Alport syndrome is a genetic and hereditary disease, caused by mutations in the type IV collagen genes COL4A3, COL4A4 and COL4A5, that affects the glomerular basement membrane of the kidney. It is a rare disease with an underestimated prevalence. Genetic analysis of population cohorts has revealed that it is the second most common inherited kidney disease after polycystic kidney disease. Renal involvement is the main manifestation, although it may have associated extrarenal manifestations such as hearing loss or ocular problems. The degree of expression of the disease changes according to the gene affected and other factors, known or yet to be known. The pathophysiology is not yet fully understood, although some receptors, pathways or molecules are known to be linked to the disease. There is also no specific treatment for Alport syndrome; the most commonly used are renin–angiotensin–aldosterone system inhibitors. In recent years, diagnosis has come a long way, thanks to advances in DNA sequencing technologies such as next-generation sequencing (NGS). Further research at the genetic and molecular levels in the future will complete the partial vision of the pathophysiological mechanism that we have, and will allow us to better understand what is happening and how to solve it.
Hereditary renal tubulopathies are rare monogenic disorders caused by defects in tubular transport mechanisms that impair the handling of electrolytes, water, and acid–base balance along the nephron. While each tubulopathy is individually uncommon, their collective burden is clinically relevant, as these disorders can severely affect quality of life and predispose to nephrolithiasis, dehydration episodes, and progression to chronic kidney disease. Advances in molecular genetics have identified more than 70 genes involved in renal tubular physiology; however, a substantial proportion of these cases remain genetically unresolved, and marked phenotypic heterogeneity complicates diagnosis and management. This narrative review provides an integrated overview of the main transport systems operating in the different tubular segments of the nephron—proximal tubule, thick ascending limb of the loop of Henle, distal convoluted tubule and collecting duct—summarizing the tubulopathies associated with each segment and discussing in greater detail representative inherited disorders that illustrate the clinical consequences of their dysfunction. We highlight current diagnostic challenges and limitations of existing therapeutic strategies and discuss novel diagnostic approaches as well as emerging treatment options. Improved genetic diagnosis, validation of candidate biomarkers, and the development of novel therapeutic strategies will be essential to advance precision medicine and improve outcomes for patients with inherited renal tubulopathies.