Genetic and Hereditary Kidney Disorders: Autosomal Recessive Polycystic Kidney Disease (ARPKD)

Introduction

Autosomal Recessive Polycystic Kidney Disease (ARPKD) is a rare genetic disorder that primarily affects the kidneys and liver. It is caused by mutations in the PKHD1 gene and leads to cystic dilation of renal collecting ducts, hepatic fibrosis, and progressive kidney dysfunction.

Causes and Pathophysiology

Genetic Basis: Mutations in PKHD1 gene located on chromosome 6.
Cyst Formation: Leads to impaired tubulogenesis and cystic dilation of renal collecting ducts.
Hepatic Involvement: Causes congenital hepatic fibrosis.

Clinical Manifestations

Neonatal Period: Enlarged kidneys, respiratory distress due to pulmonary hypoplasia.
Infancy and Childhood: Hypertension, renal failure, hepatobiliary disease.

Diagnosis

Ultrasound: Detects enlarged echogenic kidneys.
Genetic Testing: Confirms PKHD1 mutation.
Histopathology: Shows cystic dilation of collecting ducts.

Management and Treatment

Management is largely supportive and focuses on controlling complications:

Blood pressure management with antihypertensives.
Renal replacement therapy in end-stage disease.
Management of hepatic complications such as portal hypertension.

Prognosis

The prognosis varies based on severity, with neonatal cases often having a poor outcome, while milder cases may survive into adulthood with careful management.