ARPKD (Autosomal Recessive Polycystic Kidney Disease)

Key points

• Autosomal recessive polycystic kidney disease (ARPKD) is much less common than ADPKD and is usually caused by biallelic pathogenic variants in PKHD1 on chromosome 6, encoding fibrocystin/polyductin.
• ARPKD is much less common than ADPKD ; severity ranges from lethal neonatal pulmonary hypoplasia to childhood/adult presentations.
• PKHD1 is the principal gene implicated in typical ARPKD.
• Fibrocystin/polyductin is involved in renal and biliary tubular/cystic development.
• MRCP discriminator: enlarged echogenic kidneys + childhood/neonatal renal disease + congenital hepatic fibrosis/portal hypertension → ARPKD.
• MRCP discriminator: neonatal/childhood renal disease + enlarged echogenic kidneys + congenital hepatic fibrosis/portal hypertension → ARPKD.
• Inheritance trap: ARPKD = autosomal recessive; ADPKD = autosomal dominant.