# Case Report: An atypical case of ARPKD highlights the utility and challenges of implementing genetic testing in cystic kidney disease

## TL;DR

This case report describes a rare ARPKD case with a new PKHD1 mutation, showing how genetic testing helps understand and diagnose cystic kidney disease.

## Contribution

The report identifies a novel PKHD1 variant linked to a delayed-onset ARPKD phenotype.

## Key findings

- A novel PKHD1 variant (c.2713C>A; p.Gln905Lys) was found in a patient with ARPKD.
- The variant was present in trans with a known pathogenic PKHD1 variant.
- The case suggests a possible delayed juvenile onset of ARPKD due to this variant.

## Abstract

Biallelic pathogenic variants in PKHD1 cause a highly heterogenous disease, predominantly involving the kidneys and liver. Although the correlation between genotype and phenotype remains unclear, many variants in this gene have been described.

In this study, we describe a case of suspected autosomal recessive polycystic kidney disease (ARPKD) due to a novel variant in PKHD1. The patient in this instance presented with a novel PKHD1 variant (c.2713C>A; p.Gln905Lys) in trans with a previously described pathogenic variant (c.7994T>C; p.Leu2665Pro).

The PKHD1 variant c.2713C>A; p.Gln905Lys may contribute to an ARPKD phenotype with a delayed juvenile onset.