Strong Genetic

Autosomal Recessive Polycystic Kidney Disease (ARPKD)

Name: Autosomal Recessive Polycystic Kidney Disease (ARPKD)
Creator: Realised
Published: 2026-03-01

GenePKHD1rsIDrs137852944, rs137852945, rs137852946InheritanceAutosomal recessiveCarrier frequency~1 in 70 general populationSystemCarrier Screening

Summary

ARPKD is a condition where both kidneys develop fluid-filled cysts in the collecting ducts, combined with progressive fibrosis of the liver (congenital hepatic fibrosis). The PKHD1 gene encodes fibrocystin, a protein involved in the normal development of kidney tubules and bile ducts. It is important to distinguish ARPKD from the much more common autosomal dominant PKD (ADPKD), which is a different gene, different mechanism, and typically presents in adulthood.

Practical takeaway

This matters when planning children. With a general population carrier frequency of approximately 1 in 70, partner carrier testing is a reasonable consideration. A carrier test through a GP or genetic counselling service can determine your partner's status. If you are both carriers, a genetic counsellor can discuss the range of severity, prenatal detection options (enlarged kidneys can often be seen on prenatal ultrasound), and the current treatment landscape. The reassurance: milder presentations are common, and even severe cases have improving outcomes with modern neonatal and nephrology care. Realised does not calculate reproductive risk or advise on reproductive decisions.

Evidence detail

What Carrier Status Means For You

You are not affected. One working copy of PKHD1 produces sufficient fibrocystin for normal kidney and liver development. Your kidneys and liver function normally. Your carrier status becomes relevant if your partner also carries a PKHD1 variant. In that case, each child has a 25% chance of having ARPKD, a 50% chance of being an unaffected carrier, and a 25% chance of inheriting neither variant.

Population Context

ARPKD occurs across all ethnic groups with a roughly similar incidence of 1 in 20,000-40,000 live births. Carrier frequency is approximately 1 in 70 in the general population. Unlike many other recessive conditions, ARPKD does not show dramatic population-specific frequency differences, though some variants are more common in certain populations. The PKHD1 gene is one of the largest human genes (67 exons spanning ~470 kb of genomic DNA), which partly explains the extreme genetic heterogeneity — most affected individuals are compound heterozygotes carrying two different variants.

Limitations

23andMe tests 3 of over 750 known pathogenic PKHD1 variants. Due to the extreme genetic heterogeneity of PKHD1 (most families have private or rare variants), consumer testing captures only a small fraction of carrier risk. A "not detected" result provides only modest reduction in carrier risk. Comprehensive carrier screening through a clinical laboratory, including sequencing and deletion/duplication analysis of the full gene, is recommended if a partner is a known carrier or there is family history of ARPKD. Prenatal ultrasound can detect severely affected pregnancies but may miss milder cases.

Sources (5)

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