Genetics

A possible genetic association between Fabry disease and renal ectopia—two rare conditions that have not previously been reported together—has been identified. Rákóczi and colleagues found an identical mutation in the α-galactosidase A gene in three family members who had Fabry disease and renal ectopia. A haplotype located close to this gene cosegregated with renal ectopia, and showed an X-linked dominant pattern of inheritance.

Rákóczi, É. et al. Association of renal ectopia with Fabry's disease in 3 patients. J. Urol. 181, 1949–1954 (2009).

Pathology

Absence of mesangial C4d staining on renal biopsy samples could be a useful prognostic marker for identifying patients with IgA nephropathy who have a good long-term prognosis and do not require aggressive treatment. Espinosa and colleagues found that 10-year renal survival was markedly lower in 19 patients with glomerular C4d staining than in 40 patients without C4d staining (43.9% versus 90.9%).

Espinosa, M. et al. Mesangial C4d deposition: a new prognostic factor in IgA nephropathy. Nephrol. Dial. Transplant. 24, 886–891 (2009).

Mineral metabolism

Chewing gum containing a salivary phosphate-binding polymer might be a practical addition to the treatment of hyperphosphatemia in patients on dialysis, say researchers in Italy. Salivary and blood phosphate levels decreased significantly in 13 hyperphosphatemic hemodialysis patients who chewed phosphate-binding gum twice daily between meals and continued taking their traditional phosphate binders during meals for 2 weeks.

Savica, V. et al. Salivary phosphate-binding chewing gum reduces hyperphosphatemia in dialysis patients. J. Am. Soc. Nephrol. 20, 639–644 (2009).

Chronic kidney disease

Amitriptyline, a tricyclic antidepressant, might be effective for the treatment of chronic kidney disease. Achar and colleagues at the Federal and City Universities of São Paulo, Brazil, found that amitriptyline treatment reduced interstitial fibrosis and inflammation and downregulated several markers of progressive tubulointerstitial injury in a mouse model of unilateral ureteral obstruction.

Achar, E. et al. Amitriptyline attenuates interstitial inflammation and ameliorates the progression of renal fibrosis. Kidney Int. 75, 596–604 (2009).