Alport syndrome is a hereditary nephropathy, inconstantly associated with sensorineural deafness and ocular abnormalities. These manifestations result from a structural defect in type IV collagen. Recent genetic advances have provided a molecular basis for the two main subsets of the disease, namely the X-linked and the autosomal recessive forms. It has just been shown that the autosomal dominant entity known as benign familial haematuria is actually due to a heterozygote mutation of the gene accounting for the autosomal recessive form of Alport syndrome. The genetic breakthrough has already clinical and pathophysiological implications.