Genetic disorder frequently producing renal failure in
childhood. It is the most common genetically determined childhood cystic
disease of the kidneys. Congenital malformation of the collecting tubules.
A polycystic kidney disease classification has been
described by E.L. Potter in 1964 (see Table P-1).
P-1 Potter's Classification of Polycystic Kidney Disease ||Download (.pdf)
P-1 Potter's Classification of Polycystic Kidney Disease
|Type I||Recessive Polycystic Kidney Disease (RPKD)||Autosomal recessive pattern||Pulmonary hypoplasia; oligohydramnios; kidneys are affected bilaterally; cysts 1-2 mm on average; congenital hepatic fibrosis on autopsy|
|Type II||Multicystic Renal Dysplasia||Sporadic||Most common form of inherited cystic disease; the
cysts are variable sizes (1 mm to 1 cm), filled with clear fluid; no recognizable glomeruli and tubules. The hallmark
is the presence of “primitive ducts” in pathology (associated with Meckel-Gruber syndrome)|
|Type IIa||Large Multicystic Renal Dysplasia||Sporadic||Affected kidney is large |
|Type IIb||Small Multicystic
Renal Dysplasia||Sporadic||Hypodysplasia kidney or “quite small.” |
|Type III||Dominant Polycystic Kidney Disease (DPKD)||Autosomal dominant||Middle-aged to
older adults; progressive renal failure as the cysts become larger; rarely seen prenatally or in children; patients
are prone to have berry aneurysms of the cerebral arteries|
|Type IV||Cystic Change with Obstruction (Hallmark: cortical microcysts)||No genetic involvement
||In the fetus and newborn with urinary tract obstruction; in addition to hydroureter, hydronephrosis,
and bladder dilation; urethral valves (males) or atresia (females); oligohydramnios, pulmonary hypoplasia |
|Type V||Miscellaneous Cystic Renal Changes in Adults||No genetic involvement||The most
common cystic change of all is the appearance of one or more “simple renal cysts” in adults; may reach 10 cm or
more; present renal failure leading to long-term dialysis |
1:10,000 to 1:40,000 live births. The age distribution
of cases has two peaks, one at birth and one between the ages of 30 and 60
Autosomal recessive PKD is a neonatal disease that has
been associated to a gene map locus at 6p21.1-p12. The later form is believed to be a
familial pattern of an autosomal dominant inheritance. Both sexes are affected. There
is also a form of renal cystic disease not inherited and described as the acquired cystic kidney
disease, which develops in those individuals with long-term kidney problems.
There is distention of the renal collecting
tubules caused by localized proliferation and aberrant secretion of
epithelial cells. The expanding structures develop into cysts that are
filled with fluid containing biologically active ligands for the epidermal
growth factor receptor (EGFR), such as epidermal growth factor and
transforming growth factor-alpha. The EGFR, normally localized at the
basolateral surfaces of the collecting tubule epithelium, becomes
mislocalized to the apical surface on the cells lining cystic structures.
This mislocalization of EGFR is a common end point associated with several
different forms of PKD that are ...