Clinical case of fibronectin glomerulopathy

Abstract

Fibronectin glomerulopathy (FNGP) is an extremely rare glomerulopathy with an autosomal dominant pattern of inheritance. Sporadic cases of the disease are also described. Currently, several types of FN1 gene mutations are known that underlie conformational changes in the fibronectin molecule and lead to its deposition in the renal tissue. The clinical manifestations of FNGP may be very heterogeneous, but in most cases are characterized by proteinuria, microscopic hematuria, arterial hypertension, and long-term progressive renal failure. Renal biopsy is the main method for diagnosing the disease. Histologically, GFND is characterized by a lobular glomerular architecture with mesangial expansion and obliteration of capillary loops due to the accumulation of an acellular, periodic acid–Schiff positive, silver Jones-negative material. Immunofluorescence is usually negative. Electron microscopy shows finely granular or fibrillary mesangial and subendothelial electron-dense deposits. At higher magnifications, the fibrils have a diameter of 12-16 nm and are randomly arranged. Standard protocols for the etiopathogenetic therapy of FNGP are not currently developed. Improvement of clinical status and prognosis can be achieved by optimizing blood pressure and proteinuria control by renin–angiotensin–aldosterone system blockers. The recurrence risk of FNGP after renal transplantation remains uncertain due to the rare prevalence of the pathology. In this article, we report a 25-year-old man with nephrotic syndrome, which occurred after a previous upper respiratory tract infection. Histological changes specific to FNGP were found in the kidney biopsy. Genetic analysis was not performed. The absence of a family history of kidney disease suggests that this is a sporadic case of FNGP.