The nephronophthisis complex: clinical and genetic aspects

Area of Science:

• Nephrology
• Genetics
• Pediatric Nephrology

Background:

• Familial juvenile nephronophthisis (NPH) and medullary cystic disease (MCD) are hereditary conditions leading to early-onset chronic renal failure.
• These diseases are characterized by bilateral kidney cyst formation at the corticomedullary junction, often presenting with polyuria, polydipsia, anemia, and growth retardation.

Purpose of the Study:

• To summarize the clinical and pathological characteristics of NPH and MCD.
• To highlight the diagnostic challenges and the need for improved detection methods.

Main Methods:

• Review of existing literature on NPH and MCD.
• Analysis of clinical presentations, inheritance patterns, and pathological findings.

Main Results:

• NPH and MCD are clinically and pathologically similar, differentiated by age of onset and inheritance (autosomal recessive for NPH, autosomal dominant for MCD).
• The absence of edema and hypertension can delay diagnosis, making it a significant cause of end-stage renal disease in children (10-25%).
• Associated conditions include Senior-Løken syndrome (NPH with retinitis pigmentosa), hepatic fibrosis, skeletal defects, and CNS abnormalities in NPH.

Conclusions:

• The term "nephronophthisis complex" encompasses these related kidney diseases due to shared pathology.
• Current diagnostic capabilities lack methods for heterozygote identification, prenatal diagnosis, or screening within affected families.
• Histological findings show characteristic, though not specific, chronic sclerosing tubulo-interstitial nephropathy with corticomedullary cysts.