This work is a clinical and genetic analysis of the autosomal Alport syndrome and collagen IV nephropathy (alpha 3/alpha 4). It contains the description of three new pathogenic mutations which lead to autosomal dominant Alport syndrome: one in the COL4A3 gene and the other two in the COL4A4 gene. It also contains the study of the clinical course of the autosomal dominant Alport syndrome in a spanish population, which is as agressive as the one in the other paths of inheritance.