8294 Association between gene mutations and DNA methylation of CYP11B2 in aldosterone-producing adenoma

Abstract

Abstract Disclosure: M. Kometani: None. R. Mizoguchi: None. M. Demura: None. K. Aiga: None. S. Konishi: None. D. Aono: None. S. Karashima: None. Y. Takeda: None. T. Yoneda: None. Context: Primary aldosteronism (PA) causes hypertension and cardiovascular complications. Recently, in aldosterone producing adenomas (APA), various genetic mutations have been identified. In addition, epigenetic mechanisms, such as DNA methylation, are also involved in excessive aldosterone production. Several studies have shown that aldosterone synthase (CYP11B2) is hypomethylated in APA. On the other hand, the relationship between specific genetic variants identified in APA and DNA methylation has not been fully clarified. Objective: To investigate the relationship between specific genetic mutations in APA and DNA methylation of CYP11B2. Methods: We analyzed 48 patients (female 23 cases) diagnosed with APA and treated between 2001 and 2022. First, Gene mutation analysis using next-generation sequencing was performed. KCNJ5, ATP1A1, ATP2B3, CACNA1D, and CACNA1H, which are known mutations in PA, and PRKACA, PRKA1A, GNAS, CTNNB1, and ARMC5, which are known mutations in Cushing’s syndrome, were evaluated. Next, DNA methylation analysis of the CYP11B2 promoter using pyrosequencing were performed using APA. We targeted three CpG regions near the transcription start site of CYP11B2. Results: The respective mean values for all patients were: age 52 years, systolic blood pressure 138 mmHg, diastolic blood pressure 87 mmHg, ARR 1,326, serum potassium level 3.4 mEq/L, and tumor diameter 15 mm. Genetic mutation analysis revealed KCNJ5 gene mutations in 33 of the 48 patients. Among the other cases, mutations in the CTNNB1 gene were found in three cases, mutations in the ATP1A1 gene in two cases, mutations in the CACNA1D gene in one case, and PRKACA gene mutations in one case. The remaining seven patients had no mutations in any of the analyzed genes. When DNA methylation of the promoter region of CYP11B2 was analyzed in APAs with and without mutations in KCNJ5, we found that in all three CpG regions, DNA methylation rate was significantly reduced in APAs with mutations in KCNJ5 gene (CpG1 22% vs. 30%, CpG2 42% vs. 73%, CpG3 47% vs. 75%, respectively). Conclusions: The most common genetic mutation in APA was the KCNJ5 mutation; APA with the KCNJ5 mutation had significantly lower methylation rates than CYP11B2. This suggests that genetic mutations in APA affect DNA methylation and result in hormone overproduction. Presentation: 6/3/2024