Browsing by Author "González, P. A."

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    A de novo unequal cross-over mutation between CYP11B1 and CYP11B2 genes causes familial hyperaldosteronism type I
    (2010) Carvajal, C. A.; Stehr, C. B.; González, P. A.; Riquelme, E. M.; Montero, T.; Santos, M. J.; Kalergis, Alexis M.; Fardella, C. E.
    Familial hyperaldosteronism type I (FH-I) is an autosomal dominant disorder caused by an unequal cross-over of the gene encoding steroid 11β-hydroxylase (CYP11B1) and aldosterone synthase (CYP11B2), giving rise to a chimeric CYP11B1/CYP11B2 gene that displays aldosterone synthase activity regulated by ACTH instead of angiotensin II.To report an unprecedented case of a de novo unequal crossover mutation between CYP11B1 and CYP11B2 genes causing FH-I.The index case is a 45-yr-old Chilean male diagnosed with primary aldosteronism (PA). All family members were also studied: his biological parents, 1 brother, 6 sisters, 2 daughters, and 1 son. Plasma renin activity, serum aldosterone, and its ratio were measured in all patients. Genetic analyses were performed using long-extension PCR (XL-PCR), DNA sequencing and Southern blot methods.PA was diagnosed for the index case, 1 of his daughters, his son but not for his parents or siblings. XLPCR and Southern blotting demonstrated the presence of the chimeric CYP11B1/CYP11B2 gene solely in PA-affected subjects, suggesting a case of a de novo mutation. Sequence analysis showed the unequal cross-over CYP11B1/CYP11B2 at intron 2 (c.2600-273 CYP11B2). We also identified a polymorphism at the same intron (c.2600-145C>A CYP11B2) in the genome of the index case's father.We describe an unprecedented case of unequal cross-over mutation for the chimeric CYP11B1/CYP11B2 gene causing FH-I, which may be linked to a polymorphism in the index case's father germ line.
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    Study of null geodesics and their stability in Horndeski black holes
    (Springer Nature, 2025) Carvajal Araya, Diego Adolfo; González, P. A.; Olivares, Marco; Papantonopoulos, Eleftherios; Vásquez, Yerko
    We study the motion of particles in the background of a scalar–tensor theory of gravity in which the scalar field is kinetically coupled to the Einstein tensor, and we present the null geodesic structure for asymptotically flat, AdS, and dS Horndeski black holes, studying the effect of the cosmological constant on the orbits. Also, we consider three classical tests of gravity in the solar system, namely the bending of the light, the gravitational redshift, and the Shapiro time delay, in order to constraint the coupling parameters of the scalar field to gravity. Calculating the Lyapunov exponent, we explore the stability of these geodesics for various values of the cosmological constant.