[Familial hematuric nephropathies].

Alport syndrome is a hereditary hematuric nephritis progressing to end-stage renal failure, often associated with hearing loss and specific ocular changes. It is characterized by the presence of thickening and splitting of the glomerular basement membrane. Defects in type IV collagen, the main component of basement membranes, are responsible for the disease. The prevalence rate of Alport syndrome is 1/5,000 and it is the cause of about 2% of end-stage renal failure. The disease is heterogenous both at the clinical and genetic level. In most kindreds, it is transmitted as an X-linked dominant trait: males are severely affected whereas most females have a benign disease. The genes coding the different chains of type IV collagen have been cloned and several mutations have been characterized. Since prenatal counselling is now possible, the recognition of this severe familial under-diagnosed disease is of the upmost importance.