All of the following are true about childhood polycystic kidney disease, except
**Childhood Polycystic Kidney Disease (PKD)**
**Core Concept**
Childhood PKD, also known as autosomal recessive polycystic kidney disease (ARPKD), is a rare genetic disorder characterized by the development of multiple cysts in the kidneys, leading to renal failure and potentially other systemic manifestations. It is caused by mutations in the PKHD1 gene, which encodes a protein involved in the formation and function of the cilium, a microtubule-based structure essential for renal tubular cell function.
**Why the Correct Answer is Right**
ARPKD is typically diagnosed in infancy or early childhood, and the disease progression is rapid, often resulting in renal failure by the age of 10. The cysts in ARPKD are usually small and uniform, and the kidneys are enlarged and firm. Liver cysts and fibrosis are also common in ARPKD, and patients may experience symptoms such as abdominal distension, jaundice, and failure to thrive. The disease is inherited in an autosomal recessive pattern, meaning that both parents must be carriers to pass the disease to their offspring.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because ARPKD is not associated with a mutation in the PKD1 gene, which is responsible for autosomal dominant polycystic kidney disease (ADPKD). Instead, ARPKD is caused by mutations in the PKHD1 gene.
**Option B:** This option is incorrect because ARPKD is not typically diagnosed in adulthood. While some individuals with ARPKD may not be diagnosed until later in life, the disease is usually identified in infancy or early childhood.
**Option C:** This option is incorrect because the cysts in ARPKD are not typically large and hemorrhagic, as seen in ADPKD. Instead, the cysts in ARPKD are usually small and uniform.
**Clinical Pearl / High-Yield Fact**
A key characteristic of ARPKD is the presence of small, uniform cysts in the kidneys, which can be distinguished from the larger, more variable cysts seen in ADPKD. This distinction is important for diagnosis and management.
**Correct Answer:** A.