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Kidney Week

Abstract: SA-PO490

Defining the Prevalence and Clinical Characteristics of Atypical Polycystic Kidney Disease (PKD)

Session Information

  • ADPKD: Clinical Studies
    October 27, 2018 | Location: Exhibit Hall, San Diego Convention Center
    Abstract Time: 10:00 AM - 12:00 PM

Category: Genetic Diseases of the Kidney

  • 1001 Genetic Diseases of the Kidney: Cystic

Authors

  • Iliuta, Ioan-Andrei, University Health Network, Toronto, Toronto, Ontario, Canada
  • Win, Aung Zaw, University Health Network, Toronto, Toronto, Ontario, Canada
  • Shi, Beili, University Health Network, Toronto, Toronto, Ontario, Canada
  • Pourafkari, Marina, University Health Network, Toronto, Toronto, Ontario, Canada
  • Guiard, Elsa, University Health Network, Toronto, Toronto, Ontario, Canada
  • Khalili, Korosh, University Health Network, Toronto, Toronto, Ontario, Canada
  • Pei, York P., University Health Network, Toronto, Toronto, Ontario, Canada
Background

The Mayo Clinic Imaging Classification is now widely used for risk assessment of autosomal dominant polycystic kidney disease, but requires exclusion of cases with atypical kidney imaging. Here, we report the first systematic study to define the prevalence and clinical correlates of atypical PKD.

Methods

We reviewed all patients seen at the Toronto General Hospital PKD Clinic between 5/2007 to 10/2017 for their clinical, genetic, and MRI/CT results. Atypical PKD was classified as: (i) unilateral, (ii) segmental, (iii) asymmetric, (iv) lopsided, (v) mild lopsided, (vi) unilateral or bilateral atrophy, or (vii) segmental sparing.

Results

7.6% (n=36) of 472 patients reviewed displayed imaging patterns consistent with atypical PKD. Compared to patients with a typical imaging pattern, they were older with normal renal function and displayed a high rate of no mutation detected (see Table).

Conclusion

Atypical PKD is generally associated with mild kidney disease and needs to be vigorously excluded from kidney volume-based risk assessment. The etiologies of these cases are likely heterogeneous, but many may be underpinned by somatic mosaicism which can be unravelled by Next Generation Sequencing.

Characteristics of cohort
 Total (n=472)Typical (n=436)Atypical (n=36)
Age, mean [range]43 [16-78]43 [16-78]54 [20-74]
Male:Female213:259191:24522:14
Positive family history, n (%)331 (70.1)320 (73.4)11 (30.6)
Mutation class, n (%)   
PKD1 PT167 (35.4)165 (37.8)2 (5.6)
PKD1 in-frame indel16 (3.4)16 (3.7)0 (0)
PKD1 NT100 (21.2)*98 (22.5)2 (5.6)
PKD2122 (25.8)*117 (26.8)5 (13.9)
NMD68 (14.4)41 (9.4)27 (75.0)
sCreat at last follow-up, median (IQR), umol/L89 (70-122)89 (71-126)81 (70-103)
eGFR at last follow-up, median (IQR), mL/min80 (51-101)79 (49-102)82 (69-99)
TKV, median (IQR), mL1139 (625-2002)1151 (609-2101)1088 (763-1362)

*one patient had bilineal (PKD1 NT/PKD2) inheritance; PT: protein-truncating; NT: non-truncating; NMD: no mutation detected; IQR: interquartile range