138 research outputs found
Maxillo-Facial Morphology in Beckwith-Wiedemann Syndrome: A Preliminary Study on (epi)Genotype-Phenotype Association in Caucasians
Beckwith–Wiedemann syndrome (BWS) is a congenital overgrowth disorder caused by various (epi)genetic alterations affecting the expression of genes on chromosome 11p15. Cardinal features include abdominal wall defects, macroglossia, and cancer predisposition. Several (epi)genotype–phenotype associations were described so far, but specific studies on the evolution over time of maxillo-facial phenotype in the molecular subtypes still are scanty. The aim of this cross-sectional study was to associate maxillo-facial morphology and growth pattern with genoype in 25 Caucasian children with BWS and macroglossia. Twelve patients experienced a loss of metilation at imprinting center 2 (IC2-LoM), five had mosaic paternal uniparental isodisomy of chromosome 11 (UPD(11)pat), and eight were negative. A more marked tongue enlargement was detected in patients with IC2-LoM and negative genotype, while UPD(11)pat children showed mild macroglossia (p = 0.048). A cluster analysis did not demonstrate any specific relationship between (epi)genotype and maxillo-facial phenotype, but separated BWS patients based on their cephalometric characteristics. Children with IC2-LoM or negative genotype displayed hyperdivergence values > 30°, clockwise growth tendency, and skeletal class II into the same cluster. They had a negative prognostic score. These preliminary data suggest the need for developing individualized protocols for early monitoring of the craniofacial growth in such patients
Quantitative constraints on the gluon distribution function in the proton from collider isolated-photon data
The impact of isolated-photon data from proton-(anti)proton collisions at
RHIC, SppbarS, Tevatron and LHC energies, on the parton distribution functions
of the proton is studied using a recently developed Bayesian reweighting
method. The impact on the gluon density of the 35 existing isolated-gamma
measurements is quantified using next-to-leading order (NLO) perturbative QCD
calculations complemented with the NNPDF2.1 parton densities. The NLO
predictions are found to describe well most of the datasets from 200 GeV up to
7 TeV centre-of-mass energies. The isolated-photon spectra recently measured at
the LHC are precise enough to constrain the gluon distribution and lead to a
moderate reduction (up to 20%) of its uncertainties around fractional momenta
x~0.02. As a particular case, we show that the improved gluon density reduces
the PDF uncertainty for the Higgs boson production cross section in the
gluon-fusion channel by more than 20% at the LHC. We conclude that present and
future isolated-photon measurements constitute an interesting addition to
coming global PDF analyses.Comment: 30 pages, 20 figures. Few minor changes to match the published NPB
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