What is the least common and most fatal autosomal recessive kidney disease characterized by cysts?

Infantile polycystic kidney disease (IPKD) is an autosomal recessive disorder that typically manifests in infants or in utero, leading to severe complications and a high mortality rate. This condition is characterized by the presence of numerous cysts that predominantly affect the kidneys and liver. It occurs due to mutations in the PKHD1 gene, which plays a crucial role in kidney and biliary development.

The cysts formed in IPKD are not only more numerous but are also associated with dysplastic changes in renal architecture, leading to significant impairment of renal function early in life. This can result in various complications, including pulmonary hypoplasia due to oligohydramnios and systemic hypertension, which are common in affected infants. As a result, many infants with this condition have a reduced life expectancy, underscoring its classification as a fatal disease.

In contrast, the other conditions listed, such as adult polycystic kidney disease, acquired cystic kidney disease, and medullary sponge kidney, do not share the same severity and poor prognosis in the early years of life, and are generally not classified as the least common and most fatal autosomal recessive kidney disease characterized by cysts.