Dent’s disease: genetics, diagnosis, treatment Larisa Prikhodina Department of Inherited & Acquired Kidney Diseases, Research Institute of Pediatrics & Children’ Surgery, Moscow, Russia The IPNA/ESPN Teaching Course “Pediatric Nephrology: evidence-based statements and open questions“ Moscow, Russia October 22-24, 2013
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Dent’s disease:genetics, diagnosis, treatment
Larisa Prikhodina
Department of Inherited & Acquired Kidney Diseases,Research Institute of Pediatrics & Children’ Surgery,
Moscow, Russia
The IPNA/ESPN Teaching Course “Pediatric Nephrology: evidence-based statements
and open questions“
Moscow, RussiaOctober 22-24, 2013
Clinical case
History:• Since age of 10 mo: proteinuria isolated without NS: 0.5-1.4-3.5 g/L• 1 and 4 y. (locally): steroids 2 mg/kg/d – no effect; Dx: SRNS• 8 y.: CsA 5 mg/kg/d + steroids 1 mg/kg/d for 10 mo – no effect, serum Cr +50%
Age on admission: 9 y.o.• Short stature: height: <5‰, weight: 25‰
Dent’s disease 1: characteristics in males Major features Definitions Affected males
with CLCN5 mutations
LMW proteinuria (M< 30 kDa)
≥5-x increasing of urinary RBP, β2- or α1 microglobulins
100%
Hematuria Presence of ≥5 RBC phpf 94%Hypercalciuria Urinary Ca excretion >4mg/kg/24h or >age-matched N 89%Nephrocalcinosis Renal US 76%Aminoaciduria urinary levels of amino acids 44%Nephrolithiasis Renal US 42%Chronic renal failure ESRD by age 30-50 y.o. 42%Hypophosphatemia Serum P <N level and tubular reapbsorption <85% 32%Rickets Rachitic changes in bone X-ray 32%Glycosuria ≥2 episodes of ≥(+) glycosuria without
hyperglycemia19%
Cho HY. Pediatr Nephrol 2008; 23:243-249;Claverie-Martin F. Pediatr Nephrol 2011; 26:693-704
Dent’s disease 1: renal biopsy findings
Hodgin JB. Kidney Int 2008; 73:1320-1323
a. Two glomeruli are globally sclerotic.
b. Normocellular glomeruli without segmental sclerosis or podocyte hypertrophy.
c. Many collecting ducts are distended by casts composed of Tamm-Horsfall protein admixed with calcifications.
d. Von Kossa stain is positive in the distribution of the calcifications, composed of calcium phosphate.
No indications for kidney biopsy in pts with phenotype of Dent’s disease!
Dent’s disease 1: characteristics in females
Females - obligate carriers with milder phenotype:
• Low-molecular-weight proteinuria: 60-90%
• Hypercalciuria: 30%
• Nephrocalcinosis - rare
• ESRD - rare
Sсheinman SJ. Kiney Int 1998; 53:3-17Ludwig M. et al. Pediatr Nephrol 2006; 21:1241-1250Copelovitch L. et al. Clin J Am Soc Nephrol 2007; 2:914-918
Dent’s disease 2 vs 1: characteristics in males
Major features
Dent 2 (OCRL1)
Dent 1 (CLCN5)
LMW proteinuria 100% 100%
Hypercalciuria 86% 90%
Nephrocalcinosis 39% 75%
Aminoaciduria 52% 41%
Chronic renal failure 32% 30%
Phosphate wasting 24% 22%
Glycosuria 11% 17%
Elevated serum levels of muscle enzymes (LDH, CPK)
frequently rare
Bokenkamp A. J Pediatr 2009; 155:94-99; Bokenhauer D. Pediatr Genetics 2011;
• SLC9A6, located on Xq26.3, encoding Na+/H+ exchanger
• TMEM27, located on Xp22.2, encoding collectrin
A further candidate gene awaits identification...
Ludwig M. Am J Med Genet 2004; 128:434-435;Hoopes R.R. Am J Hum Genet 2005; 76: 260-267;Tosseto E. Pediatr Nephrol 2009; 24:1967-1973;Wu F. Nephron Physiol 2009; 112:53-62.
No defects observed
Dent’s disease 1: pathophysiology
Devust O., Pirson Y. Kidney Int 2007; 72;1065-1072
Dent’s disease 1: pathophysiology
A. Small vesicles in the secondary foot processes of podocytes.B-C. Particles in podocytes
40000x40000x9000x
Dent’s disease 2: pathophysiology
Claverie-Martin F. Pediatr Nephrol 2011; 26:693-704
Edvardsson VO. et al. Pediatr Nephrol 2013; 10: 1923-1942
(> 100 mg per day)
Dent’s disease: diagnostic algorithm
Edvardsson VO. et al. Pediatr Nephrol 2013; 10: 1923-1942
(> 100 mg per day)
Dent’s disease: supportive treatment
Prevention of renal stone formation:
• No special dietary interventions
• High fluid intake
• Oral citrate
• Thiazides: risk of hypovolemia &
hypokalemia
Cebotary V. Am J Kidney 2005; 68:642-652
Dent’s disease: supportive treatment
Treatment of rickets:
• Vitamin D: doses -?
• Phosphate supplementation: doses -?
Slowing down the deterioration of renal function:
• High citrate diet delayed loss of kidney function in a mouse model,
no data in patients
• ACE inhibitors might be potential benefit by reducing proteinuria,
unknown effect on disease progression
Blanchard A. et al. Am J Kidney Dis 2008; 52:1084-1095
Risk of enhance hypercalciuria & nephrocalcinosis
Dent’s disease: prognosis
Kidney function:
• Normal during childhood
• ESRD in affected males : 30-80% in the 3rd to 5th decade
• ESRD in carrier females: 1 of 10
Renal transplantation:
• Most of patients with ESRD have kidney Tx with good success.
Wrong O.M. et al. Q.J.Med. 87:473-493, 1994;Bokenkamp A. J Pediatr 2009; 155:94-99.
Dent’s disease: conclusion
Open questions:
• How the mutations in Dent 1 (CLCN5) and Dent 2 (OCRL) produce a similar renal phenotype?
• Gene (s): Dent disease neither 1 nor 2?• Genotype-phenotype correlations?• Mechanism of hypercalciuria?• What percentage of FSGS pts might have unrecognized Dent disease?• What role of glomerular disfunction might play in the loss of renal
function?
Evidence-based statements: no
Dent’s disease: conclusion
• Keeping balance between potential benefit and harm to avoid withheld effective treatments or administering unnecessary treatments.
• Using of ‘expert groups’ with methodologists to balance personal experience and available evidence.
Further joint long-term clinical and genetic studies are needed.