SLC9A7 is a Golgi-localized Na+/K+/H+ antiporter that mediates electroneutral influx of sodium or potassium in exchange for protons, primarily functioning in the trans-Golgi network and post-Golgi vesicles 1. It regulates pH homeostasis in Golgi secretory compartments 2 and is crucial for proper N-linked glycosylation of exported cargo proteins 1. The protein dynamically cycles between the trans-Golgi network, endosomes, and plasma membrane 3, with calcium-calmodulin regulating its transporter activity 3. Pathogenic variants in SLC9A7 cause X-linked intellectual developmental disorder. A recurrent missense variant (p.Leu515Phe) produces gain-of-function effects, alkalinizing the TGN/post-Golgi compartments and reducing N-glycosylation maturation with abnormal glycosylation profiles detected in patient sera 1. Splice site variants have been associated with intellectual disability, developmental delay, and seizures 4. However, benign variants exist with normal phenotypes in hemizygous males, indicating incomplete penetrance or variable pathogenicity depending on the specific mutation 5. Recent genome-wide association analysis identified SLC9A7 as a novel Alzheimer's disease locus 2, suggesting pH dysregulation in secretory compartments may contribute to amyloid-β accumulation and neurodegeneration.