Glomerulocystic kidney disease in a young adult

Glomerulocystic disease

Glomerulocystic disease is a rare cause of cystic kidney diseases and can occur at any age. It is characterized by cystic dilatation of the Bowman’s capsule and normal tubules, and needs to be differentiated from other cystic renal diseases. It commonly presents as renal failure. We present a case of a 52-year-old female, with renal failure who was subsequently found to have glomerulocystic disease on renal biopsy.

Glomerulocystic kidney: one hundred-year perspective

CONTEXT

Glomerular cysts, defined as Bowman space dilatation greater than 2 to 3 times normal size, are found in disorders of diverse etiology and with a spectrum of clinical manifestations. The term glomerulocystic kidney (GCK) refers to a kidney with greater than 5% cystic glomeruli. Although usually a disease of the young, GCK also occurs in adults.

OBJECTIVE

To assess the recent molecular genetics of GCK, review our files, revisit the literature, and perform in silico experiments.

DATA SOURCES

We retrieved 20 cases from our files and identified more than 230 cases published in the literature under several designations.

CONCLUSIONS

Although GCK is at least in part a variant of autosomal dominant or recessive polycystic kidney disease (PKD), linkage analysis has excluded PKD-associated gene mutations in many cases of GCK. A subtype of familial GCK, presenting with cystic kidneys, hyperuricemia, and isosthenuria is due to uromodullin mutations. In addition, the familial hypoplastic variant of GCK that is associated with diabetes is caused by mutations in TCF2, the gene encoding hepatocyte nuclear factor-1beta. The term GCK disease (GCKD) should be reserved for the latter molecularly recognized/inherited subtypes of GCK (not to include PKD). Review of our cases, the literature, and our in silico analysis of the overlapping genetic entities integrates established molecular-genetic functions into a proposed model of glomerulocystogenesis; a classification scheme emerged that (1) emphasizes the clinical significance of glomerular cysts, (2) provides a pertinent differential diagnosis, and (3) suggests screening for probable mutations.

Glomerulocystic kidney disease and its rare associations: an autopsy report of two unrelated cases

Background

Glomerulocystic kidney disease is an uncommon type of cystic renal disease. It is characterized by cortical microsysts, which are represented by cystic dilatation of Bowman's spaces.

Case presentation

We describe a case of glomerulocystic disease in a neonate and another in an abortus associated with tracheo-oesophageal fistula and megacystic-megaureter syndrome. The kidney on autopsy was sponge-like and revealed presence of cysts corresponding to dilatations of Bowman's space microscopically. In these two cases, the Glomerulocystic Kidney Disease in one case corresponded to a sporadic form and, in the other, to a syndromic, non-heritable form of glomerulocystic kidney disease.

Conclusion

The associated anomalies in Glomerulocystic Kidney disease are well described in the literature. Two more new unrelated associations are described in this article.

Glomerulocystic kidney in a domestic dog

Glomerulocystic kidney was diagnosed in a 5-year-old female Shiba dog, which died from chronic renal failure with convulsions, vomiting and diarrhoea. Haematological examination revealed non-regenerating anaemia, azotaemia and high serum creatinine. Grossly, both kidneys were mildly atrophic with multiple small cysts in the cortex. Histopathological examination revealed marked dilatation of Bowman's space, often with glomerular atrophy or loss, and mild interstitial fibrosis. Bowman's basement membranes (BMs) were tortuous and thickened, with patchy calcification. Glomerulo-tubular junctions in the urinary pole side of the kidneys had a stenotic appearance associated with thickening of Bowman's BMs and calcification. Focal interstitial fibrosis around the glomerulo-tubular junction was also found. Continuity with the proximal tubule was evident in cystic glomeruli. Ultrastructurally, marked thickening of Bowman's BMs with many granular deposits in the urinary pole side was observed. The findings indicate that glomerular cystic changes may have developed as a consequence of glomerulo-tubular junctional stenosis due to thickened Bowman's BMs and focal periglomerular fibrosis in the urinary pole side of the kidneys.

Digital glomerular reconstruction in a patient with a sporadic adult form of glomerulocystic kidney disease

This study describes a sporadic adult form of glomerulocystic kidney disease in a 52-year-old man. To determine whether the aperture of the proximal tubule was stenosed or obstructed to clarify the pathogenesis of glomerular cyst development, 100 serial sections of the open biopsy specimen were made. Ten glomerular cysts were reconstructed using three-dimensional imaging analysis. Bowman's capsule (glomerular cyst) volume, the volume of glomerular tufts, and the area of the proximal tubular opening were estimated using imaging analysis. The volumes of Bowman's capsule and of glomerular tufts were 0.0098 +/- 0.0039 mm3 (mean +/- SD) (normal: 0.0041 to 0.0083 mm3) and 0.0026 +/- 0.0013 mm3, respectively. The area of the proximal tubular opening was 0.0017 +/- 0.0003 mm2 (normal: 0.0012 to 0.0028 mm2). There was neither obstruction nor stenosis of the opening of the renal tubule in this sporadic adult form of glomerulocystic kidney disease. After 4 years of hemodialysis, the glomerular cysts, as well as the kidneys, enlarged. This study shows that the main cause of glomerular cyst development is not glomerulotubular neck obstruction.