Autosomal dominant polycystic kidney disease

A genetic disorder characterized by the growth of numerous cysts in the kidneys

Adult polycystic kidney

Autosomal dominant polycystic kidney disease
Synonyms	Autosomal dominant PKD, adult-onset PKD
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Field	Nephrology, Medical genetics
Symptoms	Flank pain, hematuria, hypertension, abdominal mass, urinary tract infections, kidney stones
Complications	Chronic kidney disease, end-stage renal disease, liver cysts, intracranial aneurysm, cardiac valve abnormalities
Onset	Usually between ages 30–40
Duration	Lifelong, progressive
Types	Type 1 (PKD1 gene), Type 2 (PKD2 gene)
Causes	Mutations in PKD1 or PKD2 genes
Risks	Family history of ADPKD
Diagnosis	Ultrasound, CT scan, MRI, genetic testing
Differential diagnosis	Autosomal recessive polycystic kidney disease, simple kidney cysts, tuberous sclerosis
Prevention	None
Treatment	Blood pressure control, pain management, treatment of infections, dialysis, kidney transplant
Medication	Tolvaptan, antihypertensives, analgesics
Prognosis	Progressive; many develop end-stage kidney disease by age 60
Frequency	~1 in 400 to 1 in 1,000 live births
Deaths	Often due to renal failure or complications from hypertension

Illustration of PKD1 and PKD2 proteins at the cell membrane

Diagram of autosomal dominant polycystic disease with a normal kidney inset for comparison

Abdominal CT scan of an adult with autosomal dominant polycystic kidney disease: Extensive cyst formation is seen over both kidneys, with a few cysts in the liver, as well. (Coronal plane)

Autosomal dominant polycystic kidney disease (ADPKD) is a genetic disorder characterized by the development of numerous cysts in the kidneys. These cysts can lead to a variety of complications, including hypertension, kidney pain, and ultimately kidney failure. ADPKD is one of the most common inherited kidney disorders.

Genetics

ADPKD is caused by mutations in the PKD1 or PKD2 genes. The PKD1 gene is located on chromosome 16 and accounts for approximately 85% of cases, while the PKD2 gene is located on chromosome 4 and accounts for about 15% of cases. The disease is inherited in an autosomal dominant pattern, meaning that an affected individual has a 50% chance of passing the mutated gene to each offspring.

Pathophysiology

The pathophysiology of ADPKD involves the formation of fluid-filled cysts in the kidneys. These cysts arise from the renal tubules and progressively enlarge, leading to the distortion of normal kidney architecture. The expansion of cysts can cause compression of surrounding renal tissue, leading to decreased kidney function over time. The exact mechanism by which mutations in PKD1 and PKD2 lead to cyst formation is not fully understood, but it is believed to involve defects in cilia function and cellular signaling pathways.

Clinical Features

The clinical presentation of ADPKD can vary widely among individuals. Common symptoms include:

• Hypertension
• Flank or abdominal pain
• Hematuria (blood in urine)
• Recurrent urinary tract infections
• Kidney stones

As the disease progresses, patients may develop chronic kidney disease and eventually end-stage renal disease (ESRD), requiring dialysis or kidney transplantation.

Diagnosis

ADPKD is typically diagnosed through imaging studies such as ultrasound, CT scan, or MRI, which can reveal the presence of multiple renal cysts. Genetic testing can confirm the diagnosis by identifying mutations in the PKD1 or PKD2 genes.

Management

There is currently no cure for ADPKD, but management focuses on controlling symptoms and slowing disease progression. Treatment options include:

• Blood pressure control, often with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers
• Pain management
• Treatment of urinary tract infections
• Dietary modifications to reduce salt intake

In advanced cases, dialysis or kidney transplantation may be necessary.

Prognosis

The prognosis of ADPKD varies, with some individuals maintaining adequate kidney function for many years, while others progress to ESRD by middle age. Factors influencing prognosis include the specific genetic mutation, the rate of cyst growth, and the presence of complications such as hypertension.

Related pages

• Polycystic kidney disease
• Chronic kidney disease
• Kidney transplantation
• Hypertension

External links

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