Renal Dysplasia in the Grey Alpine breed unrelated to CLDN16 mutations

RENAL dysplasia (RD) is a developmental disorder of the renal parenchyma characterised by anomalous differentiation of the nephrons and collecting ducts (Woolf and others 2004). In human medicine, RD is one of the principal causes of childhood end-stage renal failure. In veterinary medicine, it has been described in several species, including cattle (Dunham and others 1989, Simon and others 1999, Ohba and others 2001, Castro and others 2007, Maxie and Newman 2007, Aresu and others 2009, Philbey and others 2009). In Japanese Black cattle, RD shows autosomal recessive inheritance, caused by CLDN16 mutations (Hirano and others 2000, Ohba and others 2000, Hirano and others 2002). These mutations affect one of the members of the claudin family of genes which plays an important role in the formation of tight junctions in the kidney (Simon and others 1999). In Japanese Black cattle, RD is classified into two types, according to two independent CLDN16 mutations (Hirano and others 2002), but no morphological or histopathological differences between the two types have been reported. This short communication deals with a case of RD in twin grey Alpine heifers which are not related to mutations of the CLDN16 gene