Edrees et al also found this mutation in the PKHD1 gene among 8 out of 18 PKD Saudi patients, suggesting that mutations in this gene may be more prevalent than that of the PKD1 and PKD2 genes among Saudi patients.10 Consideration of ARPKD as a differential diagnosis in adult PKD with a negative family history has been emphasized by the finding of biallelic PKHD1 missense variants. The gene discussed is PKD1; the disease is autosomal recessive polycystic kidney disease.