Endocrine tumors such as aldosterone-producing adrenal adenomas (APAs), a cause of severe hypertension, feature constitutive hormone production and unrestrained cell proliferation; the mechanisms linking these events are unknown. We identify two recurrent somatic mutations in and near the selectivity filter of the potassium (K+) channel KCNJ5 that are present in 8 of 22 human APAs studied. Both produce increased sodium (Na+) conductance and cell depolarization, which in adrenal glomerulosa cells produces calcium (Ca2+) entry, the signal for aldosterone production and cell proliferation. Similarly, we identify an inherited KCNJ5 mutation that produces increased Na+ conductance in a Mendelian form of severe aldosteronism and massive bilateral adrenal hyperplasia. These findings explain pathogenesis in a subset of patients with severe hypertension and implicate loss of K+ channel selectivity in constitutive cell proliferation and hormone production.

Protein coding genes constitute only approximately 1% of the human genome but harbor 85% of the mutations with large effects on disease-related traits. Therefore, efficient strategies for selectively sequencing complete coding regions (i.e., ''whole exome'') have the potential to contribute to the understanding of rare and common human diseases. Here we report a method for whole-exome sequencing coupling Roche/NimbleGen whole exome arrays to the Illumina DNA sequencing platform. We demonstrate the ability to capture approximately 95% of the targeted coding sequences with high sensitivity and specificity for detection of homozygous and heterozygous variants. We illustrate the utility of this approach by making an unanticipated genetic diagnosis of congenital chloride diarrhea in a patient referred with a suspected diagnosis of Bartter syndrome, a renal salt-wasting disease. The molecular diagnosis was based on the finding of a homozygous missense D652N mutation at a position in SLC26A3 (the known congenital chloride diarrhea locus) that is virtually completely conserved in orthologues and paralogues from invertebrates to humans, and clinical follow-up confirmed the diagnosis. To our knowledge, whole-exome (or genome) sequencing has not previously been used to make a genetic diagnosis. Five additional patients suspected to have Bartter syndrome but who did not have mutations in known genes for this disease had homozygous deleterious mutations in SLC26A3. These results demonstrate the clinical utility of whole-exome sequencing and have implications for disease gene discovery and clinical diagnosis.Bartter syndrome ͉ congenital chloride diarrhea ͉ next-generation sequencing ͉ whole-exome sequencing ͉ personal genomes G enetic variation plays a major role in both Mendelian and non-Mendelian diseases. Among the approximately 2,600 Mendelian diseases that have been solved, the overwhelming majority are caused by rare mutations that affect the function of individual proteins; at individual Mendelian loci, approximately 85% of the disease-causing mutations can typically be found in the coding region or in canonical splice sites (1). For complex traits, genome-wide association studies have identified more than 250 common variants associated with risk alleles that contribute to a wide range of diseases (2, 3). To date, most of these impart small effects on disease risk (e.g., odds ratio of 1.2); moreover, even when extremely large studies have been performed, the vast majority of the genetic contribution to disease risk remain unexplained (4-6). These findings suggest that individually rare variants with relatively large effect may account for a large fraction of this missing trait variance. Indeed, studies addressing this question have documented the presence of individually rare variants with relatively large effect (7,8). Consistent with the Mendelian model, coding variants have proven to be prevalent sources of such rare variants.These considerations motivate implementation of robust approaches to sequencing complete c...

The effects of alleles in many genes are believed to contribute to common complex diseases such as hypertension. Whether risk alleles comprise a small number of common variants or many rare independent mutations at trait loci is largely unknown. We screened members of the Framingham Heart Study (FHS) for variation in three genes -SLC12A3 (NCCT), SLC12A1 (NKCC2) and KCNJ1 (ROMK)-causing rare recessive diseases featuring large reductions in blood pressure. Using comparative genomics, genetics, and biochemistry, we identified subjects with mutations proven or inferred to be functional. These mutations, all heterozygous and rare, produce clinically significant blood pressure reduction and protect from development of hypertension. Our findings implicate many rare alleles that alter renal salt handling in blood pressure variation in the general population, and identify alleles with health benefit that are nonetheless under purifying selection. These findings have implications for the genetic architecture of hypertension and other common complex traits.Correspondence to: Richard Lifton richard.lifton@yale.edu 203-737-4420 Howard Hughes Medical Institute, Yale University School of Medicine, TAC Room S341D, 1 Gilbert Street, New Haven, CT 06510, USA. Accession Numbers. GenBank mRNA sequences are as follows: NCCT/SLC12A3 (NM_000339); NKCC2/SLC12A1 (NM_000338); ROMK/KCNJ1 (NM_000220, NM_153764-7). GenBank protein sequences are as follows: SLC12A3 orthologs: Human (NP_000330), mouse (NP_062288), rat (NP_062218), rabbit (AAC33139), dog (XP_535292), cow (XP_871112), chicken (XP_414059), zebrafish (NP_001038545) and winter flounder (AAL26926); SLC12A1orthologs: Human (NP_000329), mouse (NP_899197), rat (NP_062007), rabbit (AAB03494), dog (XP_850426), chicken (XP_413814), zebrafish (NP_001002080) and Tetraodon (CAF99849); SLC12A1-3 invertebrate orthologs: S. purpuratus (XP_783014), C. elegans (NP_502704) and D. melanogaster (NP_648572); KCNJ1 orthologs: Human (NP_72245), mouse (NP_062633), rat (NP_058719), dog (XP_546403), chicken (XP_425795), cow (XP_585917), frog (AAH79788), zebrafish (XP_684541), fugu (ABB87033), C.elegans (NP_509138), S. purpuratus (XP_789112) and D. melanogaster (NP_651131); Other human paralogs: SLC12A2 (NP_001037), SLC12A4 (NP_005063), SLC12A5 (NP_065759), SLC12A6 (NP_005126) and SLC12A7 (NP_006589), KCNJ2 (NP_000882), KCNJ3 (NP_002230) KCNJ4 (NP_004972), KCNJ5 (NP_000881), KCNJ6 (NP_002231), KCNJ8 (NP_004973), KCNJ9 (NP_004974), KCNJ10 (NP_002232), KCNJ11 (NP_000516), KCNJ12 (NP_066292), KCNJ13 (NP_002233), KCNJ14 (NP_733838), KCNJ15 (NP_733933) and KCNJ16 (NP_733938). NIH Public AccessAuthor Manuscript Nat Genet. Author manuscript; available in PMC 2013 September 08. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author ManuscriptHypertension affects 1 billion people world-wide and is a major contributor to death from stroke, myocardial infarction, end-stage renal disease and congestive heart failure. Although epidemiologic studies have demonstrated high heritability of blood pressure...