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Abstract: PO1280

Congenital Solitary Kidney in ADPKD: A Genotype-Phenotype Correlation

Session Information

Category: Genetic Diseases of the Kidneys

  • 1001 Genetic Diseases of the Kidneys: Cystic

Authors

  • Bucci, Romina, IRCCS Ospedale San Raffaele, Milano, Lombardia, Italy
  • Vespa, Marta, IRCCS Ospedale San Raffaele, Milano, Lombardia, Italy
  • Sciarrone Alibrandi, Maria Teresa, IRCCS Ospedale San Raffaele, Milano, Lombardia, Italy
  • Joli, Giancarlo, IRCCS Ospedale San Raffaele, Milano, Lombardia, Italy
  • Mancassola, Giulia, IRCCS Ospedale San Raffaele, Milano, Lombardia, Italy
  • Vezzoli, Giuseppe, IRCCS Ospedale San Raffaele, Milano, Lombardia, Italy
  • Manunta, Paolo, IRCCS Ospedale San Raffaele, Milano, Lombardia, Italy
Introduction

There are a very few cases of ADPKD associated with Unilateral Renal Agenesis (URA). The total amount is currently 9 cases known in the world and their renal function outcome is somewhat undefined.

Case Description

ZG is a pleasant 41-year-old man with a congenital solitary left kidney with multiple cysts and a genetic diagnosis of ADPKD. Familiarity is negative for ADPKD, but positive for URA (present in his sister and her son). Except for hypertension, there are no extrarenal ADPKD manifestations. Poster et al. analyzed 3 patients with a similar phenotype in a cohort of 182 ADPKD subjects, comparing how the volume of the single kidney increased (SKV) over time and how the GFR dropped, stratifying them for sex and age. A greater SKV in time has been recorded in these 3 patients, caused by both compensatory hypertrophy and cyst growth. Surprisingly though, their kidney function was better compared to controls. Late onset kidney failure is probably caused by hyperfiltration, and it is linked with a long-term worse outcome. In our case, ZG’s SKV increased less compared to another subject with same age and sex and with controls found in literature. Same goes for kidney function, which was better and more stable in a 10-year time-lapse compared to controls.

Discussion

The reason for this could be found in the PKD1 mutation: ZG has a missense mutation, while the aforementioned 3 cases had truncating ones. ZG’s increased SKV is probably more related to hypertrophy than cyst growth itself. Therefore, even in an unorthodox situation like this one, long-term outcome seems to depend on the genotype of the subject.

 Patient ZG
(male, 41 y/o)
Matched 2-kidney ADPKD groups
(males, y/o 34.3 to 41.4)
Patient with polycystic solitary kidney
(male, 38 y/o)
SKV (cm3) baseline490546(431-691)780
Annual SKV progression (%)26.7 (3.9-9.5)10.2
CCr
(ml/min/1.73 m2)
11491 (85-98)77

Note: Table shows values of SKV for patient ZG and patient with polycystic solitary kidney. For the matched 2-kidney ADPKD group is reported the SKV mean values with 95% CI. For this last group the volume given is that of the left kidney present in the other 2 cases. SKV is calculated from RMN scans. Creatinine clearance is estimated according to the Cockcroft-Gault formula. In the 2-kidney ADPKD group CCr is estimated by calculating both kidneys.