Browsing by Author "Rothhammer, Francisco"

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    Attention deficit hyperactivity disorder in Aymara children
    (SOC MEDICA SANTIAGO, 2012) Carrasco, Ximena; Daiber, Francisca; Rothhammer, Paula; Huerta, Daniela; Andrade, Claudia; Opazo, Patricia; Paz Lagos, Liza; Rothhammer, Francisco; Aboitiz, Francisco
    Background: The assessment of Attentional Deficit Hyperactivity Disorder (ADHD) among ethnic groups may reveal environmental or cultural variables that influence the appearance of this disorder. Aim: To assess the presence and characteristics of ADHD in two communities of the inland Arica valleys (Azapa and Lluta), where the Aymara population predominates. Material and Methods: Starting from a screening based on the Conner's test, we evaluated 79 children aged 8 to 13 years. Sixty children were of Aymara origin and 19 children were of non-Aymara origin. Twenty Aymara and 9 non-Aymara children had ADHD. They were compared with a group of patients from Santiago, Chile (110 children) that were previously assessed. Results: Patients from Azapa/Lluta displayed similar characteristics to those from Santiago. However the former had significantly less psychiatric comorbidities than the latter. On the other hand, the non-Aymara subgroup of Azapa/Lluta displayed an increased rate of comorbidities and was exclusively of the combined subtype, although their sample size is too small to draw strong conclusions. Conclusions: Although we cannot dismiss biological variables, the importance of family values and the respect to authorities may be protective factors for ADHD, associated to Aymara culture. Our findings suggest that the clinical characteristics of ADHD are not uniform among ethnic groups and cultures. The relative contribution of environmental and genetic factors in this variability remain to be determined. (Rev Med Chile 2012; 140: 1409-1416).
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    DRD4 dopamine receptor alleles in Chilean students of different ethnic origin and its relation with the risk for attention deficit/hyperactivity disorder
    (SOC MEDICA SANTIAGO, 2012) Rothhammer, Paula; Paz Lagos, Liza; Espinosa Parrilla, Yolanda; Aboitiz, Francisco; Rothhammer, Francisco
    Background: Worldwide diversity of alleles of D4 receptor gene (DRD4), linked to attention deficit hyperactivity disorder (ADHD), is mostly the result of length and single nucleotide polymorphisms in a 48-bp tandem repeat (VNTR). Alleles containing from two (2R) to eleven (11R) repeats have been identified. The most common are 4R, 7R and 2R. Aim: To study the association of ADHD risk with DRD4 genotypes in Chilean students. Subjects and Methods: ADHD risk data were obtained through the abbreviated Conner's Scale for School Teachers in 66 Aymara children (11 cases and 55 controls), 91 Rapa-Nui children (60 cases ad 31 controls) and 96 children from a mixed urban population from Santiago (51 cases and 45 controls). DNA extracted from saliva was amplified by polymerase chain reaction (PCR) to genotype the DRD4 VNTR. Results: The distribution of DRD4 alleles reveals that, beneath the 4R allele, 7R exhibits the second highest frequencies in Aymara and Santiago children. In Polynesian children, 2R ranks after 4R. A statistically significant association between ADHD risk and 2R/4R genotype was identified in Polynesian children (p < 0.05; odds ratio = 3.7). Conclusions: Different DRD4 genotypes are associated with ADHD phenotype in Chilean populations, probably as a consequence of their initial colonization history. (Rev Med Chile 2012; 140: 1276-1281).
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    Gallbladder Cancer Risk and Indigenous South American Mapuche Ancestry: Instrumental Variable Analysis Using Ancestry-Informative Markers
    (2023) Zollner, Linda; Boekstegers, Felix; Barahona Ponce, Carol; Scherer, Dominique; Marcelain, Katherine; Gárate-Calderón, Valentina; Waldenberger, Melanie; Morales Mejías, Erik; Rojas, Armando; Muñoz, César; Retamales, Javier; Toro, Gonzalo De; Vera Kortmann, Allan; Barajas, Olga; Rivera, María Teresa; Cortés, Analía; Loader, Denisse; Saavedra, Javiera; Gutiérrez, Lorena; Ortega, Alejandro; Bertrán, María Enriqueta; Bartolotti, Leonardo; Gabler, Fernando; Campos, Mónica; Alvarado, Juan; Moisán, Fabricio; Spencer, María Loreto; Nervi Nattero, Bruno; Carvajal-Hausdorf, Daniel; Losada, Héctor; Almau, Mauricio; Fernández, Plinio; Olloquequi, Jordi; Carter, Alice R.; Miquel P., Juan Francisco; Bustos, Bernabé I.; Fuentes Guajardo, Macarena; Gonzalez-Jose, Rolando; Bortolini, Maria Cátira; Acuña-Alonzo, Victor; Gallo, Carla; Ruiz Linares, Andrés; Rothhammer, Francisco; Bermejo, Justo Lorenzo
    A strong association between the proportion of indigenous South American Mapuche ancestry and the risk of gallbladder cancer (GBC) has been reported in observational studies. Chileans show the highest incidence of GBC worldwide, and the Mapuche are the largest indigenous people in Chile. We set out to assess the confounding-free effect of the individual proportion of Mapuche ancestry on GBC risk and to investigate the mediating effects of gallstone disease and body mass index (BMI) on this association. Genetic markers of Mapuche ancestry were selected based on the informativeness for assignment measure, and then used as instrumental variables in two-sample Mendelian randomization analyses and complementary sensitivity analyses. Results suggested a putatively causal effect of Mapuche ancestry on GBC risk (inverse variance-weighted (IVW) risk increase of 0.8% per 1% increase in Mapuche ancestry proportion, 95% CI 0.4% to 1.2%, p = 6.7 × 10−5) and also on gallstone disease (3.6% IVW risk increase, 95% CI 3.1% to 4.0%), pointing to a mediating effect of gallstones on the association between Mapuche ancestry and GBC. In contrast, the proportion of Mapuche ancestry showed a negative effect on BMI (IVW estimate −0.006 kg/m2, 95% CI −0.009 to −0.003). The results presented here may have significant implications for GBC prevention and are important for future admixture mapping studies. Given that the association between the individual proportion of Mapuche ancestry and GBC risk previously noted in observational studies appears to be free of confounding, primary and secondary prevention strategies that consider genetic ancestry could be particularly efficient.
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    Intratask Variability As a Correlate for DRD4 and SLC6A3 Variants : A Pilot Study in ADHD
    (2015) Henríquez Henríquez, Marcela Patricia; Villarroel del Pino, Luis A.; Henríquez, Hugo; Zamorano, Francisco; Rothhammer, Francisco; Aboitiz, Francisco