ISABELLA RAMOS LIMA
Projetos de Pesquisa
Unidades Organizacionais
LIM/13 - Laboratório de Genética e Cardiologia Molecular, Hospital das Clínicas, Faculdade de Medicina
3 resultados
Resultados de Busca
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- Screening of ABCG5 and ABCG8 Genes for Sitosterolemia in a Familial Hypercholesterolemia Cascade Screening Program(2022) TADA, Mauricio Teruo; ROCHA, Viviane Zorzanelli; LIMA, Isabella Ramos; OLIVEIRA, Theo Gremen Mimary; CHACRA, Ana Paula; MINAME, Marcio Hiroshi; NUNES, Valeria Sutti; NAKANDAKARE, Edna Regina; CASTELO, Maria Helane Costa Gurgel; JANNES, Cinthia Elim; SANTOS, Raul D.; KRIEGER, Jose Eduardo; PEREIRA, Alexandre CostaBackground: Sitosterolemia is a rare autosomal recessive disorder caused by homozygous or compound heterozygous variants in ABCG5/ABCG8. The disease is characterized by increased plasma plant sterols. Small case series suggest that patients with sitosterolemia have wide phenotypic heterogeneity with great variability on either plasma cholesterol levels or development of atherosclerotic cardiovascular disease. The present study aims to characterize the prevalence and clinical features of sitosterolemia participating in a familial hypercholesterolemia genetic cascade screening program. Methods: From 443 familial hypercholesterolemia index cases, 260 were negative for familial hypercholesterolemia genes and were sequenced for the ABCG5/8 genes. Clinical and laboratory characteristics of affected individuals were determined. Results: Eight (3.1%) index cases were found to be homozygous or compound heterozygous variant for ABCG5/ABCG8 genes, confirming the genetic diagnosis of sitosterolemia. Screening their relatives led to the identification of 6 additional confirmed sitosterolemia cases (3 homozygous and 3 compound heterozygous variant) and 18 carriers (heterozygous). The mean age of identified sitosterolemia cases (n=14) was 37.2 +/- 19.8 years, 50% were females, and 78.6% (all adults) presented either clinical or subclinical atherosclerotic cardiovascular disease. As expected, affected individuals presented elevated plasma plant sterol levels (mean beta-Sitosterol and campesterol, respectively, 160.3 +/- 107.1 and 32.0 +/- 19.6 mu g/mL) and the highest plasma LDL (low-density lipoprotein)-cholesterol was 269.0 +/- 120.0 mg/dL (range: 122-521 mg/dL). LDL-cholesterol mean reduction with therapy among cases was 65%. Eighty-three percent (83%) of identified sitosterolemia patients presented hematologic abnormalities. Conclusions: Testing genes associated with sitosterolemia in the molecular routine workflow of a familial hypercholesterolemia cascade screening program allowed the precise diagnosis of sitosterolemia in a substantial number of patients with varying LDL-C levels and high incidence of early atherosclerotic cardiovascular disease and hematologic abnormalities.
- Genome-Wide Association of Proprotein Convertase Subtilisin/Kexin Type 9 Plasma Levels in the ELSA-Brasil Study(2021) BENSENOR, Isabela; PADILHA, Kallyandra; LIMA, Isabella Ramos; SANTOS, Raul Dias; LAMBERT, Gilles; RAMIN-MANGATA, Stephane; BITTENCOURT, Marcio S.; GOULART, Alessandra C.; SANTOS, Itamar S.; MILL, Jose G.; KRIEGER, Jose E.; LOTUFO, Paulo A.; PEREIRA, Alexandre C.Pharmacological inhibition of PCSK9 (proprotein convertase subtilisin/kexin type 9) is an established therapeutic option to treat hypercholesterolemia, and plasma PCSK9 levels have been implicated in cardiovascular disease incidence. A number of genetic variants within the PCSK9 gene locus have been shown to modulate PCSK9 levels, but these only explain a very small percentage of the overall PCSK9 interindividual variation. Here we present data on the genetic association structure between PCSK9 levels and genom-wide genetic variation in a healthy sample from the general population. We performed a genome-wide association study of plasma PCSK9 levels in a sample of Brazilian individuals enrolled in the Estudo Longitudinal de Saude do Adulto cohort (n=810). Enrolled individuals were free from cardiovascular disease, diabetes and were not under lipid-lowering medication. Genome-wide genotyping was conducted using the Axiom_PMRA.r3 array, and imputation was performed using the TOPMED multi-ancestry sample panel as reference. Total PCSK9 plasma concentrations were determined using the Quantikine SPC900 ELISA kit. We observed two genome-wide significant loci and seven loci that reached the pre-defined value of p threshold of 1x10(-6). Significant variants were near KCNA5 and KCNA1, and LINC00353. Genetic variation at the PCSK9 locus was able to explain approximately 4% of the overall interindividual variations in PCSK9 levels. Colocalization analysis using eQTL data suggested RWDD3, ATXN7L1, KCNA1, and FAM177A1 to be potential mediators of some of the observed associations. Our results suggest that PCSK9 levels may be modulated by trans genetic variation outside of the PCSK9 gene and this may have clinical implications. Understanding both environmental and genetic predictors of PCSK9 levels may help identify new targets for cardiovascular disease treatment and contribute to a better assessment of the benefits of long-term PCSK9 inhibition.
- Familial hypercholesterolemia and cardiovascular disease in older individuals(2021) COUTINHO, Elaine R.; MINAME, Marcio H.; ROCHA, Viviane Z.; BITTENCOURT, Marcio S.; JANNES, Cinthia E.; TADA, Mauricio T.; LIMA, Isabella R.; SALGADO FILHO, Wilson; CHACRA, Ana P.; PEREIRA, Alexandre C.; KRIEGER, Jose E.; SANTOS, Raul D.Background and aims: Familial hypercholestemlemia (FH) is characterized by high LDL-cholesterol (LDL-C) and early atherosclerotic cardiovascular disease (ASCVD). With a lipid lowering therapy (LLT), most individuals with FH may have a longer ASCVD-free survival. However, there is scant data about older individuals with FH. Methods: We compared characteristics of genetically defined FH older individuals with age-matched non-FH counterparts. Results: From 4111 genotyped individuals, 462 older than 60 years were included (198 positive and 264 negative for FH variants). There were no differences regarding median age [%25; 75%] 66.0 (62.0; 71.0) and 66.0 (62.2; 71.0) years, p = 0.68 for FH and non-FH, respectively. In both groups, there was a higher frequency of females, however, there were more males in the FH group 37.4% vs. 24.2%, p = 0.002. No differences were seen between FH and non-FH in LLT use: 88.5% vs. 91.5%, p = 0.29. Despite a longer LLT duration in FH patients (with 11.0 (7.0; 20.0) vs. 7.0 (3.0; 13.0) years, p < 0.001), treatment was started late in both groups: at 54.0 (47.0; 61.0) and 59.0 (52.0; 64.0) years, p < 0.001, in FH and non-FH, respectively. FH had greater frequencies of previous and early ASCVD (40.9% vs. 27.3%, p = 0.002, and 22.2% vs. 9.0%, p < 0.001). In FH, male sex [HR (95%C01 2.67 (1.50-4.73), p = 0.001, and LLT onset age 0.96 (0.93-0.99), p = 0.009, were independently associated with ASCVD. Conclusions: Among hypercholesterolemic older individuals participating in a cascade screening program, the genetic diagnosis of FH was associated with higher ASCVD rates, emphasizing the relevance of a monogenic defect as the cause of long-lasting hypercholesterolemia and ASCVD risk, particularly in men.