Sanger sequencing confirmed the presence of the mutation in the brothers and showed that the mother is a healthy carrier. Mutations in the ATRX gene cause the X-linked alpha thalassemia/mental retardation (ATR-X) syndrome (MIM #301040), a severe clinical condition usually associated with profound ID, facial dysmorphism and alpha thalassemia. However, the syndrome is clinically heterogeneous and some mutations, including the c.109C>T, are associated with a broad phenotypic spectrum, with patients displaying a less severe phenotype with only mild-moderate ID. In the case presented here, exome sequencing provided an effective strategy to achieve the molecular diagnosis of ATR-X syndrome, which otherwise would have been difficult to consider due to the mild non-specific phenotype and the absence of a family history with typical severe cases

    Congenital midline cervical cleft: clinical approach to a congenital anterior neck defect

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    Numerous malformations can affect the anterior part of the neck presenting at birth as a real diagnostic challenge for the pediatrician or the primary care physician who initially evaluate the baby. Congenital midline cervical cleft represents a rare defect of the midline neck, which is sometimes wrongly diagnosed as a thyroglossal duct anomaly, dermoid cyst, branchial cleft anomaly or "birthmark". A prompt clinical diagnosis and surgical treatment during early infancy are essential to ensure both functional and aesthetic outcome. We report on a case of a female neonate with a midline cervical cleft diagnosed immediately after birth. The main features of other congenital anomalies of the anterior neck are also discussed referring to their embryologic origin

    Melorheostosis and Osteopoikilosis Clinical and Molecular Description of an Italian Case Series

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    Melorheostosis (MEL) is an uncommon, sclerosing disease, characterised by hyperostosis of long bones, resembling the flowing of candle wax. The disease is sporadic and the pathogenesis is still poorly understood. Occasionally, the same family can include individuals with MEL and Osteopoikilosis (OPK), a disease characterised by multiple round foci of increased bone density. LEMD3 gene mutations are related to OPK and Buschke\u2013Ollendorff Syndrome, a genetic condition in which an association between MEL, OPK and skin lesions is observed. In rare cases, LEMD3 mutations and recently mosaic MAP2K1 gene mutations have been correlated to MEL suggesting that somatic mosaicism could be causative of the disease. In this study, we described the clinical, radiological and molecular findings of 19 individuals with MEL and 8 with OPK and compared the results to the medical literature. The molecular analyses of this case series corroborate the available data in the medical literature, indicating that LEMD3 germline mutations are not a major cause of isolated MEL and reporting five further cases of OPK caused by LEMD3 germline mutations

    Study of the lineshape of the chi(c1) (3872) state

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    A study of the lineshape of the chi(c1) (3872) state is made using a data sample corresponding to an integrated luminosity of 3 fb(-1) collected in pp collisions at center-of-mass energies of 7 and 8 TeV with the LHCb detector. Candidate chi(c1)(3872) and psi(2S) mesons from b-hadron decays are selected in the J/psi pi(+)pi(-) decay mode. Describing the lineshape with a Breit-Wigner function, the mass splitting between the chi(c1 )(3872) and psi(2S) states, Delta m, and the width of the chi(c1 )(3872) state, Gamma(Bw), are determined to be (Delta m=185.598 +/- 0.067 +/- 0.068 Mev,)(Gamma BW=1.39 +/- 0.24 +/- 0.10 Mev,) where the first uncertainty is statistical and the second systematic. Using a Flatte-inspired model, the mode and full width at half maximum of the lineshape are determined to be (mode=3871.69+0.00+0.05 MeV.)(FWHM=0.22-0.04+0.13+0.07+0.11-0.06-0.13 MeV, ) An investigation of the analytic structure of the Flatte amplitude reveals a pole structure, which is compatible with a quasibound D-0(D) over bar*(0) state but a quasivirtual state is still allowed at the level of 2 standard deviations

    Measurement of the CKM angle γγ in B±DK±B^\pm\to D K^\pm and B±Dπ±B^\pm \to D π^\pm decays with DKS0h+hD \to K_\mathrm S^0 h^+ h^-

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    A measurement of CPCP-violating observables is performed using the decays B±DK±B^\pm\to D K^\pm and B±Dπ±B^\pm\to D \pi^\pm, where the DD meson is reconstructed in one of the self-conjugate three-body final states KSπ+πK_{\mathrm S}\pi^+\pi^- and KSK+KK_{\mathrm S}K^+K^- (commonly denoted KSh+hK_{\mathrm S} h^+h^-). The decays are analysed in bins of the DD-decay phase space, leading to a measurement that is independent of the modelling of the DD-decay amplitude. The observables are interpreted in terms of the CKM angle γ\gamma. Using a data sample corresponding to an integrated luminosity of 9fb19\,\text{fb}^{-1} collected in proton-proton collisions at centre-of-mass energies of 77, 88, and 13TeV13\,\text{TeV} with the LHCb experiment, γ\gamma is measured to be (68.75.1+5.2)\left(68.7^{+5.2}_{-5.1}\right)^\circ. The hadronic parameters rBDKr_B^{DK}, rBDπr_B^{D\pi}, δBDK\delta_B^{DK}, and δBDπ\delta_B^{D\pi}, which are the ratios and strong-phase differences of the suppressed and favoured B±B^\pm decays, are also reported

