25th European Congress Pathology August-September 2013 Lisbon

1. 25th European Congress PathologyAugust-September 2013Lisbon Slide Seminar Electron Microscopy/Nephropathology Electron microscopy in focus: native and transplanted Kidney.

2. Inherited kidney diseasesImportance of Electron Microscopy for diagnosis Fernanda Carvalho Nephrology DepartmentCurry Cabral Hospital, “CHLC”, Lisbon

3. Case presentation - 1 • 22 years old caucasian female. • Serum creatinine – 1.9 mg/dL (routine analyses). • Hypertension since 16 years old. • Hyperuricemia.

4. Case presentation - 2 • Several close relatives with CKD autosomal dominant, cysts and/or gout . • Some ofthemwere in CKD stage 5, hemodialysisortransplanted. • Renal ultrasound: • Kidneywith normal size and cortico-medullar differentiation. • Bilateral cortico/medular cysts.

5. Case presentation - 3 • Urinary sediment – irrelevant • Without : • Proteinuria • Hematuria • Earing loss

6. Case presentation - 4 ? ? I.1 I.2 II.1 II.2 HD II.3 HD II.4 III.1 III.2 KT III.5 CKD cysts III.6 III.3 III.4 HD IV.1 KT IV.2 CKD cysts IV.3 IV.5 CKD IV.4 V.1 CKD cysts Pedigree analysis Filled symbols, affected individuals; open symbols, unaffected individuals; slash, deceased; HD, hemodialysis; KT, kidney transplantation; CKD, chronic kidney disease. Arrow identifies proband.

7. Case presentation - 5 In short: • Non proteinuric inherited renal phenotype, transmitted in an autosomal dominantpattern. • Affected individuals displayed hyperuricemia/gout and/or renal cysts.

8. Case presentation - 6 Differential diagnosis • ADPKD • Medullary cystic kidney disease / Familial juvenile hyperuricemic nephropathy

9. Case presentation - 7 A kidney biopsy was performed

10. KidneyBiopsy LM: Striking features in the biopsy were: • Interstitial nephritis, thickened tubular basement membranes. • Cytoplasmatic inclusions in tubular distal cells.

11. Kidney Biopsy LM

12. Kidney Biopsy LM

13. KidneyBiopsy EM: • On EM thereisswellingofendoplasmicreticulumcisternae. • Withdiscret granular inclusionsinside.

14. Electron Microscopy

15. Electron Microscopy Normal endoplasmatic reticulum

16. Kidney Biopsy IHC

17. Kidney Biopsy IHC

18. Diagnosis • Interstitial nephritis. • Dense citoplasmatic inclusions in tubular distal cells. • On electron microscopy - swelling of ER, due to the accumulation of uromodulin. + • Hyperuricemia. • Autosomal dominant inheritance. Familial juvenile hyperuricemic nephropathy /Medullary cystic Kidney disease

19. Familial juvenile hyperuricemic nephropathy • Screening for mutations in the UMOD gene The coding region of the UMOD gene was directly sequenced and a heterozygous missensemutation was found in exon 7. The c. 1463G>A (p.Gly488Asp) allele is a novel mutation and found to co-segregate with the disease in the pedigree.

20. Familial juvenile hyperuricemic nephropathy • Uromodulin (UMOD) mutations cause autosomal dominant tubulo-interstitial nephropaties that are included in the group of cystic kidney diseases: • familial juvenile hyperuricemic nephropathy (FJHN) • medullary cystic kidney disease nephropathy (MCKD

21. Familial juvenile hyperuricemic nephropathy • This complex is clinically characterized by: • alteration of urine concentration • hyperuricemia, • tubulo-interstitial fibrosis, • cortico-medullar cysts • renal failure. • Gout and hyperuricaemia suggests FJHN • Cysts on ultra-sound favours MCKD.

22. Uromodulin associated renal diseases Uromodulin associated renal diseases • Mutant uromodulin is retained in the endoplasmic reticulum and cellular trafficking is delayed, leading to reduced uromodulin secretion into urine.

23. Uromodulin associated renal diseases Mutant Uromodulin ↓ Na+/K+/ 2 Cl- TALH (ER) Uromodulin Acumulation Tubular atrophy Interstitialfibrosis ↓ VLEC ↑ Reabs. Na+ e UA Toxicity ? + APOPTOSIS ? ↓ Fr Excr UA ↓ /ø urine Uromodulin Hypertension Hyperuricemia

24. Uromodulin associated renal diseases Uromodulin associated renal diseases • It is important that physicians consider the diagnosis of FJHN in patients with a family history of hyperuricemia, hypertension associated with renal dysfunction, even if the patient has only mild renal impairment.

25. Uromodulin associated renal diseases • Equate diagnostic: • AD familial CRD • Interstitial nephritis • Irrelevant urinary sediment • Ø Proteinuria • Early hyperuricemia • To confirm diagnosis: • Hystology: LM ; EM; IHC • Genetic tests

26. Uromodulin associated renal diseases Pathologic findings in patients with UMOD mutations: • Tubular atrophy and interstitial fibrosis. • Tubular basement membrane thickening and lamellation. • Tubular or glomerular cysts (rare). • Inclusions in the cells of TALH (appear as ER inclusions on EM). • Dense intracellular UMOD inclusions in the cells of TALH ( by IHC).

27. Uromodulin associated renal diseases In patients with a poor history, inactive urine sediment and evidence of interstitial nephropathy, it is mandatory to look at the cells of TALH and distal tubules searching for abnormal inclusions by LM and EM. Its evidence implies that UMOD imunohistochemical staining must be done to confirm the composition.