Autosomal dominant PKD is the most common hereditary renal disease in the United States and affects more than 500,000 people.
The clinical disorder can be caused by at least three different genes. The most common type, ADPKDI, is carried on the short arm of chromosome 16, and the ADPKD2 gene is carried on chromosome 4. The location of the gene has not yet been determined. Clinical manifestations of ADPKD rarely fore the age of 20 to 25 years.
Therefore, many affected people of childbearing age pass the genetic trait on to offspring while they are still asymptomatic and thus unaware that they have the disease. Patients usually abdominal flank pain and back pain along with hematuria are the most common clinical manifestations. Nonspecific, dull lumbar pain frequent symptom usually occurs when the kidneys are sufficiently enlarged to be palpable examination of the abdomen. localized pain may result from cyst rupture or infection passage of a renal calculus. Microhematuria is frequently the initial sign of PKD; gross hematuria may also occur. Hypertension, the most common cardiovascular manifestation of ADPKD, occurs in about 60% of patients before the onset of renal insufficiency. Nocturia resulting from a urinary concentrating defect is often present at the time of diagnosis, and most patients show im paired salt conservation on restricted salt intake. Urinary tract infection and pyelonephritis are common complications. Up to one third of patients with PKD have multiple, asymptomatic hepatic cysts;
about 10% of patients have cerebral aneurysms; and about 25% of patients have mitral valve prolapse. Diverticulosis has also been commonly associated with ADPKD impairment. The natural history of renal functional with ADPKD is variable. The disease progresses to ESRF almost 50% of patients by age 60.
Some of the conditions associated with poor prognosis in include presence of the ADPKDI gene, male sex, black race, hypertension, clinical presentation at an earlier age, and episodes of gross hematuria. The diagnosis of PKD is made on the basis of radiographic evidence of multiple throughout the renal parenchyma, association with renal enlargement, increased elongation cortical thickness, and elongation and splaying of the renal calyces.