H+-ATPases are ubiquitous in nature; V-ATPases pump protons against an electrochemical gradient, whereas F-ATPases reverse the process, synthesizing ATP. We demonstrate here that mutations in ATP6B1, encoding the B-subunit of the apical proton pump mediating distal nephron acid secretion, cause distal renal tubular acidosis, a condition characterized by impaired renal acid secretion resulting in metabolic acidosis. Patients with ATP6B1 mutations also have sensorineural hearing loss; consistent with this finding, we demonstrate expression of ATP6B1 in cochlea and endolymphatic sac. Our data, together with the known requirement for active proton secretion to maintain proper endolymph pH, implicate ATP6B1 in endolymph pH homeostasis and in normal auditory function. ATP6B1 is the first member of the H+-ATPase gene family in which mutations are shown to cause human disease.

We believe that AHEI is a benign disorder, despite its dramatic appearance. We want to point out that mucosal and trunk involvement may also occur in AHEI.

Our results suggest that endothelial damage starts in the early stage of CKD, that the endothelial dysfunction becomes overt with the increase of cardiovascular risk factors and that EMPs may be a reliable marker of the subclinical atherosclerosis and arterial stiffness.

M694V homozygosity is associated with phenotype II and amyloidosis compared to other common genotypes in patients with FMF. Despite current knowledge on FMF, prospective clinical studies with large numbers of patients and different ethnic groups will help us to clarify this considerable disease.

FMF is the leading cause of secondary amyloidosis in Turkey, followed by tuberculosis. Oedema accompanied by proteinuria is the most prominent presenting finding, and hypotension seems to be common among these patients.