Scientific Background
Nephronophthisis (NPHP) is an autosomal recessive inherited tubulointerstitial kidney disease, which belongs to the so-called ciliopathies. It is caused by a dysfunction of primary cilia. The incidence in Europe is estimated at approximately 1:50,000. The kidneys may be affected in isolation, but extrarenal manifestations such as retinitis pigmentosa (Senior-Løken syndrome), oculomotor apraxia (Cogan syndrome) as well as optic nerve coloboma and cerebellar vermis aplasia (Joubert syndrome) are also observed in 10‑40% of patients. The disease is phenotypically and genetically heterogeneous. So far, pathogenic variants in over 25 genes have been identified in association with NPHP. NPHP is divided into infantile (<4 years), juvenile (about 13 years) and adolescent/adult (about 19 years) forms depending on the average age at which terminal renal failure occurs. The most frequent form is juvenile NPHP, in which a homozygous deletion of the NPHP1 gene can be found in about 30-60% of patients. No genetic cause can be found in about 40-60% of NPHP patients.
References
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