Browsing by Author "Hernandez, Isabel"

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    Genetic Risk for Schizophrenia and Psychosis in Alzheimer Disease
    (Nature Publishing group, 2018-04) DeMichele-Sweet, Mary Ann A.; Weamer, Elise A.; Klei, Lambertus; Vrana, Dylan T.; Hollingshead, Deborah J.; Seltman, Howard J.; Sims, Rebecca; Foroud, Tatiana; Hernandez, Isabel; Moreno-Grau, Sonia; Tárraga, Lluís; Boada, Mercè; Ruiz, Agustin; Williams, Julie; Mayeux, Richard; Lopez, Oscar L.; Sibille, Etienne L.; Kamboh, M. Ilyas; Devlin, Bernie; Sweet, Robert A.; Medical and Molecular Genetics, School of Medicine
    Psychotic symptoms, defined as the occurrence of delusions or hallucinations, are frequent in Alzheimer Disease, affecting ~ 40% to 60% of individuals with AD (AD with psychosis, AD+P). In comparison to AD subjects without psychosis, AD+P subjects have more rapid cognitive decline and poor outcomes. Prior studies have estimated the heritability of psychosis in AD at 61%, but the underlying genetic sources of this risk are not known. We evaluated a Discovery Cohort of 2876 AD subjects with (N=1761) or without psychosis (N=1115). All subjects were genotyped using a custom genotyping array designed to evaluate SNPs with evidence of genetic association with AD+P and include SNPs affecting or putatively affecting risk for schizophrenia and Alzheimer disease. Results were replicated in an independent cohort of 2194 AD subjects with (N=734) or without psychosis (N=1460). We found that AD+P is associated with polygenic risk for a set of novel loci and inversely associated with polygenic risk for schizophrenia. Among the biologic pathways identified by the associations of schizophrenia SNPs with AD+P are endosomal trafficking, autophagy, and calcium channel signaling. These findings provide the first clear demonstration that AD+P is associated with common genetic variation. In addition, they provide an unbiased link between polygenic risk for schizophrenia and a lower risk of psychosis in AD. This provides an opportunity to leverage progress made in identifying the biologic effects of schizophrenia alleles to identify novel mechanisms protecting against more rapid cognitive decline and psychosis risk in AD.
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    Genome-wide association identifies the first risk loci for psychosis in Alzheimer disease
    (Springer Nature, 2021) DeMichele-Sweet, Mary Ann A.; Klei, Lambertus; Creese, Byron; Harwood, Janet C.; Weamer, Elise A.; McClain, Lora; Sims, Rebecca; Hernandez, Isabel; Moreno-Grau, Sonia; Tárraga, Lluís; Boada, Mercè; Alarcón-Martín, Emilio; Valero, Sergi; NIA-LOAD Family Based Study Consortium; Alzheimer’s Disease Genetics Consortium (ADGC); Liu, Yushi; Hooli, Basavaraj; Aarsland, Dag; Selbaek, Geir; Bergh, Sverre; Rongve, Arvid; Saltvedt, Ingvild; Skjellegrind, Håvard K.; Engdahl, Bo; Stordal, Eystein; Andreassen, Ole A.; Djurovic, Srdjan; Athanasiu, Lavinia; Seripa, Davide; Borroni, Barbara; Albani, Diego; Forloni, Gianluigi; Mecocci, Patrizia; Serretti, Alessandro; De Ronchi, Diana; Politis, Antonis; Williams, Julie; Mayeux, Richard; Foroud, Tatiana; Ruiz, Agustín; Ballard, Clive; Holmans, Peter; Lopez, Oscar L.; Kamboh, M. Ilyas; Devlin, Bernie; Sweet, Robert A.; Medical and Molecular Genetics, School of Medicine
    Psychotic symptoms, defined as the occurrence of delusions or hallucinations, are frequent in Alzheimer disease (AD with psychosis, AD + P). AD + P affects ~50% of individuals with AD, identifies a subgroup with poor outcomes, and is associated with a greater degree of cognitive impairment and depressive symptoms, compared to subjects without psychosis (AD - P). Although the estimated heritability of AD + P is 61%, genetic sources of risk are unknown. We report a genome-wide meta-analysis of 12,317 AD subjects, 5445 AD + P. Results showed common genetic variation accounted for a significant portion of heritability. Two loci, one in ENPP6 (rs9994623, O.R. (95%CI) 1.16 (1.10, 1.22), p = 1.26 × 10-8) and one spanning the 3'-UTR of an alternatively spliced transcript of SUMF1 (rs201109606, O.R. 0.65 (0.56-0.76), p = 3.24 × 10-8), had genome-wide significant associations with AD + P. Gene-based analysis identified a significant association with APOE, due to the APOE risk haplotype ε4. AD + P demonstrated negative genetic correlations with cognitive and educational attainment and positive genetic correlation with depressive symptoms. We previously observed a negative genetic correlation with schizophrenia; instead, we now found a stronger negative correlation with the related phenotype of bipolar disorder. Analysis of polygenic risk scores supported this genetic correlation and documented a positive genetic correlation with risk variation for AD, beyond the effect of ε4. We also document a small set of SNPs likely to affect risk for AD + P and AD or schizophrenia. These findings provide the first unbiased identification of the association of psychosis in AD with common genetic variation and provide insights into its genetic architecture.