The complex array of nephronophthisis

The term nephronophthisis refers to a group of early onset renal cystic diseases with autosomal recessive inheritance. Despite its rarity, nephronophthisis is the most frequent cause of end stage renal failure of genetic origin in the first three decades of life. With the discovery in recent years of several genes responsible for this disease an unexpected molecular and clinical complexity is progressively being outlined regarding this condition. Mutations in the same gene can have as a consequence disparate clinical manifestations without any apparent explanation. Sometimes, mutations in both the alleles of one of the nine known nephronophthisis genes have been found in the same affected individual together with a mutation in one of the remaining eight genes, raising the possibility that the observed phenotype is the result of a trior poly-allelic inheritance. Mutations in the nine known genes only explain about 30% of the cases of nephronophthisis. Thus, more genes are likely to underlie this disease and their discovery will be of undoubted benefit to the comprehension of its molecular basis.