Alagille syndrome was initially described as the association of five major features: paucity of interlobular bile ducts, peripheral pulmonary artery stenosis, butterfly-like vertebral arch defect, posterior embryotoxon, and a peculiar facies. Because of the variable expressivity of the syndrome, individuals presenting with three of the five main features are considered to have AGS. There is a general agreement for considering that genetic testing is not necessary for the diagnosis of AGS which relies mainly on clinical examination. But genetic testing of the proband is mandatory before genetic counseling. This testing includes karyotyping and FISH looking for deletion, and if negative sequencing of JAG1 gene coding sequence exists. In all cases, due to high variable expressivity, it is impossible to predict the number and the severity of the features in affected sib or offspring of a proband. JAG1 mutations are identified in 70% of AGS patients, although alteration outside the coding sequence is still possible, involvement of other components of Notch signaling pathway either as another disease-causing gene or as a modifier is very likely and is under study.
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The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.