Genetic and Diagnostic Distinctions between ADPKD and ARPKD

Inheritance Patterns

Genetic Basis

Age of Onset and Typical Clinical Presentation

Extrarenal Manifestations (ADPKD)

Diagnostic Imaging Criteria for ADPKD (Adults)

Role of Genetic Testing

Prognostic Indicators in ADPKD

Differential Diagnosis and Diagnostic Pitfalls

Renal Cyst Development and Associated Factors

Genetic Causes

• The American College of Medical Genetics recommends that PKD1 and PKD2 gene mutations are the primary causes of Autosomal Dominant Polycystic Kidney Disease (ADPKD), with PKD1 mutations causing more severe disease than PKD2 5
• The National Kidney Foundation states that Autosomal Recessive Polycystic Kidney Disease (ARPKD) results from mutations in PKHD1, DZIP1L, CYS1, or PKD1 genes, and Autosomal Dominant Tubulointerstitial Kidney Disease (ADTKD) is caused by mutations in UMOD, MUC1, REN, or SEC61A genes 5, 6
• The European Renal Association notes that HNF1B-related kidney disease is caused by HNF1B mutations, with up to 50% appearing as de novo cases, and Tuberous sclerosis complex is caused by TSC1 or TSC2 mutations 5, 6
• The International Society of Nephrology reports that Von Hippel-Lindau syndrome is caused by VHL gene mutations 6

Acquired Causes

• The American Society of Nephrology states that end-stage renal disease is the primary driver of Acquired Cystic Disease (ACD), occurring exclusively in this setting, and duration of hemodialysis directly correlates with increased cyst occurrence 7, 8
• The National Institute of Diabetes and Digestive and Kidney Diseases notes that male gender is associated with higher risk of developing ACD, and cysts in ACD can show proliferative changes with multilayered epithelium and harbor cytogenetic alterations 7, 8
• The Kidney Disease: Improving Global Outcomes (KDIGO) organization reports that recent genetic studies identified recurrent mutations in KMT2C and TSC2 in ACD-associated renal cell carcinoma 7, 8

Clinical Considerations

• The American Academy of Pediatrics recommends that a normal fetal or childhood ultrasound does not exclude ADPKD in at-risk children, as cysts develop gradually and may not be detectable early in milder phenotypes 9
• The European Society of Human Genetics notes that approximately 3% of children with ADPKD-causing mutations have very-early-onset or unusually rapid progressive disease, and assuming all simple-appearing cysts are truly non-proliferative is a critical error 10
• The National Kidney Foundation states that multiple inherited disorders can mimic ADPKD with kidney and/or liver cysts, including collagen disorders, nephrolithiasis-associated conditions, and syndromic ciliopathies 5, 6