[Nail-patella syndrome: clinico-pathologic characteristics]

The nail-patella syndrome is a hereditary disorder showing an autosomal dominant trait. It is characterized by a series of skeletal disorders and nephropathy. The skeletal defects and the renal involvement might occur separately. The usual clinical presenting syndromes of the nephropathy are asymptomatic proteinuria, microscopic haematuria and sometimes nephrotic syndrome. In a considerable proportion of patients renal failure develops. We summarise the clinico-pathological features of the disease presenting in two children and in a young man. The two children showed heavy microscopic occasionally, macroscopic haematuria, asymptomatic proteinuria and the adult patient had nephrotic syndrome. Nail-patella abnormalities were observed in one child without the involvement of family members. Except for the mother of the other child no urine abnormalities could be demonstrated in the patient's families. The kidney biopsy revealed the characteristic signs of the nail-patella syndrome in different extent: bundles of collagen fibrils in the glomerular basement membrane (GBM). Segmental and thinning of the GBM also occurred in the two children. This defect predisposes to the clinically dominant micro- and macroscopic haematuria. These children's reual function remained stable during the follow-up period of 4-7 years. In the GBM of the third patient small subepithelial electron dense deposits-corresponding to stage I. membranous glomerulonephritis- and extensive collagen deposition was found. After two years follow-up persistent nephrotic syndrome and gradual decline in renal function could be observed.