Dense deposit disease (DDD) is a condition that primarily affects kidney function. Signs and symptoms usually start between the ages of 5 and 15 but may also begin in adulthood. The major features of DDD are due to kidney malfunction, and often include proteinuria; hematuria; reduced amounts of urine; low levels of protein in the blood; and swelling in many areas of the body. About half of affected people develop end-stage renal disease (ESRD) within 10 years after symptoms start. DDD can have genetic or non-genetic causes. It can be caused by mutations in the C3 and CFH genes; it may develop as a result of both genetic risk factors and environmental triggers; or it can result from the presence of autoantibodies that block the activity of proteins needed for the body's immune response. Most cases are sporadic (occurring by chance in people with no history of the disorder in their family).

Some people with DDD develop a buildup of yellowish deposits called drusen in the retina of the eye. These deposits usually appear in childhood or adolescence and can cause vision problems later in life. The long-term risk of vision problems in people with DDD is about 10% (1 in 10).

DDD can sometimes be associated with other conditions that are not related to kidney function. For example, it can occur with acquired partial lipodystrophy (APL), a condition characterized by a lack of fatty tissue under the skin of the upper body. In people with APL, the loss of fat in the upper body usually occurs several years before kidney disease starts.

C3 and CFH genes, but they account for only a small percentage of all cases. There are also variants of some genes (C3, CFH and CFHR5) that do not directly cause the condition, but increase the likelihood of developing the condition. Most people with these variants do not develop the condition.

Most people with DDD do not have disease-causing mutations in the C3, CFH, or CFHR5 genes. The condition may develop due to a combination of genetic and environmental risk factors ("triggers"), most of which are unknown. The condition can also be caused by the presence of specific proteins called autoantibodies that block the activity of proteins needed for the body's immune response.

In people with DDD that are known to have disease-causing mutations in the CFH gene, the inheritance pattern is autosomal recessive. The children of a person with autosomal recessive DDD will definitely be carriers of the condition. Carriers of autosomal recessive conditions typically do not have any signs or symptoms. Genetic carrier testing for at-risk family members is possible if the two CFH mutations have been identified in the affected family member.

DDD has been seen in families in which other relatives have autoimmune disorders, such as celiac disease and type 1 diabetes mellitus.

Individuals who have questions or concerns about the risk to themselves or family members should speak with a genetics professional.

People with DDD who develop end-stage renal disease typically need peritoneal dialysis or hemodialysis. Kidney transplant may be an option for some individuals; however, DDD will still develop in virtually all transplanted kidneys and about half of transplants will ultimately fail. There is some evidence that the likelihood of transplant failure due to recurrent DDD decreases with time.