SLC9C2 encodes sodium/hydrogen exchanger 11 (NHE11), a member of the SLC9 Na+/H+ exchanger gene family that regulates cellular pH through ion transport across membranes 1. NHE11 exhibits testis and sperm-restricted expression, localizing distinctively to the acrosomal region of mature sperm heads in both rats and humans 2. The protein contains predicted NHE, voltage-sensing, and intracellular cyclic nucleotide-binding domains, suggesting it may modulate sperm head intracellular pH in response to membrane potential changes and cyclic nucleotide concentrations during sperm capacitation 2. While SLC9C2's physiological role remains largely uncharacterized 1, emerging evidence indicates disease relevance. SLC9C2 is upregulated in heart failure, with NHE11 protein levels correlating with left ventricular dysfunction and potentially representing a target for sodium/glucose cotransporter 2 inhibitor (SGLT2i) therapy 3. Additionally, SLC9C2 has been identified as a candidate gene in periodontitis-metabolic syndrome associations, with elevated expression observed in hypertensive patients 4, and as a potential prognostic biomarker in acute myeloid leukemia 5. Given its testis-specific expression pattern, SLC9C2 may represent an attractive male contraceptive target if proven essential for male fertility 2.