Case Report: Early-onset portal hypertension revealing pediatric ADPKD with a truncating PKD1 variant.

Background: Autosomal dominant polycystic kidney disease (ADPKD) is a multisystemic ciliopathy whose clinical spectrum extends into childhood. Although hepatic cysts are the most common extrarenal manifestation, early portal hypertension associated with congenital hepatic fibrosis (CHF)-like features is uncommon and likely underrecognized. Case presentation: We report a 10-year-old girl with no known family history of ADPKD who presented at 9 years of age with upper gastrointestinal bleeding secondary to grade III esophageal varices. The diagnostic evaluation established non-cirrhotic portal hypertension, and she underwent endoscopic variceal ligation followed by secondary prophylaxis with propranolol. Imaging demonstrated hepatosplenomegaly, patent portal and splenic veins, and no hepatic cysts. Liver biopsy showed mild portal fibrosis (METAVIR F1), while liver stiffness measured 6.4 kPa, consistent with mild fibrosis. Renal imaging revealed multiple bilateral cortical cysts, and whole-exome sequencing identified a heterozygous truncating PKD1 variant (p.Glu1633Ter), classified as pathogenic according to ACMG criteria. The patient remains clinically stable without recurrent bleeding during multidisciplinary follow-up. Discussion: This case expands the phenotypic spectrum of pediatric ADPKD by illustrating clinically significant portal hypertension despite only mild hepatic fibrosis. It also highlights the importance of integrating histopathology, non-invasive liver assessment, imaging, and molecular testing when evaluating children with unexplained non-cirrhotic portal hypertension. Conclusion: ADPKD should be considered in the differential diagnosis of pediatric non-cirrhotic portal hypertension, even in the absence of hepatic cysts. Early genetic testing may facilitate accurate diagnosis and appropriate multidisciplinary management.