    Helium identification with LHCb

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    The identification of helium nuclei at LHCb is achieved using a method based on measurements of ionisation losses in the silicon sensors and timing measurements in the Outer Tracker drift tubes. The background from photon conversions is reduced using the RICH detectors and an isolation requirement. The method is developed using pp collision data at √(s) = 13 TeV recorded by the LHCb experiment in the years 2016 to 2018, corresponding to an integrated luminosity of 5.5 fb-1. A total of around 105 helium and antihelium candidates are identified with negligible background contamination. The helium identification efficiency is estimated to be approximately 50% with a corresponding background rejection rate of up to O(10^12). These results demonstrate the feasibility of a rich programme of measurements of QCD and astrophysics interest involving light nuclei

    Measurement of forward charged hadron flow harmonics in peripheral PbPb collisions at √sNN = 5.02 TeV with the LHCb detector

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    Flow harmonic coefficients, v n , which are the key to studying the hydrodynamics of the quark-gluon plasma (QGP) created in heavy-ion collisions, have been measured in various collision systems and kinematic regions and using various particle species. The study of flow harmonics in a wide pseudorapidity range is particularly valuable to understand the temperature dependence of the shear viscosity to entropy density ratio of the QGP. This paper presents the first LHCb results of the second- and the third-order flow harmonic coefficients of charged hadrons as a function of transverse momentum in the forward region, corresponding to pseudorapidities between 2.0 and 4.9, using the data collected from PbPb collisions in 2018 at a center-of-mass energy of 5.02 TeV . The coefficients measured using the two-particle angular correlation analysis method are smaller than the central-pseudorapidity measurements at ALICE and ATLAS from the same collision system but share similar features

    Curvature-bias corrections using a pseudomass method

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    Momentum measurements for very high momentum charged particles, such as muons from electroweak vector boson decays, are particularly susceptible to charge-dependent curvature biases that arise from misalignments of tracking detectors. Low momentum charged particles used in alignment procedures have limited sensitivity to coherent displacements of such detectors, and therefore are unable to fully constrain these misalignments to the precision necessary for studies of electroweak physics. Additional approaches are therefore required to understand and correct for these effects. In this paper the curvature biases present at the LHCb detector are studied using the pseudomass method in proton-proton collision data recorded at centre of mass energy √(s)=13 TeV during 2016, 2017 and 2018. The biases are determined using Z→μ + μ - decays in intervals defined by the data-taking period, magnet polarity and muon direction. Correcting for these biases, which are typically at the 10-4 GeV-1 level, improves the Z→μ + μ - mass resolution by roughly 18% and eliminates several pathological trends in the kinematic-dependence of the mean dimuon invariant mass

    Study of CP violation in B0 → DK⋆(892)0 decays with D → Kπ(ππ), ππ(ππ), and KK final states

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    A measurement of CP-violating observables associated with the interference of B0 → D0K⋆ (892)0 and B0 → D¯ 0K⋆ (892)0 decay amplitudes is performed in the D0 → K∓π ±(π +π −), D0 → π +π −(π +π −), and D0 → K+K− fnal states using data collected by the LHCb experiment corresponding to an integrated luminosity of 9 fb−1 . CP-violating observables related to the interference of B0 s → D0K¯ ⋆ (892)0 and B0 s → D¯ 0K¯ ⋆ (892)0 are also measured, but no evidence for interference is found. The B0 observables are used to constrain the parameter space of the CKM angle γ and the hadronic parameters r DK⋆ B0 and δ DK⋆ B0 with inputs from other measurements. In a combined analysis, these measurements allow for four solutions in the parameter space, only one of which is consistent with the world average

    Study of the doubly charmed tetraquark T+cc

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    Quantum chromodynamics, the theory of the strong force, describes interactions of coloured quarks and gluons and the formation of hadronic matter. Conventional hadronic matter consists of baryons and mesons made of three quarks and quark-antiquark pairs, respectively. Particles with an alternative quark content are known as exotic states. Here a study is reported of an exotic narrow state in the D0D0π+ mass spectrum just below the D*+D0 mass threshold produced in proton-proton collisions collected with the LHCb detector at the Large Hadron Collider. The state is consistent with the ground isoscalar T+cc tetraquark with a quark content of ccu⎯⎯⎯d⎯⎯⎯ and spin-parity quantum numbers JP = 1+. Study of the DD mass spectra disfavours interpretation of the resonance as the isovector state. The decay structure via intermediate off-shell D*+ mesons is consistent with the observed D0π+ mass distribution. To analyse the mass of the resonance and its coupling to the D*D system, a dedicated model is developed under the assumption of an isoscalar axial-vector T+cc state decaying to the D*D channel. Using this model, resonance parameters including the pole position, scattering length, effective range and compositeness are determined to reveal important information about the nature of the T+cc state. In addition, an unexpected dependence of the production rate on track multiplicity is observed
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