Dense deposit disease (DDD) is a rare kidney disease that stops the kidneys from correctly filtering waste from the blood. The name is descriptive of the electron-dense changes that transform the middle layer (lamina densa) of the glomerular basement membrane (GBM) in a segmental, discontinuous or diffuse pattern. The glomeruli are the filtering units of the kidney. Blood flows through very small capillaries in each glomerulus where it is filtered through the GBM to form urine. When DDD is present, deposits in the GBM lead to disruption of kidney function. Because damage to glomeruli is progressive, about half of all persons with DDD experience kidney failure after living with their disease for 10 years. The development of kidney failure means that dialysis or transplantation must be started.
In addition to dense deposits in the GBM, persons with DDD can develop deposits in their eyes along an interface called the choriocapillaris-Bruch's membrane-retinal pigment epithelium. This region is very similar to the capillary-GBM interface in the kidney. The eye deposits are called drusen.