X-chromosome variants are associated with aldosterone producing adenomas

Aldosterone-producing adenomas (APAs) are a major cause of primary aldosteronism (PA) and are characterized by constitutively producing aldosterone, which leads to hypertension. Several mutations have been identified in ion channels or ion channel-associated genes that result in APAs. To date, no studies have used a genome-wide association study (GWAS) approach to search for predisposing loci for APAs. Thus, we investigated Scandinavian APA cases (n=35) and Swedish controls (n=60) in a GWAS and discovered a susceptibility locus on chromosome Xq13.3 (rs2224095, OR=7.9, 95% CI=2.8-22.4, P=1x10(-7)) in a 4-Mb region that was significantly associated with APA. Direct genotyping of sentinel SNP rs2224095 in a replication cohort of APAs (n=83) and a control group (n=740) revealed persistently strong significance (OR=6.1, 95% CI=3.5-10.6, p<0.0005). We sequenced an adjacent gene, MAGEE1, of the sentinel SNP and identified a rare variant in one APA, p.Gly327Glu, which is complementary to other mutations in our primary cohort. Expression quantitative trait loci (eQTL) were investigated on the X-chromosome, and 24 trans-eQTL were identified. Some of the genes identified by trans-eQTL point towards a novel mechanistic explanation for the association of the SNPs with APAs. In conclusion, our study provides further insights into the genetic basis of APAs.

Automated summary

This study identified a susceptibility locus on chromosome Xq13.3 associated with APAs using a GWAS approach. Direct genotyping of a sentinel SNP in a replication cohort showed strong significance, and sequencing of an adjacent gene revealed a rare variant. Investigation of expression quantitative trait loci provided insights into the genetic basis and potential novel mechanistic explanations for the association of the SNPs with APAs.