CFHR5 nephropathy
Encyclopedia
Complement factor H-related protein 5 (CFHR5) nephropathy (also known as Troodos nephropathy) is a form of inherited kidney disease which is endemic in Cyprus and is caused by a mutation in the gene CFHR5
. It is thought to affect up to 1:6000 Cypriots but has not been reported in anybody who is not of Cypriot descent.
regulation, rather than activation of the complement system
by other diseases. In addition, light microscopy often demonstrates histological features of mesangiocapillary glomerulonephritis. CFHR5 Nephropathy is histologically distinguished from dense deposit disease
by the absence of dense transformation of the glomerular basement membrane – electron microscopy rather reveals mesangial, subendothelial basement membrane
, and occasional subepithelial basement membrane deposits which stain for complement C3.
or kidney transplantation
. For reasons which are not understood, women with the disease, although they often have blood in their urine, only rarely develop kidney failure. The disease has been shown to recur following kidney transplantation
, however in most cases the kidney transplant has a normal lifespan.
CFHR5
Complement factor H-related protein 5 is a protein that in humans is encoded by the CFHR5 gene.-Function:CFHR5 is structurally related to complement factor H which plays an important role in the regulation of a branch of the innate immune system called the alternative complement pathway...
. It is thought to affect up to 1:6000 Cypriots but has not been reported in anybody who is not of Cypriot descent.
Clinical features
CFHR5 nephropathy usually presents with microscopic amounts of blood in the urine, detectable on a routine urine dipstick test. Sometimes the disease is associated with visible blood in the urine, usually at the time of respiratory or other infections and this is thought to result from stimulation of the immune system leading to damage in the kidneys.Biopsy findings
A kidney biopsy in patients with CFHR5 nephropathy classically shows deposition of complement C3 in the kidney, without any detectable immunoglobulins there. This is evidence that the disease is caused by a problem with alternative complement pathwayAlternative complement pathway
The alternative pathway of the complement system is an innate component of the immune system's natural defense against infections, which can operate without antibody participation....
regulation, rather than activation of the complement system
Complement system
The complement system helps or “complements” the ability of antibodies and phagocytic cells to clear pathogens from an organism. It is part of the immune system called the innate immune system that is not adaptable and does not change over the course of an individual's lifetime...
by other diseases. In addition, light microscopy often demonstrates histological features of mesangiocapillary glomerulonephritis. CFHR5 Nephropathy is histologically distinguished from dense deposit disease
Membranoproliferative glomerulonephritis
Membranoproliferative glomerulonephritis , also known as mesangiocapillary glomerulonephritis, is a type of glomerulonephritis caused by deposits in the kidney glomerular mesangium and basement membrane thickening, activating complement and damaging the glomeruli.MPGN accounts for approximately 4%...
by the absence of dense transformation of the glomerular basement membrane – electron microscopy rather reveals mesangial, subendothelial basement membrane
Glomerular basement membrane
The glomerular basement membrane is the basal laminal portion of the glomerulus. The Glomerular capillary endothelial cells, the GBM and the filtration slits between the podocytes perform the filtration function of the glomerulus, separating the blood in the capillaries from the filtrate that...
, and occasional subepithelial basement membrane deposits which stain for complement C3.
Prognosis
Over time, kidney failure can develop and most men with the disease will eventually require dialysisDialysis
In medicine, dialysis is a process for removing waste and excess water from the blood, and is primarily used to provide an artificial replacement for lost kidney function in people with renal failure...
or kidney transplantation
Kidney transplantation
Kidney transplantation or renal transplantation is the organ transplant of a kidney into a patient with end-stage renal disease. Kidney transplantation is typically classified as deceased-donor or living-donor transplantation depending on the source of the donor organ...
. For reasons which are not understood, women with the disease, although they often have blood in their urine, only rarely develop kidney failure. The disease has been shown to recur following kidney transplantation
Kidney transplantation
Kidney transplantation or renal transplantation is the organ transplant of a kidney into a patient with end-stage renal disease. Kidney transplantation is typically classified as deceased-donor or living-donor transplantation depending on the source of the donor organ...
, however in most cases the kidney transplant has a normal lifespan.