Nephronophthisis Panel

Nephronophthisis (NPHP) is an autosomal recessive cystic kidney disease characterized by renal tubular atrophy and progressive interstitial fibrosis with the development of corticomedullary cysts. It is considered the most the most frequent genetic cause of renal failure in childhood or adolescence. Onset is typically marked by polydipsia and polyuria as a result of a defect in urine concentration. NPHP eventually progresses to end stage renal disease (ESRD), though the age of onset of ESRD varies. NPHP is generally classified based on the age of onset of ESRD: infantile (around age 1), juvenile (around age 13), or adolescent (around age 19). Additional findings include small-to-normal-sized hyperechogenic kidneys with reduced corticomedullary differentiation on abdominal ultrasonography and histopathological alterations characterized by thickened or disrupted tubular basement membranes, tubular atrophy and dilation, interstitial fibrosis and occasional renal cysts. The vast majority of cases of NPHP are isolated, however, about 10–15% of NPHP patients have additional extrarenal symptoms. These are often referred to as nephronophthisis-associated ciliopathies and symptoms may include retinitis pigmentosa (Senior-Loken syndrome, Bardet-Biedl syndrome, Alstrom syndrome), liver fibrosis, cerebellar vermis hypoplasia (Joubert syndrome), and multiple developmental and neurologic abnormalities (Meckel Gruber syndrome). The panel includes sequence and deletion/duplication analysis of all the listed genes.