rs3865418 — NEDD4L

NEDD4L — The Kidney's Sodium Channel Gatekeeper

Every heartbeat depends on the right amount of sodium in the blood. The kidneys are the master regulators of that balance, and NEDD4L is one of their most critical molecular gatekeepers. This gene encodes an E3 ubiquitin ligase¹¹ E3 ubiquitin ligase
an enzyme that tags specific proteins for degradation by attaching ubiquitin chains to them. Its primary target in the kidney collecting duct is the epithelial sodium channel (ENaC)²² epithelial sodium channel (ENaC)
the principal channel through which sodium is reclaimed from urine back into the bloodstream. By ubiquitinating ENaC subunits, NEDD4L controls how many active channels are present at the cell surface — and therefore how much sodium the kidney retains.

The rs3865418 variant sits within an intron of NEDD4L and tags a haplotype associated with reduced ubiquitin-ligase efficiency toward ENaC. When NEDD4L activity is diminished, more ENaC channels remain at the kidney tubule surface, sodium reabsorption increases, and blood pressure rises — a mechanism remarkably similar to Liddle's syndrome³³ Liddle's syndrome
a rare monogenic hypertension caused by ENaC PY-motif mutations that prevent NEDD4L binding entirely, but acting through a subtler, common-variant mechanism.

The Mechanism

NEDD4L recognizes ENaC through its WW domains, which bind PY motifs on the β- and γ-ENaC subunits⁴⁴ WW domains, which bind PY motifs on the β- and γ-ENaC subunits
creating a molecular handshake that initiates ubiquitin transfer and channel endocytosis. Once ubiquitinated, ENaC is internalized and degraded, reducing sodium reabsorption. This process is under tight hormonal control: aldosterone and the kinase SGK1 phosphorylate NEDD4L, causing it to bind 14-3-3 proteins⁵⁵ aldosterone and the kinase SGK1 phosphorylate NEDD4L, causing it to bind 14-3-3 proteins
sequestering it away from ENaC and temporarily allowing greater sodium reabsorption in response to volume depletion. The rs3865418 T allele tags a haplotype where baseline NEDD4L-ENaC interaction is less efficient, shifting this equilibrium toward sustained sodium retention even under normal salt intake. NEDD4L also regulates NCC (the distal tubule Na⁺-Cl⁻ cotransporter)⁶⁶ NCC (the distal tubule Na⁺-Cl⁻ cotransporter)
another major renal sodium transporter whose overactivity compounds ENaC-mediated hypertension, and knockout studies confirm that renal NEDD4L loss alone causes salt-sensitive hypertension in animal models.

The Evidence

Direct evidence for rs3865418 in humans comes from several Asian population studies. Wen et al. 2008⁷⁷ Wen et al. 2008
Two polymorphisms in NEDD4L gene and essential hypertension in Chinese Hans. Clin Exp Hypertens 2008 conducted a population-based case-control study in Chinese Han individuals and found that the T allele at rs3865418 was associated with significantly higher diastolic blood pressure under a dominant model (p=0.009). The sex-stratified analysis by Liang et al. 2014⁸⁸ Liang et al. 2014
Gender difference in association of NEDD4L gene variants among southern Han Chinese with essential hypertension. Clin Exp Hypertens 2014 in 1,898 participants found rs3865418 associated with hypertension in men (OR=0.71, p=0.009), revealing a gene-by-sex interaction. A review of NEDD4L in cardiovascular disease by Li et al. 2022⁹⁹ Li et al. 2022
Research progress of Nedd4L in cardiovascular diseases. Cell Death Discovery 2022 further confirmed rs3865418 association with hypertension in American and Greek white populations, suggesting the effect is not limited to Asian cohorts.

In the broader NEDD4L context, a large Korean cohort study of 8,842 individuals¹⁰¹⁰ large Korean cohort study of 8,842 individuals
Jin et al. Kidney Blood Press Res 2010 identified 13 SNPs in SCNN1B, SCNN1G, and NEDD4L genes linked to hypertension in case-control analysis, supporting the entire ENaC-NEDD4L regulatory axis as a polygenic determinant of blood pressure. NEDD4L variants conferring salt sensitivity have also been linked to a hazard ratio for cardiovascular disease of 1.13 (95% CI 1.02–1.25)¹¹¹¹ hazard ratio for cardiovascular disease of 1.13 (95% CI 1.02–1.25)
and coronary event risk of 1.20 in longitudinal analyses, indicating that the blood pressure effect translates into downstream cardiac events.

Practical Implications

The T allele tags impaired sodium channel degradation, making you genetically predisposed to salt-sensitive blood pressure responses. Unlike standard hypertension risk, this variant points specifically to the renal sodium-retention pathway — meaning dietary sodium intake is a particularly potent lever. Carriers of NEDD4L risk variants respond more dramatically to dietary salt restriction¹²¹² Carriers of NEDD4L risk variants respond more dramatically to dietary salt restriction
because their kidneys retain more sodium per unit of intake than average. Practical targets from clinical guidelines for salt-sensitive hypertension: dietary sodium below 1,500 mg/day (vs. the general 2,300 mg/day target) and potassium intake of 4,700 mg/day from food to promote natriuresis. Antihypertensive drug classes that target the aldosterone-ENaC axis — spironolactone, eplerenone (aldosterone antagonists), and amiloride (direct ENaC blocker)¹³¹³ spironolactone, eplerenone (aldosterone antagonists), and amiloride (direct ENaC blocker)
these drugs mechanistically counteract the NEDD4L-ENaC dysregulation at its downstream effector — are particularly rational choices for carriers who develop hypertension.

Interactions

rs3865418 belongs to a haplotype block with rs4149601¹⁴¹⁴ rs4149601
a coding variant in exon 1 of NEDD4L that alters isoform expression and is the most functionally characterized NEDD4L SNP. The two variants are often in linkage disequilibrium but have been studied independently in different populations. The rs4149601 G allele reduces ENaC ubiquitination directly; rs3865418 T appears to tag a related but distinct mechanism affecting isoform balance or regulatory efficiency. Carrying risk alleles at both positions would be expected to compound renal sodium retention, though direct compound-genotype data are limited. Other pathway partners include rs2288774 and rs2288775¹⁵¹⁵ rs2288774 and rs2288775
additional NEDD4L intronic variants associated with hypertension in Kazakh and Chinese populations, as well as ENaC subunit variants in SCNN1B and SCNN1G that lie downstream in the same sodium-reabsorption pathway.