[Nail-patella syndrome without extra-renal lesions. A new hereditary glomerular nephropathy]

We observed an unusual glomerular disease in eight pediatric patients. Clinical features of this early, progressive renal disease included increased blood pressure in many cases, extrarenal hematologic and pulmonary symptoms, and, in one of our patients and two genetically related children, hemolytic uremic syndrome with thrombotic microangiopathy resulting in permanent renal failure. Histologic studies showed major and complex modifications of glomerular capillary walls and electron microscopy disclosed numerous bundles of fibrillar collagen within the extracellular glomerular matrix. Clinical and genetic investigations out-ruled hereditary osteo-onychodysplasia, a condition in which fibrillar collagen is found within glomerular basement membranes. In addition results of family studies were consistent with autosomal recessive transmission of this new entity.