Persistent microscopic haematuria: Is it a benign condition? Rachel Lennon Senior Lecturer and Consultant in Paediatric Nephrology Paediatric Nephrology Study Day 12th June 2015

Overview • Differential diagnosis • Familial haematuria • Alport syndrome – Wide phenotypic variation

• Thin basement membrane nephropathy • Prognosis • Recommendations

Differential Diagnosis • Glomerular – IgA disease (HSP) – Glomerulonephritis: C3 deposition – Basement membrane glomerulopathy

• Non-glomerular – Infection, hypercalciuria, renal stone disease, polycystic kidneys, tumours, arteriovenous malformation, loin-pain-haematuria syndrome, fabricated/induced illness

Endothelial cells Matrix

Podocyte

1 million glomeruli in each human kidney…..

A specialised capillary wall

Lennon R, Randles MJ, Humphries MJ: The Importance of Podocyte Adhesion for a Healthy Glomerulus. Frontiers 2014

Barrier breakdown

Lennon R, Randles MJ, Humphries MJ: The Importance of Podocyte Adhesion for a Healthy Glomerulus. Frontiers 2014

Red cell traversing the barrier

Collar JE, Ladva S, Cairns T and Cattell V: Red cell traverse through thin glomerular basement membranes Kidney International 2001

Glomerulosclerosis

Normal

Intervention

Irreversible scarring

Familial haematuria- genetics • Alport Syndrome – COL4A3,4,5,6

• Thin basement membrane nephropathy – COL4A3,4

• Epstein/Fechtner/Sebastian/May-Hegglin – Macrothrombocytopenia – MYH9

• Glomerulopathy with fibronectin deposits – FN1

• C3/CFHR5 glomerulonephritis – CFHR5

Overview • Differential diagnosis • Familial haematuria • Alport syndrome – Wide phenotypic variation

• Thin basement membrane nephropathy • Prognosis • Recommendations

Alport Syndrome • ‘Hereditary nephritis’, hearing loss, lenticonus – Cecil Alport 1927

• Rare: 0.2/10,000, 1-3% of patients on dialysis • Molecular basis – Karl Tryggvason 1990

• Mutations – COL4A3,A4- autosomal recessive – COL4A5- X-linked

• Impaired collagen IV assembly – kidney, inner ear and eye

• ESRD: 2nd decade • Collagen network required to maintain long term GBM integrity

Electron micrograph Irregular GBM Basket weave Lamellation

Collagen IV

Collagen IV: alpha 1,1,2 Collagen IV: alpha 3,4,5: Alport syndrome Collagen IV: alpha 5,5,6

Case 1 • • • • • •

2 year old male Pyrexia, ‘cola’ coloured urine Normal creatinine and immunology Familial renal disease Microscopic haematuria and proteinuria Renal biopsy EM: – Variable thickness GBM

• Eye examination and audiometry normal • 2 mutations in COL4A5 (exons 33,35)

Case 1: Electron microscopy

Basement membrane abnormalities

Case 2 • • • • •

8 year old female with ESRD No renal biopsy Dialysis and deceased donor transplant aged 9 Satisfactory graft function at age 17 2 mutations in COL4A5 (exons 33,35) – Heterozygous

• Eye examination and audiometry normal • Skewed X-inactivation

Case 3 • 5 year old male – – – – –

Fever, elevated creatinine Persistent microscopic haematuria and proteinuria No biopsy-family history 2 mutations in COL4A5 (exons 33,35) Commenced ACE inhibition

• Renin-angiotensin blockade may slow progression of renal disease in XLAS males • Savige J, Gregory M, Gross O, Kashtan C, Ding J, Flinter F. Expert guidelines for the management of Alport syndrome and thin basement membrane nephropathy. J Am Soc Nephrol 2013;24(3):364-75.

Case 4 • • • • • •

6 month old male Facial swelling, macroscopic haematuria Nephrotic syndrome Daily 20% albumin replacement 28 day trial of steroids Renal biopsy – GBM and podocyte abnormalities

• ACE inhibition • Commenced peritoneal dialysis aged 3 • 2 mutations in COL4A5 (exons 33,35)

Case 4: Electron microscopy

Basement membrane abnormalities and podocyte foot process effacement

Other family members • Mother investigated aged 39 (affected children) – – – – –

Microscopic haematuria, mild proteinuria Normotensive eGFR 82 ml/min/1.73 m2 Started ACE inhibition Mutant COL4A5 allele

• 2 uncles (maternal) – In Pakistan – Died in 20’s ERSD

• Grandmother (maternal) ESRD age 58 – received dialysis

• Grandfather (paternal ) ESRD

Could there be an additional genetic explanation?

Genetic testing for steroid resistant nephrotic syndrome Bristol 39 genes £600 4-6 weeks

Whole exome sequencing

MYO1E • MYO1E – Encodes myosin 1E – A podocyte-expressed non-muscle myosin – Actin-rich adhesion structures modulating ECM degradation and invasion

• Case 2 and case 4 – biallelic variants in MYO1E

• MYO1E mutations – a subset of children with FSGS and glucocorticoid resistant proteinuria • Mele et.al., MYO1E mutations and childhood familial focal segmental glomerulosclerosis. N Engl J Med 2011;365(4):295-306.

Family History

Common pathways

Lennon R, Stuart HM, Bierzynska A, Randles MJ, Kerr B, Hillman KA, Batra G, Campbell J, Storey H, Flinter FA, Koziell A, Welsh GI, Saleem MA, Webb NJ, Woolf AS: Coinheritance of COL4A5 and MYO1E mutations accentuate the severity of kidney disease. Ped Nephrol 2015

Overview • Differential diagnosis • Familial haematuria • Alport syndrome – Wide phenotypic variation

• Thin basement membrane nephropathy • Prognosis • Recommendations

Benign familial heamaturia -Thin basement membrane nephropathy • 1% of the population • 30% lifetime risk of renal failure • Predisposition – 35– 50% IgAN have GBM abnormalities – 40– 50% TBMN have COL4A3/A4 mutations – Nephrotic syndrome mutation (NPHS2)

Lifetime risk of renal failure

Kaplan–Meier analysis of renal survival by age in 228 thin basement membrane nephropathy patients (118 females)

CFHR5 nephropathy patients- gender difference. Greek-Cypriot origin

Deltas C, Pierides A, Voskarides K: Molecular genetics of familial hematuric diseases Nephrol Dialysis Trans 2013

Intervention • RAAS blockade: – ACE inhibition/Angiotensin receptor blockade • Savige J, Gregory M, Gross O, Kashtan C, Ding J, Flinter F. Expert guidelines for the management of Alport syndrome and thin basement membrane nephropathy. J Am Soc Nephrol 2013;24(3):364-75.

• Anti-mIR 21: Fibrosis. Phase 1 trial • Gene therapy • Recombinant collagen IV protein

Recommendations

Deltas C, Pierides A, Voskarides K: Molecular genetics of familial hematuric diseases Nephrol Dialysis Trans 2013

Summary • Familial glomerular MH is not benign • Genetic testing- 5 genes (more to come) – Multiple mutations can explain a variable phenotype

• Risk factors for progression: Family history, genetics • Assessment by nephrology/genetics: Renal RaDaR • Lifelong BP and urinalysis • Use of RAAS blockade with persistent proteinuria