Nephronophthisis and medullary cystic kidney disease

The inherited cystic kidney conditions nephronophthisis (NPHP) and medullary cystic kidney disease (MCKD) have previously been referred to as a NPHP–MCKD complex. This descriptive term was based on histological studies where the renal pathological features were common to both disorders. Both conditions may also present with insidious renal impairment and a urine concentrating defect, but they are genetically distinct. NPHP is an autosomal recessive disorder leading to established renal failure usually within the first three decades of life, and it is a ciliopathy. In contrast, MCKD is an autosomal dominantly inherited disorder leading to renal failure in later life, typically between 30 and 60 years of age. A molecular genetic diagnosis is helpful for both disorders, allowing a more precise diagnosis, screening of at risk relatives and avoiding the need for renal biopsy. Treatment of both conditions remains supportive.